Autonomous Switch Research Articles

Rigid Polymer Network-Based Autonomous Photoswitches Working in the Solid State Encoded by Room-Temperature Phosphorescence

Autonomous molecular switches with self-recoverability are of great theoretical and experimental interest since they can avoid additional chemical or energy imposition during the working process. Due to the high energy barrier, however, the solid state is generally unfavorable for materials to exhibit the autonomous switch behavior. To promote the practical usage of the autonomous molecular switch, herein, we propose a prototype of an autonomous photoswitch that can work in the solid state based on a rigid polymer network. A hexacarboxylic sodium-modified hexathiobenzene compound was employed as a photoexcitation-driven unit, which can undergo molecular aggregation upon irradiation because of the distinct conformational difference between the ground state and the photoexcited state. Then, we selected a relatively rigid polymer named poly(dimethyldiallylammonium)chloride (PDDA) to complex with the hexacarboxylic sodium-modified hexathiobenzene through electrostatic coupling. Through optimization, the photoexcitation-controlled molecular aggregation and its self-recovery can work well in the solid matrix of PDDA under rhythmical photoirradiation. This process can be easily encoded by a self-recoverable room-temperature phosphorescence, featuring an excellent performance of the autonomous switch.

An autonomous switch based on a rotating magnet driven by magnetic launchers

This paper reports on an innovative electromagnetic energy harvester for autonomous switches relying on a rotating magnet driven by magnetic launchers, and combined with a ferromagnetic circuit and a coil to turn the variation of magnetic flux induced by the rotating magnet into electricity. The device is able to operate on forward and backward translation movements. The energy harvester has been modeled, optimized, manufactured, characterized and integrated into a mechanical actuation system to form a complete autonomous switch that will be commercially available. The experimental output energy reaches 1.235 mJ (350 µJ cm−3) which is among the highest output energies and energy densities reached on autonomous switches in the state of the art. The electromechanical conversion efficiency is 56%, which is excellent for an energy harvester, and obtained thanks to the topology chosen for the electromagnetic converter. The energy harvester is finally connected to a diode-bridge-capacitor circuit to supply the RF emission of the commands with a Zigbee Green Power® transmitter.

Unstructured kinetic models to simulate an arabinose switch that decouples cell growth from metabolite production

Modeling synthetic gene circuits to implement dynamic flux balancing is crucial in teaching and exploring metabolic engineering strategies to repartition metabolic precursors and construct efficient microbial cell factories. Microbial fitness and production rates are often complex phenotypes that are governed by highly non-linear, multivariable functions which are intrinsically linked through carbon metabolism. The solution of such dynamic system can be difficult for synthetic biologists to visualize or conceptualize. Recently, researchers (Santala et al., Metab. Eng. Comm., 2018) have implemented an arabinose based genetic switch to dynamically partition the central carbon flux between cell growth and product formation. The autonomous switch allowed dynamic shift from arabinose-associated cell growth to acetate-associated product (wax ester) formation. This system clearly demonstrates the effectiveness of using a genetic switch to decouple cell growth from product formation in a one-pot bioreactor to minimize operational cost. Coupled with Michaelis-Menten kinetics, and Luedeking-Piret equations, we were able to reconstruct and analyze this metabolic switch in silica and achieved graphical solutions that qualitatively match with the experimental data. By assessing physiologically-accessible parameter space, we observed a wide range of dynamic behavior and examined the different limiting cases. Graphical solutions for this dynamic system can be viewed simultaneously and resolved in real time via buttons on the graphical user interface (GUI). Metabolic bottlenecks in the system can be accurately predicted by varying the respective rate constants. The GUI serves as a diagnosis toolkit to troubleshoot genetic circuits design constraints and as an interactive workflow of using this arabinose based genetic switch to dynamically control carbon flux, which may provide a valuable computational toolbox for metabolic engineers and synthetic biologists to simulate and understand complex genetic-metabolic system.

Improving adoption of liquefied petroleum gas (LPG) for better health and conservation outcomes

ABSTRACT Poverty, energy inequality and poor human health are interrelated issues. In India, around 625 million people do not have access to modern cooking fuels, and traditional fuels still provide 80–90% of the country’s rural energy needs. For villages in and around forest areas that are dependent on fuelwood, this dramatically increases anthropogenic pressure on the forests. Such dependency adversely affects the health of the individuals using these traditional fuels, due to indoor air pollution, as well as the health of the surrounding environment, via forest degradation; it also increases incidences of human–animal conflict. Subsidies for liquefied petroleum gas (LPG) have been pivotal in shifting household preferences towards cleaner sources of energy. An analysis of 3124 households conducted for this study in the Chandrapur district, Maharashtra, India, in February 2018 revealed that apart from the income level of a household, other factors such as improving the education of women and reducing their distance traveled to obtain LPG refills should be looked at to improve LPG adoption rates. Key policy insights Building an efficient distribution network for LPG that reduces the distance traveled for refills is a key requirement for enhancing adoption of LPG The health benefits and environmental benefits emphasize that LPG is a public good, justifying its targeted subsidization for the marginalized population Affordability is a necessary, but not sufficient, condition for LPG adoption. Thus, increasing incomes does not lead to an autonomous switch to cleaner fuels. This underscores the need for promotion and awareness of using LPG Better education of women leads to higher adoption of LPG by the household

Synthetic Gene Circuits Enable Escherichia coli To Use Endogenous H2S as a Signaling Molecule for Quorum Sensing.

Microorganisms often use specific autoinducers other than common metabolites for quorum sensing (QS). Herein, we demonstrated that Escherichia coli produced sulfide (H2S, HS-, and S2-) with the concentrations proportionally correlated to its cell density. We then designed synthetic gene circuits that used H2S as an autoinducer for quorum sensing. A sulfide/quinone oxidoreductase converted diffusible H2S to indiffusible hydrogen polysulfide (HSnH, n ≥ 2), and a gene regulator CstR sensed the latter to turn on the gene expression. We constructed three element libraries, with which 24 different circuits could be assembled for adjustable sensitivity to cell density. The H2S-mediated gene circuits endowed E. coli cells within the same batch or microcolony with highly synchronous behaviors. Using them we successfully constructed cell factories capable of an autonomous switch from growth phase to production phase. Thus, these circuits provide a new tool-kit for metabolic engineering and synthetic biology.

Regulation of germ cell sex identity in medaka.

Germline stem cells are sexually indifferent or flexible even in the mature ovary and testis. Acquiring sex identity consistent with the sex of the body is a critical issue in germline stem cells for producing eggs or sperm. However, the molecular mechanism of the sexual fate decision in germ cells is unclear. Medaka is the first vertebrate in which germline stem cells were found in the mature ovary (Nakamura, Kobayashi, Nishimura, Higashijima, & Tanaka, 2010), and a germ cell autonomous switch gene involved in the sexual fate decision, foxl3, was identified (Nishimura et al., 2015) in vertebrates. Here, the mechanism underlying the sex identity of germ cells is described based on the current understanding of germ cell behavior during the sexual fate decision. The control of foxl3 expression in germ cells and components acting downstream of foxl3 are also described.

TrustZone의 시큐어 타이머를 이용한 효율적인 커널 검사 시스템

Kernel rootkit is recognized as one of the most severe and widespread threats to corrupt the integrity of an operating system. Without an external monitor as a root of trust, it is not easy to detect kernel rootkits which can intercept and modify communications at the interfaces between operating system components. To provide such a monitor isolated from an operating system that can be compromised, most existing solutions are based on external hardware. Unlike those solutions, we develop a kernel introspection system based on the ARM TrustZone technology without incurring extra hardware cost, which can provide a secure memory space in isolation from the rest of the system. We particularly use a secure timer to implement an autonomous switch between secure and non-secure modes. To ensure integrity of reference, this system measured reference from vmlinux which is a kernel original image. In addition, the flexibility of monitoring block size can be configured for efficient kernel introspection system. The experimental results show that a secure kernel introspection system is provided without incurring any significant performance penalty (maximum 6% decrease in execution time compared with the normal operating system).

Time-slot based event-driven network switch control for information sharing in multiple WLANs

Recent wireless LAN technologies and service management technologies have produced widely diverse network services with no configuration task or effort for end-users' consumer electronics (CE) devices. This environment needs a mechanism that enables end-users to access services seamlessly across separated networks. To provide such accessibility, information for services in multiple networks should be available in each terminal that is currently connected to a wireless LAN. This paper presents a proposal of a new mechanism to collect and manage service information belonging to different WLANs autonomously for end-users. Specifically, an autonomous network switch and event-driven service information sharing scheme are proposed. The functionalities which are embedded on end-user CE devices require no central control device on a WLAN or the internet and require no modification of WLAN access points. The effectiveness of the proposal is demonstrated using simulation experiments. Future work is described.

Représentations continues de systèmes hybrides

This article introduces continuous representations for two classes of hybrid systems with either controlled jumps and switches or autonomous switch. These representations enable to avoid difficulties associated with discontinuities. The studied hybrid systems and their associated continuous systems are first introduced, and some convergences between the states of continuous systems and those of hybrid systems are formulated. Then, optimal control and identification problems are introduced, and convergence results that justify the use of continuous representations for their resolution, are written. Finally, the advantages and technical simplifications brought by the representations throughout the resolution of these problems are highlighted.

Lessons for Other Industries from Australia's Booming Wine Industry

Opportunities for export-led growth by Australia's rural industries are improving as East Asia returns to growth, agricultural protectionist barriers start to be lowered abroad, deregulation of domestic markets continue, and the costs of international transportation and communications drop. Taking advantage of those opportunities requires a concerted effort, however. It therefore makes sense for rural industries seeking to export their way to greater prosperity to look to lessons that can be drawn from other successful industries. There is no more spectacular success story in Australia than the wine industry during the past decade. The industry's dramatic growth over the past dozen years was initially stimulated by a 30 per cent decline in the Australian dollar's real exchange rate in the first half of the 1980s. In the mid-1980s virtually all segments of the industry were domestically focussed, whereas exports now account for 30 per cent of all wine production. Increased export demand explains much of the industry's growth over the 1990s. This has come about through an increasing emphasis on quality in the industry, sustained generic and brand marketing efforts that have greatly boosted Australia's image as a producer of good value-for-money wines overseas, the development of more-effective distribution systems in key markets abroad, and an autonomous switch by consumers both in Australia and elsewhere towards premium wine (driven in part by health considerations, especially for reds). That success has been achieved despite export growth by other New World wine producers and an environment where global wine consumption is declining. That has been possible because the demand for premium wine has been growing rapidly, at the expense of non-premium wine, and Australia's production is being increasingly oriented towards higher-quality products. The clearest implication for other industries is that dramatic export-led expansion is possible but not without substantial hard work and large synergistic investments of time, effort and money in all three stages of the production process (primary production, processing, and marketing/ distribution). More specifically, as the illustrations discussed in the paper for the olive and dairy industries show: market niches have to be precisely identified at home and abroad; a long-term vision for sustainable growth, based on sound and detailed statistics, is needed to help attract/retain investment funds; training courses and research need to accompany or preferably precede investments in primary production, processing plants and promotion; and where vertical integration is not complete, good relations between primary producers and processors/marketers need to be developed.

A 16×622 Mb/s ATM switch: PRELUDE switch architecture integrated into a 6-million transistor monochip

This paper presents the integration of the Prelude switch architecture into a monochip ATM switch, COM16M, capable of handling 16 multiplexes carrying ATM cells at 622 Mb/s. It is a fully autonomous switch, i.e., the chip includes clock adaptation, routing, and cell buffering as well as header translation and control capabilities. The switch is integrated into one single chip containing 6000000 transistors implemented in a 0.5-/spl mu/m CMOS process.