Boosting the electron beam transmittance of field emission cathode using a self-charging gate.

The gate-type carbon nanotubes cathodes exhibit advantages in long-term stable emission owing to the uniformity of electrical field on the carbon nanotubes, but the gate inevitably reduces the transmittance of electron beam, posing challenges for system stabilities. In this work, we introduce electron beam focusing technique using the self-charging SiNx/Au/Si gate. The potential of SiNx is measured to be approximately -60 V quickly after the cathode turning on, the negative potential can be maintained as the emission goes on. The charged surface generates rebounding electrostatic forces on the following electrons, significantly focusing the electron beam on the center of gate hole and allowing them to pass through gate with minimal interceptions. An average transmittance of 96.17% is observed during 550 hours prototype test, the transmittance above 95% is recorded for the cathode current from 2.14 µA to 3.25 mA with the current density up to 17.54 mA cm-2.

Cooperative microbial interactions drive spatial segregation in porous environments.

The role of microbial interactions and the underlying mechanisms that shape complex biofilm communities are poorly understood. Here we employ a microfluidic chip to represent porous subsurface environments and show that cooperative microbial interactions between free-living and biofilm-forming bacteria trigger active spatial segregation to promote their respective dominance in segregated microhabitats. During initial colonization, free-living and biofilm-forming microbes are segregated from the mixed planktonic inoculum to occupy the ambient fluid and grain surface. Contrary to spatial exclusion through competition, the active spatial segregation is induced by cooperative interactions which improves the fitness of both biofilm and planktonic populations. We further show that free-living Arthrobacter induces the surface colonization by scavenging the biofilm inhibitor, D-amino acids and receives benefits from the public goods secreted by the biofilm-forming strains. Collectively, our results reveal how cooperative microbial interactions may contribute to microbial coexistence in segregated microhabitats and drive subsurface biofilm community succession.

A newly designed decoupling method for micro-Newton thrust measurement.

A decoupling method is proposed for micro-Newton thrust measurement with a torsion pendulum. The basic approach is to reduce the influences introduced by the propellant tube and wires of the thruster. A hollow aluminum tube is used to hang the torsion pendulum and is also chosen as the transport pipe for the propellant of the thruster. The electric control box of the thruster is mounted on the pendulum body, which is powered by an externally installed power supply through a liquid metal conductive unit. The control of the electric control box is performed through wireless transmission. With this design, the influences of the propellant tube and connection wires between the torsion pendulum and the outside device are reduced and the stability of the torsion spring constant of the system can be improved. The use of the liquid metal conductive unit reduces the coupling between the wires and the measurement system. The feasibility of the wireless transmission is analyzed. The error sources during the thrust measurement are analyzed, and the expected three σ uncertainty of the thrust is 0.032+(0.10%*F)2µN for the measurement of the cold gas thruster. The scheme provides a thrust measurement with higher precision and stability.

Research on Competition and Cooperation Relationship of TV-Drama Production Company Based on Social Network.

The social network is affecting the connection of TV-drama production companies, and traditional partnerships are changing. Many companies are moving from traditional connections to gridded social networks. The changing relational network makes the relationship between TV-drama production companies change from linear and static to network and dynamic, and from the original cooperation based on "Contract" to the node-type cooperation of "Switch." Through empirical study, the paper found that the social network relationship in the TV series production industry has become an essential social capital because the construction of social networks will effectively promote the development of the industry under the new competition and make TV-drama industry production chain, creative resources, and value derived channel, resource boundary and cooperation mechanism, and market competition pattern change. Ultimately, it will reshape the subject cognition, path cognition, and power cognition in the relationship network.

Creating Sustainable Cultural Industries: The Perspective of Artificial Intelligence and Global Value Chain.

In the era of artificial intelligence (AI), cultural industries have introduced new development opportunities, and their global value chain (GVC) position is receiving more attention. This study uses panel data from global cross-borders from 56 countries (regions) as the research sample to empirically analyze the impact of AI on improving the GVC position of cultural industries using the double fixed effects regression model and examines the heterogeneity effect. The results confirm that there is a significant positive correlation between AI and the GVC position of cultural industries. The mechanism test shows that AI impacts the division of labor position in the GVC of cultural industries mainly through technological innovation and the industrial structure. Heterogeneity analysis shows that AI has a significant effect on promoting the cultural industry's GVC position in high-income countries (regions) but it has no significant effect on low- and middle-income countries (regions). The results of this study can provide a useful reference for improving the division of labor positions in the GVC and better promoting the development of cultural industries.

A compound pendulum for thrust measurement of micro-Newton thruster.

A thrust stand is developed for testing micro-Newton level thrusters on the ground. The stand is composed of a compound pendulum that is symmetrically suspended by two thin beryllium copper strips, and it is precisely calibrated by gravity. The stiffness of the stand can be adjusted in 3 orders of magnitude by a counterweight. When the stiffness is larger than 1 Nm/rad, the stand demonstrates a fast response to thrust. The measured range of the stand reaches 1000 µN, and the noise is less than 0.1 µN/Hz within 1 mHz-1 Hz. To calibrate the resolution of the stand, an electrostatic force is applied to the stand with an actuator. The equivalent thrust is determined to be 0.09 µN with a standard uncertainty of 0.02 µN. Using the stand, a micro-Newton colloid thruster is tested. The output of the colloid thruster changes with the applied voltage as 0.015(1) µN/V. When changing the voltage by 50 V, the change in thrust is measured to be 0.7 µN with a standard uncertainty of 0.1 µN.

An Intelligent Digital Media Asset Management Model Based on Business Ecosystem.

In the context of media convergence, it is of great significance to study and discuss the intelligent digital media asset management model and build a digital media asset management ecosystem model to carry out effective digital media asset management for media organizations and promote the value creation of digital media content assets. Based on the business ecosystem, this study adopts a system dynamics approach to construct a system dynamics model through theoretical research and simulation analysis. By studying the positioning of intelligent digital media asset management and service patterns, the basic framework of digital media asset management ecosystems is proposed. To explore the interaction between different factors, the system dynamics model of value creation in digital media asset management ecosystems is built in this paper. This study provides new insights for media organizations on building an intelligent digital media asset management model and promoting the development and utilization of media content resources.

Role of microfluidics in accelerating new space missions.

Numerous revolutionary space missions have been initiated and planned for the following decades, including plans for novel spacecraft, exploration of the deep universe, and long duration manned space trips. Compared with space missions conducted over the past 50 years, current missions have features of spacecraft miniaturization, a faster task cycle, farther destinations, braver goals, and higher levels of precision. Tasks are becoming technically more complex and challenging, but also more accessible via commercial space activities. Remarkably, microfluidics has proven impactful in newly conceived space missions. In this review, we focus on recent advances in space microfluidic technologies and their impact on the state-of-the-art space missions. We discuss how micro-sized fluid and microfluidic instruments behave in space conditions, based on hydrodynamic theories. We draw on analyses outlining the reasons why microfluidic components and operations have become crucial in recent missions by categorically investigating a series of successful space missions integrated with microfluidic technologies. We present a comprehensive technical analysis on the recently developed in-space microfluidic applications such as the lab-on-a-CubeSat, healthcare for manned space missions, evaluation and reconstruction of the environment on celestial bodies, in-space manufacturing of microfluidic devices, and development of fluid-based micro-thrusters. The discussions in this review provide insights on microfluidic technologies that hold considerable promise for the upcoming space missions, and also outline how in-space conditions present a new perspective to the microfluidics field.

Instantaneous Self-Powered Sensing System Based on Planar-Structured Rotary Triboelectric Nanogenerator.

Self-powering electronics by harvesting mechanical energy has been widely studied, but most self-powering processes require a long time in the energy harvesting procedure, resulting in low efficiency or even system failure in some specific applications such as instantaneous sensor signal acquisition and transmission. In order to achieve efficient self-powered sensing, we design and construct an instantaneous self-powered sensing system, which puts heavy requirements on generator's power and power management circuit. Theoretical analysis and experimental results over two types of generators prove that the planar-structured rotary triboelectric nanogenerator possesses many advantages over electromagnetic generator for the circumstances of instantaneous self-powering. In addition, an instantaneous driving mode power management circuit is also introduced showing advanced performance for the instantaneous self-powering sensing system. As a proof-of-concept, an integrated instantaneous self-powered sensing system is demonstrated based on Radio-Frequency transmission. This work demonstrates the potential of instantaneous self-powered sensing systems to be used in a wide range of applications such as smart home, environment monitoring, and security surveillance.

Self-adaptive Bioinspired Hummingbird-wing Stimulated Triboelectric Nanogenerators.

Bio-inspired technologies have remarkable potential for energy harvesting from clean and sustainable energy sources. Inspired by the hummingbird-wing structure, we propose a shape-adaptive, lightweight triboelectric nanogenerator (TENG) designed to exploit the unique flutter mechanics of the hummingbird for small-scale wind energy harvesting. The flutter is confined between two surfaces for contact electrification upon oscillation. We investigate the flutter mechanics on multiple contact surfaces with several free-standing and lightweight electrification designs. The flutter driven-TENGs are deposited on simplified wing designs to match the electrical performance with variations in wind speed. The hummingbird TENG (H-TENG) device weighed 10 g, making it one of the lightest TENG harvesters in the literature. With a six TENG network, the hybrid design attained a 1.5 W m-2 peak electrical output at 7.5 m/s wind speed with an approximately linear increase in charge rate with the increased number of TENG harvesters. We demonstrate the ability of the H-TENG networks to operate Internet of Things (IoT) devices from sustainable and renewable energy sources.

A Self-Powered Implantable Drug-Delivery System Using Biokinetic Energy.

The first triboelectric-nanogenerator (TENG)-based self-powered implantable drug-delivery system is presented. Pumping flow rates from 5.3 to 40 µL min-1 under different rotating speeds of the TENG are realized. The implantable drug-delivery system can be powered with a TENG device rotated by human hand motion. Ex vivo trans-sclera drug delivery in porcine eyes is demonstrated by utilizing the biokinetic energies of human hands.

Synthesis and characterization of multifunctional hybrid-polymeric nanoparticles for drug delivery and multimodal imaging of cancer.

In this study, multifunctional hybrid-polymeric nanoparticles were prepared for the treatment of cultured multicellular tumor spheroids (MCTS) of the PANC-1 and MIA PaCa-2 pancreatic carcinoma cell lines. To synthesize the hybrid-polymeric nanoparticles, the poly lactic-co-glycolic acid core of the particles was loaded with Rhodamine 6G dye and the chemotherapeutic agent, Paclitaxel, was incorporated into the outer phospholipid layer. The surface of the nanoparticles was coated with gadolinium chelates for magnetic resonance imaging applications. This engineered nanoparticle formulation was found to be suitable for use in guided imaging therapy. Specifically, we investigated the size-dependent therapeutic response and the uptake of nanoparticles that were 65 nm, 85 nm, and 110 nm in size in the MCTS of the two pancreatic cancer cell lines used. After 24 hours of treatment, the MCTS of both PANC-1 and MIA PaCa-2 cell lines showed an average increase in the uptake of 18.4% for both 65 nm and 85 nm nanoparticles and 24.8% for 110 nm nanoparticles. Furthermore, the studies on therapeutic effects showed that particle size had a slight influence on the overall effectiveness of the formulation. In the MCTS of the MIA PaCa-2 cell line, 65 nm nanoparticles were found to produce the greatest therapeutic effect, whereas 12.8% of cells were apoptotic of which 11.4% of cells were apoptotic for 85 nm nanoparticles and 9.79% for 110 nm nanoparticles. Finally, the study conducted in vivo revealed the importance of nanoparticle size selection for the effective delivery of drug formulations to the tumors. In agreement with our in vitro results, excellent uptake and retention were found in the tumors of MIA PaCa-2 tumor-bearing mice treated with 110 nm nanoparticles.

An in-vivo evaluation of a MEMS drug delivery device using Kunming mice model.

The use of MEMS implantable drug delivery pump device enables one to program the desired drug delivery profile in the device for individualized medicine treatment to patients. In this study, a MEMS drug delivery device is prepared and employed for in vivo applications. 12 devices are implanted subcutaneously into Kunming mice for evaluating their long term biocompatibility and drug-delivery efficiency in vivo. All the mice survived after device implantation surgery procedures. Histological analysis result reveals a normal wound healing progression within the tissues-to-device contact areas. Serum analysis shows that all measured factors are within normal ranges and do not indicate any adverse responses associated with the implanted device. Phenylephrine formulation is chosen and delivered to the abdominal cavity of the mice by using either the implanted MEMS device (experimental group) or the syringe injection method (control group). Both groups show that they are able to precisely control and manipulate the increment rate of blood pressure in the small animals. Our result strongly suggests that the developed refillable implantable MEMS devices will serve as a viable option for future individualized medicine applications such as glaucoma, HIV-dementia and diabetes therapy.

Standalone Lab-on-a-Chip Systems toward the Evaluation of Therapeutic Biomaterials in Individualized Disease Treatment.

As each tumor is unique, treatments should be individualized in terms of their drug formulation and time dependent dosing. In vitro lab-on-a-chip (LOC) drug testing is a viable avenue to individualize treatments. A drug testing platform in the form of a customizable standalone LOC system is proposed for treatment individualization in vitro. The platform was used to individualize the treatment of pancreatic cancer by using PANC-1 and MIA PaCa-2 cell lines cultured on-chip. Using on-chip drug uptake, growth, and migration inhibition assays, the therapeutic effect of various treatment combinations was analyzed. Thereafter, optimized treatments were devised for each cell line. The individualized dosage for MIA PaCa-2 cell line was found to be between 0.05-0.1 µg/µL of doxorubicin (DOX), where the greatest growth and migration inhibition effects were observed. As the PANC-1 cell line showed resistance to DOX only formulations, a multidrug approach was used for individualized treatment. Compared to the DOX only formulations, the individualized treatment produced the same degree of migration inhibition but with 5-10 times lower concentration of DOX, potentially minimizing the side-effects of the treatment. Furthermore, the individualized treatment had an average of 672.4% higher rate of growth inhibition. Finally, a preliminary study showed how a tested formulation from the LOC system can be translated for use by employing a nanoparticle system for controlled delivery, producing similar therapeutic effects. The use of such systems in clinical practice could potentially revolutionize treatment formulation by maximizing the therapeutic effects of existing treatments while minimizing their potential side effects through individualization of treatment.

Preparation of biofunctionalized quantum dots using microfluidic chips for bioimaging.

Biofunctionalized quantum dots (QDs), especially protein-coated QDs, are known to be useful targeted fluorescent labels for cellular and deep-tissue imaging. These nanoparticles can also serve as efficient energy donors in fluorescence resonance energy transfer (FRET) binding assays for the multiplexed sensing of tumor markers. However, current preparation processes for protein-functionalized QDs are laborious and require multiple synthesis steps (e.g. preparing them in high temperature, making them dispersible in water, and functionalizing them with surface ligands) to obtain a high quality and quantity of QD formulations, significantly impeding the progress of employing QDs for clinical diagnostics use such as a QD-based immunohistofluorescence assay. Herein, we demonstrate a one-step synthesis approach for preparing protein-functionalized QDs using a microfluidic (MF) chip setup. Using bovine serum albumin (BSA) molecules as the surface ligand model, we first studied and optimized the MF reaction synthesis parameters (e.g. reaction temperature, and channel width and length) for making protein-functionalized QDs using COMSOL simulation modeling, followed by experimental verification. Moreover, in comparison with the BSA-functionalized QDs synthesized using the conventional bench-top method, BSA-QDs prepared using the MF approach exhibit a significantly higher protein-functionalization efficiency, photostability and colloidal stability. The proposed one-step MF synthesis approach provides a rapid, cost effective, and a small-scale production of nanocrystals platform for developing new QD formulations in applications ranging from cell labeling to biomolecular sensing. Most importantly, this approach will considerably reduce the amount of chemical waste generated during the trial-and-error stage of developing and perfecting the desired physical and optical properties of new QD materials.

High reliability nanosandwiched Pt/Ti multilayer electrode actuators for on-chip biomedical applications.

Microactuators provide the main driving force for fluid pumping in microfluidic devices and thus play an important role in on-chip biomedical applications. Interdigitated electrode based electrochemical actuators have provided a viable choice for effective actuation with advantages of flexible controllability, biocompatibility and ease of fabrication. However, the current feature size of a typical electrode structure is around 100 µm, which is relatively large for device miniaturization and integration. Further decrease in the feature size will lead to dramatic decrease in the reliability and lifetime of the actuators, caused by metal delamination. In this work, we propose a novel design of electrodes to fabricate a new type of microactuator with high reliability. To prevent the occurrence of delamination, a nanosandwiched multilayer structure of titanium/platinum is used to construct the conductive metal layer for the interdigitated electrodes. The feature size of the electrodes is greatly reduced to 20 µm where we have reduced the size by 80% of the similar structures reported previously. At the same time, the lifetime of the new electrodes has been dramatically increased to over 400% as compared to the conventional design. With these remarkable improvements in the electrode design, we have fabricated a prototype microfluidic device integrating the new microactuator for drug tests in cancer therapy, demonstrating its usefulness for on-chip biomedical applications.

An electrochemically actuated MEMS device for individualized drug delivery: an in vitro study.

Individualized disease treatment is a promising branch for future medicine. In this work, we introduce an implantable microelectromechanical system (MEMS) based drug delivery device for programmable drug delivery. An in vitro study on cancer cell treatment has been conducted to demonstrate a proof-of-concept that the engineered device is suitable for individualized disease treatment. This is the first study to demonstrate that MEMS drug delivery devices can influence the outcome of cancer drug treatment through the use of individualized disease treatment regimes, where the strategy for drug dosages is tailored according to different individuals. The presented device is electrochemically actuated through a diaphragm membrane and made of polydimethylsiloxane (PDMS) for biocompatibility using simple and cost-effective microfabrication techniques. Individualized disease treatment was investigated using the in vitro programmed delivery of a chemotherapy drug, doxorubicin, to pancreatic cancer cell cultures. Cultured cell colonies of two pancreatic cancer cell lines (Panc-1 and MiaPaCa-2) were treated with three programmed schedules and monitored for 7 days. The result shows that the colony growth has been successfully inhibited for both cell lines among all the three treatment schedules. Also, the different observations between the two cell lines under different schedules reveal that MiaPaCa-2 cells are more sensitive to the drug applied. These results demonstrate that further development on the device will provide a promising novel platform for individualized disease treatment in future medicine as well as for automatic in vitro assays in drug development industry.