Highly stretchable,self-adhesive,and self-healable double network hydrogel based on alginate/polyacrylamide with tunable mechanical properties

A number of synthetic hydrogels suffer from low mechanical strength. Despite of the recent advances in the fabrication of tough hydrogels, it is still a great challenge to simultaneously construct high stretchability, and self-adhesive and self-healing capability in a hydrogel. Herein, a new type of double network hydrogel was prepared based on irreversible cross-linking of polyacrylamide chains and Schiff-base reversible cross-linking between glycidyl methacrylate-grafted ethylenediamine and oxidized sodium alginate (OSA). The combination of both cross-linkings and their synergistic effect provided a novel hydrogel with high strength, stretchable, rapid self-healing, and self-adhesiveness to different material. Besides, the hydrogels with diverse OSA content could maintain their original shapes after loading–unloading tensile test. The resulting hydrogel has a great potential in various fields for supporting and load-bearing substance.     

Fabrication,controlled release,and kinetic studies of indomethacin—layered zinc hydroxide nanohybrid and its effect on the viability of HFFF2

The intercalation of indomethacin into the interlayer gallery of layered zinc hydroxide (LZH) has been successfully executed using the simple ion exchange approaches. The synthesized intercalation compound, indomethacin-LZH nanohybrid, was characterized using PXRD, FTIR, SEM, BET, and STA. From the PXRD results, the intercalation of indomethacin anions into the interlayer gallery of LZH was successful; showing the formation of a new peak at lower 2θ with a basal spacing of 21.96?Å. FTIR analysis of the nanohybrid further supported the presence of indomethacin in the interlayer of the indomethacin-LZH nanohybrid. STA analysis confirms that the nanohybrid has higher thermal stability than pure indomethacin. The in vitro release mechanism of the indomethacin anions from the indomethacin-LZH nanohybrid showed slow release, with 95% and 78% release in phosphate buffer saline (PBS) solution at pH 4.8 and 7.4, respectively. The release behavior of indomethacin from its intercalation compounds in PBS solution at pH 4.8 and 7.4 follows the Higuchi model. In addition, the nanohybrid treated with normal fibroblast cell line shows that it reduces cell viability in a dose and time-dependent manner. This study shows that the high potential of the nanohybrid as an encapsulated material for the controlled release formulation of nonsteroidal anti-inflammatory (NASID) anions.     

Synthesis of 2-Mercaptonicotinic Acid-Capped CdSe Quantum Dots and its Application to Spectrofluorometric Determination of Cr(VI) in Water Samples

The CdSe quantum dots (QDs) capped with 2-mercaptonicotinic acid (H₂MN) were prepared through a controllable process at 80 °C. The prepared QDs were characterized by XRD, TEM, IR, UV–Vis and fluorescence (FL) techniques. It was found that the QDs were nearly mono-disperse with the diameters in the range of 8–10 nm. These QDs are capable to exhibit strong FL even in concentrated acidic media. They exhibit an enhanced fluorescence in the presence of Cr(VI), which was used for the determination of Cr(VI) in water samples. The linear range was found to be 1?×?10^?7–6.0?×?10^?6 M with the RSD and DL of 0.92 % and 5?×?10^?8 M, respectively. Except that Ca²⁺ and Fe³⁺ which can be eliminated through a simple precipitation process, the other co-existent ions present in natural water were not interfered. The recoveries obtained for the added amounts of Cr(VI) were in the range of 96.9–103.2 %, which denote on application of the method, satisfactorily.     

Modification of poly(ethylene terephthalate) fibers,fabrics, and films by amination reactions—A review

Currently, many of our living facilities are dependent on poly(ethylene terephthalate) (PET). It is utilized in the production of textiles, beverage bottles, food packaging, implants, and so forth. Although PET has desirable properties, it has to be amended for certain applications that have been modified by different methods. For modifications, aminolysis is used by several investigators, and this report reviews critically the related literature. Amines can be applied to impart the desired properties and produce active sites to be used for further alterations by successive reactions. Amine treatments alone enhance wettability, increase dyeability, and most applicable, produce functionality on the surface. By further reactions with several other chemicals, a spectrum of properties was endowed to PET products, such as flame retarding, anti-fouling property, highest hygroscopicity, silk-like character, biocompatibility, and so forth. There are a large number of works, mainly to change the surface properties, but the literature on the in vivo or common everyday evaluation of the amended products is scarce. Most of the modifications of PET products by amines are accompanied by a decrease in some other properties. Then the process of aminolysis and modifications have to be optimized with respect to several production parameters.     

Thermoelectric Properties of High-Entropy Wolframite Oxide: (CoCuNiFeZn)1−xGaxWO4

Herein, the synthesis of high-entropy wolframite oxide (CoCuNiFeZn)_1-xGaxWO₄ through standard solid-state route followed by spark plasma sintering and their structural, microstructural, and thermoelectric (TE) properties are investigated. X-ray diffraction pattern followed by patterns matching refinement shows a monoclinic structure with the volume of the unit cell decreasing with increasing Ga content. The optical bandgap for these oxides shows a cocktail effect in high-entropy configuration. The Seebeck coefficient indicates electrons as dominating charge carriers with a nondegenerate behavior. The electrical resistivity decreases with increasing temperature depicting a semiconducting nature. Thermal conductivity in high-entropy samples (κ ≈ 2.1 W m⁻¹ K⁻¹ @ 300 K) is significantly lower as compared to MgWO₄ (κ ≈ 11.5 W m⁻¹ K⁻¹ @ 300 K), which can be explained by the strong phonon scattering due to large lattice disorder in high-entropy configuration. The TE figure of merit zT increases with Ga doping via modifying all three TE parameters positively.     

Novel optical polarizer design based on metasurface nano aperture for biological sensing in mid-infrared regime

Since Metasurfaces are playing important roles in optical devices such as optical polarizers and detectors, in this article, we have proposed a novel shape of nano aperture antenna for mid-infrared applications such as bio-sensing and other potential optical applications based on plasmonic characteristic of the gold layer over the SiN substrate. The transmittance tensor is obtained for vertical and horizontal linear polarization and base on boundary condition of the metasurface, the circular polarizations are extracted which are confirmed by the electric field distributions. We have shown by the parametric studies that the phase difference is altered by the gap and slot width and so with the dimension modification, we are able to achieve circular polarizer in the optical range. The biological materials with a thickness of 80 nm have then been placed over the metasurface layer and the figures of merits have been obtained. We have revealed that when the circular polarization is osculated to the metasurface at a special frequency the linear polarization is obtained in the other side of the metasurface. The nano aperture has been modeled and the finite difference time domain calculations are performed in CST Microwave Studio as a commercial full wave simulation software.     

Output feedback controller for hysteretic time-delayed MIMO nonlinear systems

In this paper, an H ^?? output feedback controller is developed for a class of time-delayed MIMO nonlinear systems, containing backlash as an input nonlinearity. Particularly, a state observer is proposed to estimate unmeasurable states. The control law can be divided into two elements: An adaptive interval type-2 fuzzy part which approximates the uncertain model. The second part is an H ^??-based controller, which attenuates the effects of external disturbances and approximation errors to a prescribed level. Furthermore, the Lyapunov theorem is used to prove stability of proposed controller and its robustness to external disturbance, hysteresis input nonlinearity, and time varying time-delay. As an example, the designed controller is applied to address the tracking problem of 2-DOF robotic manipulator. Simulation results not only verify the robust properties but also in comparison with an existing method reveal the ability of the proposed controller to exclude the effects of unknown time varying time-delays and hysteresis input nonlinearity.     

Intelligent wireless mesh path selection algorithm using fuzzy decision making

Wireless mesh networks (WMNs) are expected to be widely deployed due to their ability to provide ubiquity, convenience, cost-efficiency, and simplicity for both service providers and end-users. Recently, the IEEE 802.11s standard introduces the hybrid wireless mesh protocol (HWMP) which is inspired by a combination of on-demand and tree-based pro-active routing algorithms. In this paper, we argue that the proposed unimetric path selection algorithm in the standard is not reliable. We introduce and examine a novel multimetric wireless mesh path selection algorithm using fuzzy decision making under realistic wireless channel conditions. The proposed path selection algorithm is designed to improve the performance of both re-active and pro-active routing protocols of HWMP for not only single-channel but also multi-channel WMNs. The reported results show the superior performance of the proposed path selection algorithm in terms of delay and packet delivery ratio without increasing overhead significantly. Although some fuzzy-based routing algorithms have been defined in literature recently, to the best of our knowledge, this paper is the first one to introduce and examine the use of fuzzy logic in the path selection of single- and multi-channel wireless local area network-based WMNs under realistic wireless channel conditions.     

Robotic ICSI (intracytoplasmic sperm injection)

This paper is the first report of robotic intracytoplasmic sperm injection (ICSI). ICSI is a clinical procedure performed worldwide in fertility clinics, requiring pick-up of a single sperm and insertion of it into an oocyte (i.e., egg cell). Since its invention 20 years ago, ICSI has been conducted manually by a handful of highly skilled embryologists; however, success rates vary significantly among clinics due to poor reproducibility and inconsistency across operators. We leverage our work in robotic cell injection to realize robotic ICSI and aim ultimately, to standardize how clinical ICSI is performed. This paper presents some of the technical aspects of our robotic ICSI system, including a cell holding device, motion control, and computer vision algorithms. The system performs visual tracking of single sperm, robotic immobilization of sperm, aspiration of sperm with picoliter volume, and insertion of sperm into an oocyte with a high degree of reproducibility. The system requires minimal human involvement (requiring only a few computer mouse clicks), and is human operator skill independent. Using the hamster oocyte-human sperm model in preliminary trials, the robotic system demonstrated a high success rate of 90.0% and survival rate of 90.7% (n=120).     

Does shape matter? Bioeffects of gold nanomaterials in a human skin cell model

Gold nanomaterials (AuNMs) have distinctive electronic and optical properties, making them ideal candidates for biological, medical, and defense applications. Therefore, it is imperative to evaluate the potential biological impact of AuNMs before employing them in any application. This study investigates two AuNMs with different aspect ratios (AR) on mediation of biological responses in the human keratinocyte cell line (HaCaT) to model potential skin exposure to these AuNMs. The cellular responses were evaluated by cell viability, reactive oxygen species (ROS) generation, alteration in gene and protein expression, and inflammatory response. Gold nanospheres, nominally 20 nm in diameter and coated with mercaptopropane sulfonate (AuNS-MPS), formed agglomerates when dispersed in cell culture media, had a large fractal dimension (D(f) = 2.57 ± 0.4) (i.e., tightly bound and densely packed) and were found to be nontoxic even at the highest dose of 100 μg/mL. Highly uniform, 16.7 nm diameter, and 43.8 nm long polyethylene glycol-capped gold nanorods (AuNR-PEG) also formed agglomerates when dispersed into the cell culture media. However, the agglomerates had a smaller fractal dimension (D(f) = 1.28 ± 0.08) (i.e., loosely bound) and were found to be cytotoxic to the HaCaT cells, with a significant decrease in cell viability occurring at 25 μg/mL and higher. Moreover, AuNR-PEG caused significant ROS production and up-regulated several genes involved in cellular stress and toxicity. These results, combined with increased levels of inflammatory and apoptotic proteins, demonstrated that the AuNR-PEG induced apoptosis. Exposure to AuNS-MPS, however, did not show any of the detrimental effects observed from the AuNR-PEG. Therefore, we conclude that shape appears to play a key role in mediating the cellular response to AuNMs.