A novel method to monitoring changes in cognitive load in video‐based learning

One of the golden rules in instructional design methods is to optimize the use of working memory capacity and avoid cognitive overload. The study of cognitive load has historically relied on one's introspection. However, it is difficult to capture changes in cognitive load levels during learning sensitively. This paper suggests an approach to investigating dynamic changes in cognitive load by using a pupillometry. With the method, this study explores the effects of learners' prior knowledge and task complexity on cognitive load. An experiment was conducted on two groups of students (N = 19) with distinct levels of prior knowledge. In the experimental session, participants watched a video lecture on a mathematics proposition, while being eye‐tracked. The lecture consists of sections, which can be either a high task complexity or a low task complexity based on elements they have. Pupil dilations acquired in each section were used to explore the time course of cognitive load. To formulate cognitive load patterns, a time‐series clustering was used. The research conducted a chi‐square analysis to test differences in cognitive load patterns by prior knowledge and task complexity. Results show that pupil dilation patterns can be applied to monitor changes in cognitive load during learning.     

Room‐Temperature Metallic Fusion‐Induced Layer‐by‐Layer Assembly for Highly Flexible Electrode Applications

To fabricate flexible electrodes, conventional silver (Ag) nanomaterials have been deposited onto flexible substrates, but the formed electrodes display limited electrical conductivity due to residual bulky organic ligands, and thus postsintering processes are required to improve the electrical conductivity. Herein, an entirely different approach is introduced to produce highly flexible electrodes with bulk metal–like electrical conductivity: the room‐temperature metallic fusion of multilayered silver nanoparticles (NPs). Synthesized tetraoctylammonium thiosulfate (TOAS)‐stabilized Ag NPs are deposited onto flexible substrates by layer‐by‐layer assembly involving a perfect ligand‐exchange reaction between bulky TOAS ligands and small tris(2‐aminoethyl)amine linkers. The introduced small linkers substantially reduce the separation distance between neighboring Ag NPs. This shortened interparticle distance, combined with the low cohesive energy of Ag NPs, strongly induces metallic fusion between the close‐packed Ag NPs at room temperature without additional treatments, resulting in a high electrical conductivity of ≈1.60 × 10⁵ S cm^?1 (bulk Ag: ≈6.30 × 10⁵ S cm^?1). Furthermore, depositing the TOAS–Ag NPs onto cellulose papers through this approach can convert the insulating substrates into highly flexible and conductive papers that can be used as 3D current collectors for energy‐storage devices.     

Self‐Powered Chemical Sensing Driven by Graphene‐Based Photovoltaic Heterojunctions with Chemically Tunable Built‐In Potentials

Ultralow power chemical sensing is essential toward realizing the Internet of Things. However, electrically driven sensors must consume power to generate an electrical readout. Here, a different class of self‐powered chemical sensing platform based on unconventional photovoltaic heterojunctions consisting of a top graphene (Gr) layer in contact with underlying photoactive semiconductors including bulk silicon and layered transition metal dichalcogenides is proposed. Owing to the chemically tunable electrochemical potential of Gr, the built‐in potential at the junction is effectively modulated by absorbed gas molecules in a predictable manner depending on their redox characteristics. Such ability distinctive from bulk photovoltaic counterparts enables photovoltaic‐driven chemical sensing without electric power consumption. Furthermore, it is demonstrated that the hydrogen (H₂) sensing properties are independent of the light intensity, but sensitive to the gas concentration down to the 1 ppm level at room temperature. These results present an innovative strategy to realize extremely energy‐efficient sensors, providing an important advancement for future ubiquitous sensing.     

Exploiting Colloidal Metamaterials for Achieving Unnatural Optical Refractions

The scaling down of meta-atoms or metamolecules (collectively denoted as metaunits) is a long-lasting issue from the time when the concept of metamaterials was first suggested. According to the effective medium theory, which is the foundational concept of metamaterials, the structural sizes of meta-units should be much smaller than the working wavelengths (e.g., << 1/5 wavelength). At relatively low frequency regimes (e.g., microwave and terahertz), the conventional monolithic lithography can readily address the materialization of metamaterials. However, it is still challenging to fabricate optical metamaterials (metamaterials working at optical frequencies such as the visible and near-infrared regimes) through the lithographic approaches. This serves as the rationale for using colloidal self-assembly as a strategy for the realization of optical metamaterials. Colloidal self-assembly can address various critical issues associated with the materialization of optical metamaterials, such as achieving nanogaps over a large area, increasing true 3D structural complexities, and cost-effective processing, which all are difficult to attain through monolithic lithography. Nevertheless, colloidal self-assembly is still a toolset underutilized by optical engineers. Here, the design principle of the colloidally self-assembled optical metamaterials exhibiting unnatural refractions, the practical challenge of relevant experiments, and the future opportunities are critically reviewed.     

Cuproptosis-Inducible Chemotherapeutic/Cascade Catalytic Reactor System for Combating with Breast Cancer

Cascade hydroxyl radical generating hydrogel reactor structures including a chemotherapeutic agent are invented for multiple treatment of breast cancer. Glucose oxidase (GOx) and cupric sulfate (Cu) are introduced for transforming accumulated glucose (in cancer cells) to hydroxyl radicals for starvation/chemodynamic therapy. Cu may also suppress cancer cell growth via cuproptosis-mediated cell death. Berberine hydrochloride (BER) is engaged as a chemotherapeutic agent in the hydrogel reactor for combining with starvation/chemodynamic/cuproptosis therapeutic modalities. Moreover, Cu is participated as a gel crosslinker by coordinating with catechol groups in hyaluronic acid-dopamine (HD) polymer. Controlling viscoelasticity of hydrogel reactor can extend the retention time following local injection and provide sustained drug release patterns. Low biodegradation rate of designed HD/BER/GOx/Cu hydrogel can reduce dosing frequency in local cancer therapy and avoid invasiveness-related inconveniences. Especially, it is anticipated that HD/BER/GOx/Cu hydrogel system can be applied for reducing size of breast cancer prior to surgery as well as tumor growth suppression in clinical application.     

Towards Media Inter-cloud Standardization – Evaluating Impact of Cloud Storage Heterogeneity

Digital media has been increasing very rapidly, resulting in cloud computing’s popularity gain. Cloud computing provides ease of management of large amount of data and resources. With a lot of devices communicating over the Internet and with the rapidly increasing user demands, solitary clouds have to communicate to other clouds to fulfill the demands and discover services elsewhere. This scenario is called inter-cloud computing or cloud federation. Inter-cloud computing still lacks standard architecture. Prior works discuss some of the architectural blue-prints, but none of them highlight the key issues involved and their impact, so that a valid and reliable architecture could be envisioned. In this paper, we discuss the importance of inter-cloud computing and present in detail its architectural components. Inter-cloud computing also involves some issues. We discuss key issues as well and present impact of storage heterogeneity. We have evaluated some of the most noteworthy cloud storage services, namely: Dropbox, Amazon CloudDrive, GoogleDrive, Microsoft OneDrive (formerly SkyDrive), Box, and SugarSync in terms of Quality of Experience (QoE), Quality of Service (QoS), and storage space efficiency. Discussion on the results shows the acceptability level of these storage services and the shortcomings in their design.     

The optical characteristics in the layers of Compact Disc-Recordable

The optical characteristics of the laser beam in the layers of Compact Disc Recordable (CD-R) has been studied. The optical disk which is compatible with currently used CD-drive consists of transparent polycarbonate (PC) substrate, organic dye recording layer, reflective gold layer, and ultra-violet (UV) cured protecting layer. For proper design of the layer structure, modeling of the optical characteristics in each layer is necessary. The reflection and local absorption of the laser beam energy in the layers of the disk were numerically calculated. The reflection of the disk oscillates with the thickness of dye layer due to the interference in the multilayers. The oscillation magnitude and period depend on the complex refractive index of the material. The energy absorption profile in the recording layer is dependent on the thickness of the layer.     

Effect of Molecular Weight of Poly(Ethylene Glycol) Dicarboxylate on the Properties of Cross-Linked Hydrogel Film as an Antiadhesion Barrier

Poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) cross-linked hydrogel films were developed as an antiadhesion barrier using an e-beam. The effects of molecular weight of PEGDC on hydrogel properties were investigated. The decrease in molecular weight of PEGDC increased the gel fraction and tissue adhesion, whereas the mechanical strength did not change considerably. On the other hand, the swelling ratio decreased rapidly with decreasing molecular weight of PEGDC. The cytotoxicity of PEGDC (2000 or 3000) was low, whereas that of PEGDC (1000) was higher. In animal studies, all hydrogels showed a better antiadhesive effect compared to the control.     

Magnetic sensitivity enhanced novel fluorescent magnetic silica nanoparticles for biomedical applications

We synthesized novel fluorescent magnetic silica nanoparticles (FMSNPs) containing large magnetic components for biomedical application. By employing assemblies of magnetic nanoparticles as kernels against FMSNPs, both the saturation of magnetization and the magnetic resonance (MR) signal intensity were significantly enhanced. Furthermore, the cellular binding of FMSNPs was improved by introducing a positive charge on the surface of the FMSNPs, and fluorescent dyes on the surface of FMSNPs enable optical imaging of sub-cellular regions.     

Nanosurface-confined anisotropic growth and magnetism of ellipsoidal alpha-Fe nanogranules

We have investigated the nanosurface-confined anisotropic growth of ordered-ellipsoidal Fe nanogranules when an Fe plume was deposited at a slanting angle onto an anodized aluminum oxide (AAO) film. Layer-by-layer growth was also investigated. This growth is driven by two critical factors: (1) a new rhombic AAO cell and (2) the slanting deposition of the Fe plume. During slanting deposition, the rhombic AAO cell induces strong restrictions in the nucleation site, growth direction, and granular size; therefore, the degree of freedom during growth is restricted. The magnetic dipoles of the ordered Fe nanogranules are placed along the long axis of the ellipsoid at an angle of 180 degrees (antiparallel) due to the demagnetizing field, shape anisotropy, and magnetic dipole-to-dipole interactions.