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Lower-limb exoskeletons are promising applications of robotic rehabilitation for people with motor impairment. As current studies have tailored the design of gait trajectories for the target users, realizing a high-precision motion control is a critical issue for safe and effective assistance. The walking assistance involves unique characteristic phases that embody different physical constraints and requirements for assistance. Conventional methods often utilized gain-switching control for time-varying adaptation. However, despite their intuitiveness as well as simplicity, the control performance was unsatisfying due to unmodeled responses by human behavior and continuous interaction with the external environment. To tackle these challenges, this study proposes a hybrid control method applied to the disturbance observer that can provide robust robotic rehabilitation. The proposed method adaptively identifies the exoskeletal system as a hybrid nominal model and online exchanges model-based tracking controllers parallelly to the gait phase of a user. Furthermore, a unique filter named allowance filter is introduced to compensate for the plant dynamics, preventing instability of the inverted plant and realizing digital implementation. In this article, a practical user with complete paraplegia participated in the experiments for verification of the proposed methods. [ABSTRACT FROM AUTHOR]

Powered exoskeletons for people with complete paraplegia have been controlled based on predefined joint-reference trajectories. As the target users of such robots may not realize any voluntary movement, the human body is fully constrained and follows the movement of the powered exoskeleton joints. The predefined gait pattern, however, may or may not be adequate for every user because the gait pattern is resulting from complex interactions between the body segments and environment, as well as dynamic characteristics of the body segments. As all the persons and their body segments have different dynamic characteristics, therefore, a bespoke tuning of gait parameters is necessary in order to realize the natural gait motion, which is optimal for each user. In this article, an adaptive gait pattern adjustment method is proposed. The proposed method observes the ground contact timing, which is directly related to the adequacy of the gait pattern for the user wearing a robot. Based on the ground contact timing, the joint-reference trajectories are adjusted, which are parameterized by the trunk inclination angle. The proposed method iteratively calculates an appropriate trunk inclination angle from the information of ground contact timing. In this article, the derivation of the proposed method and its experimental verification with WalkON Suit, a powered exoskeleton, are introduced. The proposed algorithm successfully worked for two practical users with complete paraplegia, and the adapted gait patterns showed excessive performance in walking speed, oxygen consumption, palm force on crutches, etc. The results were also verified by winning both gold and bronze medals in the global competition, Cybathlon 2020, while accomplishing the best records among all the teams. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) was prepared by carbothermal reduction of a crystalline-layered sodium silicate (δ-Na2Si2O5)/carbon nanocomposite (LCN), which contained a stacked carbon film embedded with cobalt between the silicate layers. Subsequent sintering of this mixture for 3 h at 1000–1350°C resulted in the formation of graphitic carbon and SiC. Meanwhile, sintering without a cobalt catalyst resulted in the formation of graphitic carbon, regardless of the temperature. The use of a cobalt catalyst allowed the formation of a pure SiC phase at 1350°C. The formed SiC had an irregular worm-like morphology, with a particle size of ~5 µm. The Brunauer-Emmett-Teller surface areas of graphitic carbon and SiC were 28–150 and ~7.0 m2/g, respectively. We concluded that graphite and SiC were produced at this low sintering temperature because of the cobalt catalyst, which facilitated nanomixing of carbon and SiO2 by sandwiching the carbon films between the silicate layers. [ABSTRACT FROM AUTHOR]

Carboxylated-graphene–Mn2O3 (G-COOMn) nanocomposites were grown as Mn2O3 nanowires on graphene sheets by a one-step thermal method using graphene oxide–COOH (G-COOH) and Mn(NO3)2. Graphene oxide (G) was prepared by the Hummers method by using graphite flakes as a starting material. G-COOH sheets were synthesized using G and chloroacetic acid (Cl–CH2–COOH). G, G-COOH, and G-COOMn were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, 13C-nuclear magnetic resonance, and Raman spectroscopy. The electrochemical properties of the fabricated G-COOMn supercapacitor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. The obtained results showed that the asymmetric supercapacitor had electrochemical capacitance performance within the potential range 0–0.7 V. The supercapacitor delivered a specific capacitance of ∼300 F g−1 at a current density of 50 mA cm−2. The method used in this work provides an easy and straightforward approach for depositing Mn2O3 nanowires on graphene sheets and may be readily extended to the preparation of other classes of hybrids based on G sheets for use in specific technological applications. [ABSTRACT FROM AUTHOR]

Abstract: Carboxylated graphene–ZnO (G-COOZn) composites were grown as ZnO nanoparticles onto graphene sheets by a one-step thermal method using carboxylated graphene (G-COOH) and Zn(NO3)2. G-COOH sheets were synthesized from graphene oxide (GO) and chloroacetic acid (Cl–CH2–COOH). GO was used as the starting material, as prepared by the Hummers’ method using graphite flakes. GO, G-COOH, and G-COOZn were characterized by XRD, AFM, SEM, TEM, FT-IR, 13C-NMR, and Raman spectroscopy. The electrochemical properties of the G-COOZn supercapacitor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within the potential range of 0–1V. The supercapacitor delivered a specific capacitance of ∼238Fg−1 at a current density of 50mAcm−2. This method provides an easy and straightforward approach to deposit ZnO nanoparticles onto graphene sheets, and may be readily extended to the preparation of other classes of hybrids based on GO sheets for specific technological applications. [Copyright &y& Elsevier]

Abstract: Titanosilicate was modified by interlayer surface silylation using octyltriethoxysilane (OTES) and dodecylamine (DDA) in ethanol without a pre-swelling step. The introduction of silyl groups into the interlayer region was confirmed by XRD, FT-IR, RAMAN, SEM, TGA, 29Si NMR and TEM. DDA acts as a gallery expander and silylation catalyst. The evaporation of ethanol from the dispersion yields well-ordered silylation. Layered titanosilicate silicate with large basal spacings between 2.95 and 3.87nm were investigated. The layered structures of the silylated products were confirmed by swelling behavior upon attachment of alkylsilyl groups. Solid-state 29Si MAS NMR of the silylated samples showed Q3 and Q4 signals as well as T2 signals. The increase in the relative intensity of Q4 for Q3 and the appearance of a T2 signal was attributed to the grafting of OTES to the interlayer surface silanol groups. This method provides a promising route for the preparation of new functional nanomaterials to bond a variety of functional groups to the interlayer surface of layered materials. [Copyright &y& Elsevier]

Abstract: H+-titanosilicate (H4Ti2Si8O22 ·4H2O), formed by proton ion exchange of layered titanosilicate JDF-L1 (Na4Ti2Si8O22 ·4H2O) produced intercalation compounds in DDA (dodecylamine)–TEOS (tetraethylorthosilicate) solution. H+-titanosilicate/DDA/TEOS intercalation compounds rapidly hydrolyzed in pure water to form siloxane-pillared H+-titanosilicates. Calcination of siloxane-pillared H+-titanosilicates for 5h at 500°C in air resulted in the formation of mesoporous silica-pillared H+-titanosilicate (SPT) derivatives. SPT derivatives exhibited refractions corresponding to a basal spacing of 4.16–4.32nm, a uniform pore size of 2.8–3.4nm, and a large surface area of 535–618m2/g. The structures and physical properties of SPT derivatives remained stable after heating for 5h at 700°C in air. These results indicate that DDA molecules have a decisive role in pore formation within SPT derivatives, because they act as a base catalyst and as a template, like surfactant micelles, during the hydrolysis of TEOS. [Copyright &y& Elsevier]

Abstract: The new ion-selective electrodes (ISEs) based on salphenH2 derivatives such as N,N′-(propylenedioxy)benzenebis(salicylideneimine) L 1 and N,N′-4,5-(propylenedioxy)benzenebis(3,5-di-tert-butylsalicylideneimine) L 2 as cation carriers are developed for a uranyl ion. The combination of these new ionophores with tris(2-ethylhexyl)phosphate (TEHP) as a plasticizer particularly shows near Nernstian slope in the wide concentration range (1.0×10−6 to 1.0×10−2 M) of UO2 2+ and is observed well in the pH range from 1.0 to 5.0 with a response time less than 20s. Since the employed ionophores were confirmed to form well-defined stable 1:1 complexes with UO2 2+, the observed high selectivity for a uranyl ion over the other cations was attributed to the selective complexation as well as the lipophilic behavior of these ligands especially for L 2 . The proposed electrodes offered practically low detection limit of 6.5×10−7 M and reasonably good end-points within experimental error were obtained when the sensor was used as an indicator electrode for the potentiometric titration. [Copyright &y& Elsevier]

Mesoporous silica (MSPN12) was prepared by nonionic surfactant micelle–templated gelation of sodium silicate (Na2SiO3) and fluorosilicic acid (H2SiF6) in aqueous solution, characterized by a range of instrumental techniques, and tested as a support for Ni and Rh catalysts in the partial oxidation of methane (POM). Calcined and sintered MSPN12 exhibited well-defined d00l-spacings (3.5–4.39 nm), narrow pore distributions (2.4–3.1 nm), and large specific surface areas (552–1,246 m2 g−1), and was found to be highly thermally stable. Microscopic imaging revealed that MSPN12 comprised spherical particles with a uniform diameter of ~0.7 µm, with each particle featuring firm and regular honeycomb-type pores. MSPN12-loaded Ni and Rh maintained stable POM activity at 700 °C during almost 100 h on stream, which were comparable to those for the commercial Rh(5)/Al2O3 catalyst in terms of methane conversion and H2 formation selectivity. Thus, the combination of structural stability and favorable physicochemical properties resulted in good POM performance. [ABSTRACT FROM AUTHOR]

Mesoporous silica (MSPN12) was prepared by nonionic surfactant micelle–templated gelation of sodium silicate (Na2SiO3) and fluorosilicic acid (H2SiF6) in aqueous solution, characterized by a range of instrumental techniques, and tested as a support for Ni and Rh catalysts in the partial oxidation of methane (POM). Calcined and sintered MSPN12 exhibited well-defined d00l-spacings (3.5–4.39 nm), narrow pore distributions (2.4–3.1 nm), and large specific surface areas (552–1,246 m2 g−1), and was found to be highly thermally stable. Microscopic imaging revealed that MSPN12 comprised spherical particles with a uniform diameter of ~0.7 µm, with each particle featuring firm and regular honeycomb-type pores. MSPN12-loaded Ni and Rh maintained stable POM activity at 700 °C during almost 100 h on stream, which were comparable to those for the commercial Rh(5)/Al2O3 catalyst in terms of methane conversion and H2 formation selectivity. Thus, the combination of structural stability and favorable physicochemical properties resulted in good POM performance. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) was prepared by carbothermal reduction of a crystalline-layered sodium silicate (δ-Na 2 Si 2 O 5 )/carbon nanocomposite (LCN), which contained a stacked carbon film embedded with cobalt between the silicate layers. Subsequent sintering of this mixture for 3 h at 1000-1350°C resulted in the formation of graphitic carbon and SiC. Meanwhile, sintering without a cobalt catalyst resulted in the formation of graphitic carbon, regardless of the temperature. The use of a cobalt catalyst allowed the formation of a pure SiC phase at 1350°C. The formed SiC had an irregular worm-like morphology, with a particle size of ~5 µm. The Brunauer-Emmett-Teller surface areas of graphitic carbon and SiC were 28-150 and ~7.0 m 2 /g, respectively. We concluded that graphite and SiC were produced at this low sintering temperature because of the cobalt catalyst, which facilitated nanomixing of carbon and SiO 2 by sandwiching the carbon films between the silicate layers.

Background: We aimed to investigate mucosal immunity related to forkhead box P3 (FOXP3 + ) regulatory T (Treg) cells, T helper 17 (Th17) cells and cytokines in pediatric inflammatory bowel disease (IBD)., Methods: Mucosal tissues from terminal ileum and colon and serum samples were collected from twelve children with IBD and seven control children. Immunohistochemical staining was done using anti-human FOXP3 and anti-RORγt antibodies. Serum levels of cytokines were analyzed using a multiplex assay covering interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-17A/F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon (IFN)-γ, soluble CD40L, and tumor necrosis factor-α., Results: FOXP3 + Treg cells in the lamina propria (LP) of terminal ileum of patients with Crohn's disease were significantly ( P < 0.05) higher than those in the healthy controls. RORγt + T cells of terminal ileum tended to be higher in Crohn's disease than those in the control. In the multiplex assay, serum concentrations (pg/mL) of IL-4 (9.6 ± 1.5 vs. 12.7 ± 3.0), IL-21 (14.9 ± 1.5 vs. 26.4 ± 9.1), IL-33 (14.3 ± 0.9 vs. 19.1 ± 5.3), and IFN-γ (15.2 ± 5.9 vs. 50.2 ± 42.4) were significantly lower in Crohn's disease than those in the control group. However, serum concentration of IL-6 (119.1 ± 79.6 vs. 52.9 ± 39.1) was higher in Crohn's disease than that in the control. Serum concentrations of IL-17A (64.2 ± 17.2 vs. 28.3 ± 10.0) and IL-22 (37.5 ± 8.8 vs. 27.2 ± 3.7) were significantly higher in ulcerative colitis than those in Crohn's disease., Conclusion: Mucosal immunity analysis showed increased FOXP3 + T reg cells in the LP with Crohn's disease while Th17 cell polarizing and signature cytokines were decreased in the serum samples of Crohn's disease but increased in ulcerative colitis., Competing Interests: Disclosure: The authors have no potential conflicts of interest to disclose.

Mesoporous silica-pillared H(+)-kenyaite (SPK) derivatives with highly ordered gallery structure and thermal resistance were prepared by the hydrolysis of TEOS (tetraethylorthosilicate) in interlayer space, using DDA (dodecylamine) as catalyst and template. DDA-TEOS/H(+)-kenyaite intercalation compounds were obtained by the dispersion of H(+)-kenyaite in DDA-TEOS solution. DDA-TEOS/H(+)-kenyaites were hydrolyzed rapidly in pure water, forming siloxane pillared H(+)-kenyaites. Calcination of siloxane pillared H(+)-kenyaites for 5 h at 600 degrees C in air resulted in mesoporous SPK derivatives. These exhibited refractions corresponding to a basal spacing of 5.0-5.5 nm, a uniform pore size of 2.5-3.0 nm and large surface areas between 707 and 877 m2/g. TEM images confirmed that SPK had uniform interlayer spaces of 2.0-3.0 nm in agreement with the gallery height and pore size data. The structure and physical properties of SPK remained stable after heating for 5 h at 800 degrees C in air. This is attributed to the stable structure of kenyaite composed of 4-fold SiO4 tetrahedral sheets, and the formation of firm silica pillars.