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An ionic cascade insertion/cyclization reaction of thia-/selena-functionalized arylisocyanides has been successfully developed for the efficient and practical synthesis of 2-halobenzothiazole/benzoselenazole derivatives. This synthetic protocol, incorporating a halogen atom when forming the five-membered ring of benzothia/selenazoles, is different from the existing ones, where halogenation of the preformed benzothia/selenazole precursors happens. Additionally, a facile access to 2-aminobenzothiazoles is also achieved by the one-pot cascade reaction of 2-isocyanoaryl thioethers, iodine, and amines.

Flexible pressure sensors with high sensitivity have great potential applications in wearable electronics. However, it is still a great challenge to prepare sense electrodes with high flexibility, high sensitivity, and high electrochemical performance. Here, we propose a novel and simple method for carbonizing cotton fibers as excellent electrically conductive materials. Moreover, carbonized cotton fiber (CCF) and polydimethylsiloxane (PDMS) were assembled into a flexible sense electrode. The CCF/PDMS electrode shows a high sensitivity of 10.8 kPa−1, a wide response frequency from 0.2–2.0 Hz, and durability over 900 cycles. The combined CCF/PDMS sensors can monitor human movement and pulse vibration, showing the enormous potential for use in wearable device technology. Additionally, the CCF/PDMS can be used as electrodes with a specific capacitance of 332.5 mF cm−2 at a current density of 5 mA cm−2, thanks to their high electrical conductivity and hydrophilicity, demonstrating the promising prospect of flexible supercapacitors.

Cotton is an inexpensive natural product, which is mainly composed of cellulose fibers. Here, based on carbonized cotton fibers as substrates, we report a simple and facile method for the fabrication of a modified porous graphene hydrogel electrode. The method involved addition of 1,5-diaminoanthraquinone (DAQ) onto graphene to obtain a decorated graphene hydrogel electrode. DAQ is uniformly anchored on graphene sheets by π–π interactions. A robust and flexible DAQ–CGH hydrogel electrode is prepared by a hydrothermal method and optimized through different mass ratios. The carbonized cotton fiber substrate guarantees high mechanical strength, meanwhile the conductive graphene sheets serve as an electron transport medium for DAQ to ensure its remarkable pseudocapacitance. The DAQ–CGH composite exhibits a high specific capacitance of 490.2 F g−1 at 1 A g−1 with a stable capacity retention of 89.93% after 10 000 cycles at 5 A g−1 and excellent mechanical flexibility (about 92.15% of its original capacitance after 1000 bending cycles). Moreover, the assembled DAQ-2-CGH SCs achieve a high energy density of 36.18 W h kg−1 and power density of 2145.53 W kg−1.

A flexible film electrode composed of sodium carboxymethyl cellulose (CMC), polypyrrole (PPy) and reduced graphene oxide (RGO) was designed by in situ polymerization and vacuum filtration. The obtained film displayed CMC–PPy nanospheres wrapped in an RGO framework, resulting in a free-standing and highly flexible supercapacitor electrode. The incorporation of hydrophilic CMC into the film enhanced the diffusion paths of electrolyte ions and prevented the volume deformation of PPy during the long-term charging/discharging. Furthermore, PPy provided a large pseudocapacitance and RGO endowed the film electrode with prominent flexibility. The remarkable interaction between CMC, PPy and RGO achieved a synergistic effect on the structural stability and electrochemical performance of the film electrode. When the mass ratio of CMC–PPy to RGO was 1 : 1, the highest specific capacitance of the sodium carboxymethyl cellulose–polypyrrol@reduced graphene oxide (S-CPR1 : 1) was 489 mF cm−2 (191 F g−1) with a mass of 2.56 mg cm−2 at a current density of 0.5 mA cm−2. And the area specific capacitance of the S-CPR1 : 1 electrode could remain as 101.6% of the original value after 1000 charge/discharge cycles, which was higher than the polypyrrol@reduced graphene oxide (S-PR) electrode (72.4%) prepared under the same conditions. Besides, the S-CPR1 : 1 electrode exhibited remarkable flexibility with 95.6% capacity retention after 500 fold cycles. These above results indicated that the S-CPR1 : 1 film electrode provided a simple way of developing free-standing and flexible electrode materials for next-generation electrochemical electrodes.

Designing flexible supercapacitors (FSCs) as energy storage devices for portable/wearable electronic products using the earth-abundant, renewable and environmentally friendly natural biomass has the prospect of building a green, sustainable society. Here, we report a new type of three-dimensional graphene hydrogel with lignin-based nitrogen-doped carbon dots as a decorative material. The nitrogen doped carbon dots are anchored in a graphene sheet through π–π bonds and electrostatic interactions, forming a stable three-dimensional network structure, which comprehensively improves the electrochemical performance of the electrode material. As an electrode, the specific capacitance reaches 387 F g−1 at 1 A g−1, and the rate performance reaches 75.7% when the current density increases to 7 A g−1. In addition, an all-lignin-based supercapacitor assembled with a lignin hydrogel as the electrolyte has superior cycle stability (cycle life after 5000 cycles is 92.3%) and rate performance. When the power density is 243 W kg−1, the energy density is 25.6 W h kg−1; moreover, the FSC has excellent electrochemical stability even at different bending angles. This all-lignin-based FSC with excellent electrochemical performance and flexibility opens up a new path for the application of lignin in flexible energy storage devices.

Cellulose aerogels (CA) have been used in widespread areas, such as absorbents, thermal insulation material and medical material. Herein, a robust strategy to fabricate cellulose aerogels by combining cellulose nanofibers with PVA “glue”. The CA not only had a robust chemical-bond cross-link network, but also had a strong H-bond, which enhanced underwater mechanical properties. Moreover, the compressible CA provided a large number of nucleation sites for the growth of Metal-organic frame (MOF) nanoparticles (ZIF-67 and ZIF-8) through interface self-assemble. The obtained aerogels with a low density of 9.8-11.2 mg cm -3 and highly porous of 99.4-99.5% possessed excellent mechanical properties both in air and underwater. The adsorption capacities of the MOF@CA for Pb 2+ and Cu 2+ are up to 105.21 mg g -1 and 54.78 mg g -1 , respectively. The novel MOF@CA adsorbents with excellent mechanical properties display application prospects in the removal of heavy metals from wastewater.

A novel tannic acid–reduced graphene oxide (TAG) composite absorbent was prepared by using a simple one-step method. The prepared TAG was characterized by various analytical techniques including FTIR, Brunauer–Emmett–Teller (BET), scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Tannic acid (TA) not only can prevent graphene sheets from agglomerating by suppressing the hydrophobic stacking interactions but also can introduce a large number of phenol hydroxyls. The adsorption studies indicate that the TAG composite showed an excellent uptake capacity (179.22 mg/g) for Cr(VI) under the optimized conditions (viz., adsorbent dosages of 0.75 g/L, solution pH of 2.5, contact time of 360 min, and temperature of 60 °C), which is higher than that of most graphene oxide– and TA-based adsorbents. The BET specific surface area of TAG was calculated to be 118.3 m2/g; the pore diameter of Tannin acid-reduced graphene hydrogel (TAGH) was mainly 3–6 nm, with pore size peak at 5.0 nm. The kinetics of Cr(VI) adsorption on TAG followed the pseudo-second-order model. The isotherm studies confirmed that the Cr(VI) chemically adsorbed on TAG in a monolayer fashion, which was attributed to the electrostatic interaction between chromium ions and oxygen negative ions. The process of Cr(VI) adsorption was found to be thermodynamically spontaneous and endothermic.

A novel composite electrode has been fabricated by the direct deposition of MnO2 onto graphene networks surrounding a paper fiber (PFG). The paper fiber between graphene sheets could be used as a flexible substrate for MnO2 nanoparticles, and the microscopic morphologies and electrochemical performances of the MnO2@PFG electrodes were tuned via regulating the deposition current densities and deposition times. 3D graphene on PFG served as a highly conductive backbone with a high surface area for the deposition of the MnO2 nanoparticles, which provided high accessibility to electrolyte ions for shortening the diffusion paths. The MnO2-10-600 s@PFG composite electrode achieved a maximum specific capacitance of 878.6 mF cm−2 with an MnO2 loading mass of 3.62 mg cm−2 (specific capacitance of 187.7 F g−1) at a current density of 0.5 mA cm−2 in a 1 M NaSO4 aqueous solution. Additionally, the MnO2-10-600 s@PFG composite material with the most favorable composite ratio exhibited the highest energy density of 61.01 mW h cm−2, maximum power density of 1249.78 mW cm−2, excellent capacitance retention with no more than 7% capacitance loss after 10 000 cycles and good mechanical flexibility (about 91.06% of its original capacitance after 500 bending times). By combining the electric double layer capacitance of graphene networks with the pseudocapacitance of the MnO2 nanostructures, the flexible electrode showed much enhanced electrochemical capacitance behaviors with robust tolerance to mechanical deformation; thus, it is promising for being woven into textiles for wearable electronics.

Amino group protective strategy has consequently emerged in multistep organic synthesis. Easy and selective deprotection procedures are crucial to facilitate the chemical transformation. Recently, Zhang’s group from Henan Normal University collaborating with Chen’s group of Nankai University developed a novel strategy for the regiospecific cleavage of inert aryl C N bonds in N-aryl amides by hypervalent iodine(V) reagents. These procedures allow removal of sort of aryl groups under mild conditions to give primary amides in high efficiency. It bestows these aryl groups with the characteristics of amino protecting groups that might be the supplement of amino protecting group chemistry.

NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3)-induced pyroptosis is involved in the development of a variety of autoimmune diseases, but its role in IgG4-related sialadenitis (IgG4-RS) is unclear.Salivary gland tissues from 19 patients with IgG4-RS were designated the experimental group, and peritumoral tissues from 20 patients with benign salivary gland tumours were designated the control group. The cell morphology and fibrosis in the IgG4-RS samples were observed by haematoxylin-eosin (HE) and Masson trichrome (MT) staining. Immunohistochemical (IHC) staining was used to determine pyroptosis-related proteins (NLRP3, ASC (apoptosis-associated speck-like protein containing a CARD), Caspase-1, GSDMD (gasdermin family members, including digestive dermatin D), interleukin 1β (IL-1β), and interleukin 18 (IL-18)) expression levels.Increased lymphoid follicle proliferation, germinal centre plasma cell infiltration, and irregular fibrosis were observed in the experimental group compared with the control group. The NLRP3, ASC, Caspase-1, GSDMD, IL-1β, and IL-18 levels were significantly higher in the experimental group than in the control group (p 0.0001).This study suggested that pyroptosis-related proteins might be involved in IgG4-RS pathogenesis. However, the specific cellular pathway involved and whether multiple cell death pathways contribute to the occurrence of IgG4-RS still need to be further studied.

Flexible supercapacitors (FSCs) have attracted widespread attention of many researchers as a type of portable energy storage devices. However, there are still challenges in preparing renewable and ...

MnO2 nanoparticles with high theoretical capacitance were successfully synthesized on a reduced graphene oxide/lignin-based porous carbon (RGO/PC) composite membrane by a simple electrodeposition method, and a ternary RGO/PC/MnO2 composite electrode for flexible supercapacitors was prepared. The RGO/PC/MnO2-1200s composite electrode exhibited a maximum specific capacitance of 1136 mF cm−2 (MnO2 mass loading of 6.25 mg cm−2 and a mass specific capacitance of 135 F g−1) at a current density of 1 mA cm−2. This is attributed to the high surface area of the MnO2 nanoparticles and the conductive pathway provided by the RGO/PC framework. The assembled flexible solid-state symmetric supercapacitors have outstanding cycling stability (approximately 85.2% capacitance retention after 5000 cycles) and good mechanical flexibility (about 87.6% of the original capacitance after 500 bending cycles). Importantly, the device can possess a maximum energy density of 0.253 mW h cm−3 at 0.5 mA cm−2 and a maximum power density of 0.018 W cm−3 at 5 mA cm−2. The results above indicate that the RGO/PC/MnO2 composite has potential applications in flexible energy storage devices.

A simple and template-free method for the fabrication of modified pulp fiber (PF)–polyacrylamide (PAM)–graphene (RGO) composite electrodes was developed. The pulp fiber–graphene electrodes decorated with polyacrylamide were synthesized via a facile vacuum-filtration process, and further optimized through different mass ratios. Benefiting from the porous structure and large amounts of hydrophilic groups in the paper fiber, the PF–PAM–RGO composite electrode demonstrated good hydrophilic property and ion transport capacity within the electrode. After adding the polyacrylamide molecule (PF–RGO), the PF–PAM–RGO composite electrode exhibited good mechanical properties and capacitance performance due to PF–RGO hydrogen bonding. Moreover, the PF–PAM–RGO composite electrode displayed a high area specific capacitance of 498.4 mF cm−2 with a mass of 2.32 mg cm−2 (specific capacitance of 214.8 F g−1) at 0.2 mA cm−2. The assembled PF–PAM–RGO composite electrode showed a good cycling stability (92.36% capacitance retention after 8000 charging/discharging cycles) and mechanical flexibility (87.65% capacitance retention after 500 bending/unbending cycles). Remarkably, the flexible device could achieve superior energy density of 80.59 μWh cm−2 and high power density of 2549.83 μW cm−2.

Although the content of science lessons has been analyzed from different perspectives by developing a set of codes (e.g., K. J. Roth, S. L. Druker, H. E. Garnier, M. Lemmens, C. Chen, T. Kawanaka, and R. Gallimore, (2006), Teaching science in five countries: results from the TIMSS 1999 video study, Washington, DC: National Center for Education Statistics), none of the existing coding systems have investigated it from a subject-specific and dynamic perspective. Aiming to fill this gap, this study develops a content coding map (CCM) to classify the content of chemistry lessons (CCL) into 12 types based on their roles and values. The CCM was constructed based on semi-structured interviews and revised by applying the initial CCM to six videotaped lessons. Furthermore, the coding was reviewed by an expert committee to confirm the content validity and evaluated by 86 in-service teachers using a questionnaire with responses measured on a five-point Likert scale to test for face validity. These 12 types of CCL were organized into five related groups in the CCM: core knowledge and practices (CKP), connections among CKP (C-CKP), expansion of CKP (E-CKP), scaffolding for CKP (S-CKP), and meaningless content in relation to CKP (MC-CKP). Each group is illustrated and discussed using specific types of CCL. The CCM, which provides a new way to explore chemistry classrooms, can be used as an analytic tool for chemistry educators to investigate the CCL and can serve as a guide for chemistry teachers when designing lessons.

Coupling electroactive species with carbon substrates to synthetize composite electrodes holds great promise for obtaining excellent supercapacitors. However, the poor bonding between the carbon supports and the electroactive species is still a bottle-neck to be addressed. Herein, we report a rational design and fabrication of NiCo2Se4 supported on tannin-doped activated carbon by employing tannin as the structure coupling bridge between the two components, which effectively tunes the electronic structural states and results in strong coupling effects with NiCo2Se4. Benefiting from the structural characteristics, the as-obtained N-doped activated carbon–tannin–NiCo2Se4 (NAC–TA–NCS) composites, especially, the NAC–TA–NCS 10 : 1 hybrids (the mass ratio of NAC–TA–NCS to tannin is 10 : 1) deliver the best electrochemical properties. The NAC–TA–NCS 10 : 1 electrode shows the highest specific capacitance value (1262 F g−1 at 0.5 A g−1, 1060 F g−1 even at 30 A g−1), excellent rate property, and outstanding cycling stability (95.095% of the initial value after 10 000 cycles at 5 A g−1). Meanwhile, the as-obtained NAC–TA–NCS 10 : 1//AC could achieve a high energy density of 78.19 W h kg−1 at the power density of 0.859 kW kg−1 at 50 A g−1 as well as the outstanding cycling stability with 97.35% of the initial value after 10 000 cycles. The work exhibits that the NAC–TA–NCS hybrids are promising electrode materials for energy storage. The hydrophilic strategy could be extended to assemble other kinds of active species on different supports, and holds potential for achieving effective and robust electrode materials for energy-related devices.

Articular cartilage defects and degeneration can be caused by multiple factors, and the current clinical treatment schemes for pathological changes are relatively limited. Engineered cartilage tissue represents an alternative therapy for repairing cartilage defects in regenerative medicine. The scaffold material is considered the framework of tissue engineering; thus, scaffold material selection plays a crucial role in the therapy outcome. Polycaprolactone (PCL)-hydroxyapatite (HA) has been applied as a scaffold material for bone and cartilage tissue engineering with nontoxic, harmless metabolites and proper physical properties. The extracellular matrix (ECM) is mainly composed of collagen and proteoglycan, as well as a large number of growth factors and cytokines, which provide a tissue-specific microenvironment for host cells. Adipose-derived stem cells are pluripotent stem cells, and transforming growth factor-β3 (TGF-β3) enables mesenchymal stem cells to promote ECM production. This study, via

The aim of this paper was to investigate the clinical and magnetic resonance imaging (MRI) features of synovial chondromatosis (SC) of the temporomandibular joint (TMJ). Fourteen patients with SC of the TMJ were included in the study. Clinical and MRI features were analysed and divided into three types based on MRI classification: type I with loose bodies, type II with homogeneous masses, and type III with a mixture of loose bodies and homogeneous masses. All SCs occurred in the superior compartment of the TMJ. There were two patients (14%) categorised as type I, five (36%) as type II and seven (50%) as type III. Four patients (29%) had disc perforation, and nine had bone erosion; among those nine, seven (78%) had type III and two (22%) type II. Histological examination showed inflammation and calcification in the synovial membrane and, and cartilage of the hyaline type in all cases. MRI has advantages in the diagnosis of SC.

Background: Pyroptosis is the highlight topic in inflammation. However, there is rarely research on relationship between pyroptosis and temporomandibular joint osteoarthritis (TMJOA), The aim of this study is to explore whether pyroptosis related molecules are significant for condylar cartilage degeneration and to verify the clinical effects of sodium hyaluronic acid (HA) treatment on TMJOA.Methods: Patients diagnosed as temporomandibular joint internal derangement (TMJID) without condylar defect and TMJOA with condylar defect were divided into two groups. Thirty patients in each group, and they were tested for pyroptosis related molecules via synovial fluid included interleukin-1beta (IL-1β), IL-18, nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3), cysteinyl aspartate specific proteinase 1 (CASP1) with Enzyme-linked immunosorbent assay（Elisa）. Eighteen cases in TMJOA group were tested again after twice HA treatment to evaluate HA’s therapeutic effects. Results: IL-1β, IL-18, NLRP3 and CASP1 were all positive in two groups, TMJOA patients with condylar defect had higher expressions of above molecules compared with TMJID patients (P＜0.05). IL-1β, IL-18, NLRP3 were decreased with twice HA therapy (P＜0.05), there was no significant difference in CASP1 with twice HA injections (P=0.549). Conclusions: Cell pyroptosis may be involved in condylar degeneration. HA could reduce part of pyroptosis molecules to relieve inflammation.

Poplar wood pulp was adopted as both frame and precursor for the synthesis of pulp fiber (PF)/reduced graphene oxide composite via a simple and low-cost method. In this method, the PF based on graphene (PFG) composite film electrode was prepared by a simple vacuum filtration process with various ratios (PF: reduced graphene oxide (RGO) = 5:1, PF:RGO = 5:2, PF:RGO = 5:3, PF:RGO = 5:4, PF:RGO = 5:5). In terms of special structures, the PFG can be used as electrodes without metal-collector, adhesives, and additives. The optimal ratio (PF:RGO = 5:4) film electrode displayed a high areal-specific capacitance of 683 mF/cm² at 1 mA/cm² with a mass of 5.3 mg/cm² (specific capacitance of 129 F/g) and good cycling stability (87.5% capacitance retention after 10,000 cycles at 5 mA/cm²) as well as excellent rate capability and high flexibility (suitable for any angle, even 180°). Moreover, the device could possess a maximum energy density of 47.71 μWh/cm² and a maximum power density of 1251 μW/cm². These results suggest that the composite PGF film is a promising electrode material.

Pectin, natural polysaccharide biopolymer, was chelated with cations (Mg2+/Ca2+) to form an interwoven framework. Herein, the graphene hydrogel electrodes were self-assembled by the synergistic effects of pectin-cations. The optimum combination proportion was determined, the Mg2+/Ca2+-pectin matrix cross-linked graphene hydrogel (Mg2+/Ca2+-PGH) electrodes exhibited a large specific capacitance of about 839.2 F g−1 with high coulombic efficiency of 191.8% at a current density of 1 A g−1. The assembled flexible supercapacitor displayed excellent stability (capacitance retention of 98.5% after 2000 charge/discharge cycles) and flexibility (the specific capacitance remained 98.4% of its original value after 500 folding/unfolding cycles). Such flexible and high-performance Mg2+/Ca2+-PGH electrodes are attractive in the field of lightweight, miniature and wearable energy storage devices.

A simple and low-cost approach toward flexible and free-standing electrodes is developed. Ternary composites of graphene/carbonized paper/tannic acid (GN/CP/TA) with various ratios were fabricated via a facile vacuum-filtration process. Through carbonization of widely used paper, the obtained carbonized paper possessed a good pore structure and an ion transport channel. Tannic acid (TA) can enter into the layers of graphene sheets and prevent graphene sheets from agglomerating by suppressing the π–π stacking interactions. Different amounts of tannic acid increased the distance between graphene sheets, facilitating the formation of GN/CP/TA composite electrodes without metallic current collectors, binders and additives. The optimal ratio (GN/CP/TA2) was determined and the composite electrodes displayed a high area specific capacitance of 530.2 mF cm−2 with a mass of 2.85 mg cm−2 (specific capacitance of 186 F g−1) at 0.2 mA cm−2. The composite electrode had good mechanical flexibility (about 82.94% retention in capacitance after 500 bending times) and prominent cycling stability (86.62% retention in capacitance over 10 000 cycles). Moreover, the device can achieve a superior energy density of 36.82 μW h cm−2 and a maximum power density of 1372.73 μW cm−2. These results demonstrated that the composite film was a promising electrode material and may be useful for the development of flexible high-performance and wearable energy storage devices. More importantly, this strategy provided a facile method for the fabrication of other types of composite film electrodes.

The idiopathic condylar resorption (ICR) is a kind of disease with severe bone damage to the temporomandibular joint condylar process. ICR high misdiagnosis rate based on the similarities in symptoms and imaging manifestations with temporomandibular joint osteoarthritis (TMJOA). To provide key points for the accurate diagnosis of ICR and TMJOA. Here we show that the number of malocclusion factors and imaging findings in the TMJOA group has significant differences from statistics in the ICR group. We found that the ICR patients might have no oral side function or bad chewing habits without joint noising and mostly with the planar profile of condyle apex and poor subchondral bone continuity after bone resorption. Our results demonstrate key points for a precise diagnosis and differential of ICR and TMJOA. We anticipate our assay to be a theoretical foundation on assisting clinicians in better differentiation against the disease definitely.

Free-standing, binder-free and flexible activated carbon/reduced graphene oxide (AC/rGO) composite films with various ratios were fabricated via a facile vacuum-filtration process. It was proved that two-dimensional rGO sheets were an ideal adhesive support for AC. The optimal ratio (AC : rGO = 2 : 1) was determined and the film electrodes displayed a high area specific capacitance of 486 mF cm−2 with a mass of 2.35 mg cm−2 (specific capacitance of 207 F g−1) at 0.2 mA cm−2. The assembled supercapacitor had the advantages of being flexible, lightweight, cheap and environmentally friendly, and can achieve a superior energy density of 16.2 μW h cm−2 at a power density of 100 μW cm−2 and 85% capacitance retention after 10 000 charging/discharging cycles. Moreover, 90% of the capacitance was retained after 1000 bending cycles and there was almost no performance change under different bending angles. These results well demonstrated a great potential for application of AC/rGO film electrodes in wearable and portable electronics.

Graphene material has a large theoretical specific surface area, excellent theoretical conductivity and mechanical flexibility, and is a promising electrode material for supercapacitors. However, two-dimensional graphene sheets are easy to stack, which affects its electrical properties. Specifically, a sponge-like composite hydrogel for high-performance supercapacitors was prepared by one-step hydrothermal method from activated carbon and graphene oxide. Benefiting from the introduced nitrogen-containing groups and the greatly increased specific surface area, the GAC-2 nitrogen-doped activated carbon/graphene hydrogel electrode showed high specific capacitance of 505.6 F g−1. In addition, the composite hydrogel presented an excellent 3D network structure with abundant internal structural pores, in which graphene and activated carbon were cross-linked by strong covalent bonds. This unique structure greatly improves the mechanical flexibility of the composite electrode (the capacitance retention rate is approximately 87.7% after 500 bending tests). And the self-assembled flexible supercapacitor shows an energy density of 26.9 Wh kg−1 at 242 W kg−1 and outstanding capacitance retention rate of about 92.1% after 5000 charge-discharge cycles, confirming its potential application in supercapacitors.

This study intends to develop a standardized instrument for measuring classroom teaching and learning in secondary chemistry lessons. Based on previous studies and interviews with expert teachers, the progression of five quality levels was constructed hypothetically to represent the quality of chemistry lessons in Chinese secondary schools. The measurement instrument was revised from the Evaluation Scale of Effectiveness of Primitive System of Classroom Teaching (ESEPrSCT). 90 videotaped chemistry lessons were collected and measured to validate the instrument in the pilot and field stage. By means of Rasch modeling, the instrument consisting of 18 items with five response categories was finally validated in this study. The results provide the validity and reliability evidence for using this measurement instrument to assess the quality of chemistry lessons.

In this work, the Pd@ Cd(2-methylimidazole)2 (Pd@CdIF-8) was synthesized by two facile methods, in which the original cubic Pd nanoparticles anchored on the surface/interface of CdIF-8 and supported on the acidified activated carbon (AAC). Interestingly, CdIF-8 exhibited sphericity under hydrothermal condition and presented hexahedron under mild liquid. A(B)-PdxCdyIF-8@AAC hybrids are researched by FESEM, TEM, contact angle measurement, XPS, XRD and BET analytical techniques. A(B)-PdxCdyIF-8@AAC hybrids are employed as nonenzymatic sensors for electrochemical detection of H2O2, and both exhibited excellent electrocatalytic activity, especially for A(B)–Pd0.2Cd1.5IF-8@AAC/GCE sensors. A(B)–Pd0.2Cd1.5IF-8@AAC/GCE sensors demonstrated a linear response to H2O2 in the range of from 10 μM to 10.2 mM and 2 μM to 17.5 mM, the sensitivity of 0.195 μAμM−1 and 0.266 μAμM−1, respectively. In addition, asymmetric supercapacitors have been fabricated using A(B)-PdxCdyIF-8@AAC hybrids as positive electrode and exhibited exceptional electrochemical properties with high specific capacitance (452 F g−1 at 0.05 A g−1 and 372 F g−1 at 1 A g−1 of A-Pd0.2Cd1.5IF-8@AAC, and 502 F g−1 at 0.05 A g−1 and 395 F g−1 at 1 A g−1 of B–Pd0.2Cd1.5IF-8@AAC), excellent stability (83.579% maintenance of specific capacitance at 5 A g−1 of A-Pd0.2Cd1.5IF-8@AAC and 78.313% maintenance of B–Pd0.2Cd1.5IF-8@AAC), respectively. Keywords: Acidified activated carbon, A(B)-PdxCdyIF-8@AAC, Electrochemical sensor, Asymmetric supercapacitor

High theoretical capacitance of MnO2 nanoparticles were successfully electrodeposited on the conductive graphene/activated carbon (GN/AC) composite film, and the urchin type MnO2 microspheres were controlled by adjusting the electro-deposition reaction times. The GN/AC/MnO2-1200s composite electrodes exhibited a maximum specific capacitance of 1231 mF/cm2 (MnO2 loading mass of 7.65 mg/cm2 and the mass specific capacitance of 123 F/g) at a current density of 0.5 mA/cm2. The assembled flexible solid-state symmetric supercapacitor had a good mechanical flexibility (about 88.6% of its original capacitance after 500 bending times) and prominent cycling stability (about 82.8% retention in capacitance over 10000 cycles). More importantly, the device could possess a maximum energy density of 0.27 mW h/cm3 and a maximum power density of 0.02 W/cm3. These results well demonstrate a great potential for applications of GN/AC/MnO2 composite electrodes in flexible energy storage devices.