Prussian-blue-analogue derived FeNi2S4/NiS nanoframes supported by N-doped graphene for highly efficient methanol oxidation electrocatalysis.

The design of effective and robust non-noble metal electrocatalysts to enhance catalytic reaction kinetic is critical to promote methanol oxidation catalysis. Herein, hierarchical Prussian blue analogue (PBA)-derived sulfide heterostructures supported by N-doped graphene (FeNi2S4/NiS-NG) as efficient catalysts have been developed for methanol oxidation reaction (MOR). Benefiting from the merits of hollow nanoframes structure and heterogeneous sulfide synergy, FeNi2S4/NiS-NG composite not only possesses abundant active sites to boost the catalytic properties but also alleviates the CO poisoning effect during the process exhibiting favorable kinetic behavior toward MOR. Specifically, the remarkable catalytic activity (97.6 mA cm-2/1544.3 mA mg-1) of FeNi2S4/NiS-NG for methanol oxidation was achieved, superior to most reported non-noble electrocatalysts. Additionally, the catalyst showed competitive electrocatalytic stability, with a current density of over 90% after 2000 consecutive CV cycles. This study offers promising insights into the rational modulation of the morphology and components of precious-metal-free catalysts for fuel cell applications.

Interface engineering of Ni/NiO heterostructures with abundant catalytic active sites for enhanced methanol oxidation electrocatalysis.

Designing efficient and stable non-noble metal electrocatalysts with good performance in reaction kinetics is desirable yet challenging for the study of methanol oxidation reaction (MOR). Herein, we have reported well-defined nanoscale nickel/nickel oxide (Ni/NiO) heterostructures supported by a three-dimensional (3D) porous graphene network (RG) via a delicate interface engineering technique. The as-prepared 3D Ni/NiO/RG composites achieve outstanding catalytic activity (79.5 mA cm-2/1262.1 mA mg-1) for MOR in alkaline solution, outperforming most reported non-precious catalysts. A combined experimental and computational investigation shows that such a good performance benefits from the specific Ni/NiO interface, which not only bears abundant accessible active sites but also improves the energetics of MOR. Moreover, this interface contributes to favorable kinetic and improved structural stability during electrocatalysis, ensuring superior catalytic performance after 1000 consecutive cyclic voltammetry tests for MOR. Our work demonstrates the potential of interface engineering in the rational design of efficient precious-metal-free electrocatalysts.

Polysaccharide hydrogel electrolytes with robust interfacial contact to electrodes for quasi-solid state flexible aqueous zinc ion batteries with efficient suppressing of dendrite growth.

Flexible aqueous zinc-ion batteries (AZIBs) require high conductive and adhesive hydrogel electrolytes. However, high adhesion tends to hinder ion conduction rate. Herein, we designed a water/glycerol binary solvent coordinating the hydrophilic polymers to reconstruct the water molecules' environment in the hydrogel. As a consequence, the interface adhesion strength between Zn and the hydrogel reached 3.0 kPa and the ionic conductivity was up to 16.8 mS cm-1. In addition, inspired by the slurry electrode preparation method, we developed a simple blade coating technique using a non-Newtonian polysaccharide liquid solution to construct an ultra-thin hydrogel electrolyte in situ on the cathode. The thickness of the obtained hydrogel reached 70 µm, and the ultrathin flexible AZIBs were easily constructed by pasting a Zn anode directly on the adhesive hydrogel, showing the potential of flexible AZIBs scalable assembly. In addition, the Zn//Zn symmetrical cells with the hydrogel electrolyte provided stable cycling performance for over 400 h at 0.1 mA cm-2 with suppressed dendrite growth. The assembled Zn//Polyaniline battery and Zn//V2O5 battery also exhibited excellent capacity retention after cycles. This work has realized the hydrogel electrolyte with high adhesion and conductivity, which has good adaptability to metal electrodes and opened up a new practical way for large-scale assembly of flexible energy storage devices.

Silanized Graphene Oxide-Supported Pd Nanoparticles and Silicone Rubber for Enhanced Hydrogen Elimination.

Hydrogen is a dangerous gas because it reacts very easily with oxygen to explode, and the accumulation of hydrogen in confined spaces is a safety hazard. Composites consisting of polymers and catalysts are a common getter, where the commonly used catalyst is usually commercial Pd/C. However, it often shows poor compatibility with polymers, making it difficult to form a homogeneous and stable composite. In this work, palladium chloride (PdCl2) was converted to palladium (Pd) nanoparticles by reduction reaction and supported on graphene oxide (GO) modified by silanization. Spherical Pd nanoparticles with a size of 2-36 nm were uniformly distributed over the Silanized graphene oxide (SGO) matrix. When mixed with Pd/SGO, polymethylvinylsiloxane can be cured to silicone rubber (SR) by B2O3. Afterwards, the vinyl in the polymer can interact with hydrogen under the catalysis of Pd through the addition reaction, thus achieving the purpose of hydrogen elimination. The polymer elastomers with excellent self-healing properties and improved hydrogen elimination performance were prepared and were superior to the commercial Pd/C. In addition, excellent environmental adaptability was also demonstrated. The new getter SR-Pd/SGO provides a new avenue for developing polymer getters with superior properties.

Polypeptide Radical Cathode for Aqueous Zn-Ion Battery with Two-Electron Storage and Faster Charging Rate.

The rapidly growing demand for batteries has led to a lack of global mineral resources and rechargeable organic batteries are paid extensive attention, owing to the abundance resources, light weight, and high flexibility of organic electrodes. However, most organic electrodes that use aliphatic backbones are nondegradable, leading to unsustainability when active sites fail. In this study, a poly(aspartic acid) polypeptide (PASP) with amide links in the backbone and nitroxide radical pendant groups in the side chains is synthesized by modifying the polypeptides with 4-amino-2,2,6,6-tetramethylpiperidine. In combination with a Zn anode, the PASP-TEMPO composite electrode exhibits rapid charge-discharge and superior cycling stability with reversible two-electron redox reaction in aqueous electrolyte. The Zn/PASP-TEMPO organic radical battery delivers a discharge capacity of around 80 mAh g-1 by two-electron reaction and charge-discharge rates of up to 18 A g-1 . Because the redox reaction process of the nitroxyl radical turning into oxoammonium follows a p-type mechanism that interacts with an anion, three electrolytes with different anions are tested in the Zn/PASP-TEMPO organic radical battery. Experimental results indicate that discharge plateau voltage is tunable by choosing different zinc salts as electrolytes. Capacity retention of up to 97.4 % after 500 cycles is realized in 1 m ZnClO4 electrolyte, which can be attributed to the adjacent reaction potentials of the two-step one-electron reaction.

How increased job demand affects nurses' task mastery and deviance in the pandemic era.

AIM: Although normative and ethical procedures are extremely critical for health care providers, during this unique time, when the pandemic suddenly increased job requirements and workloads, maintaining a morally appropriate working style became an increasingly difficult challenge for nurses. Few previous studies have examined whether these highly increased job demands influence nurses' resource condition, in turn affecting their deviance and task mastery. DESIGNS: In the current study, we proposed a theoretical model examining whether nurses' job demands (the predictor) will affect task mastery and deviance (the outcomes) by increasing resource depletion. METHODS: A multiwave field study of 172 nurses from two comprehensive hospitals was conducted to test the proposed theoretical model from April to August 2020. Descriptive statistics, confirmatory factor analyses, correlation coefficients and linear regressions were used to test the hypotheses. RESULTS: The results suggested that even though job demands may temporarily increase nurses' task mastery and decrease their organizational deviance, they ultimately have a negative influence since resource depletion acts as a side effect that suppresses the two direct effects. CONCLUSION: The theoretical contributions and practical implications of our findings were discussed. Specifically, we suggested that healthcare institutions should provide abundant support for nurses to supplement their resource reserves to avoid the risk of potential medical malpractice. IMPACT: Practically, this study tried to emphasize the important role of nurses' resource condition. Especially we aimed to remind managers and leaders cannot just improve nurses' job demand to deal with the public health crises. They also need to focus on their resource condition during pandemics.

Effect of ethical nurse leaders on subordinates during pandemics.

BACKGROUND: As caring in times of pandemics becomes extremely stressful, the volume and intensity of nursing work witness significant increase. Ethical practices are therefore even more important for nurses and nurse leaders during this special period. RESEARCH AIM: The aim was to explore the relationship between ethical nurse leaders and nurses' task mastery and ostracism, and to examine the mediating role of relational identification in this relationship during pandemics. RESEARCH DESIGN: Based on social exchange theory, this study tests a theoretical model proposing that ethical nurse leaders can increase nurses' task mastery and reduce their ostracism by improving their relational identification with leaders during pandemics. PARTICIPANTS AND RESEARCH CONTEXT: A multilevel and multi-wave field study using data from 172 nurses from 45 departments of two comprehensive hospitals was performed from April to August 2020 to test proposed hypotheses. ETHICAL CONSIDERATIONS: We received formal approvals from the ethical committee of the hospital where we conducted this study before the data collection. RESULTS: Ethical nurse leaders can indeed increase nurses' task mastery and reduce their ostracism during the pandemic period; furthermore, nurses' identification with their leaders mediates these relationships. We find that ethical leadership plays an even more important role in improving nurses' task mastery and reducing their ostracism that may be facilitated by pandemics this special time. Nurses will become more identified with their leaders when they are treated by ethical ways. DISCUSSION: The study tries to advance our understanding of the important role of ethical leadership in nurse management literature and provide useful suggestions for healthcare institutions, nurse leaders, and nurses during pandemics. CONCLUSION: Theoretical contributions and practical implications of our findings are discussed. Specifically, we suggest that healthcare institutions cultivate ethical nurse leaders to facilitate nurses' relational identification, which in turn will positively influence work outcomes.

Efficient preparation of high-quality graphene via anodic and cathodic simultaneous electrochemical exfoliation under the assistance of microwave.

Currently, the electrochemical exfoliation of graphene stands out as an efficient, scalable approach to access high-quality products, due to its simplicity, low cost, and environmental friendliness. Here we have proposed an electrochemical method for preparing graphene at both the anode and cathode simultaneously. Graphite was first subjected to ion intercalation sufficiently on the anode and cathode and then expanded ultrafast under the assistance of microwave irradiation. With plenty of ion intercalation and proper microwave irradiation, graphene would be successfully exfoliated. The as-prepared graphene flakes from anode and cathode behave few-layer feature (more than 80% ≤ 4 layers) and large sizes (about 94% are larger than 1 µm), possess low oxygen content and little defects (6.1% and 1.9% oxygen for anodic and cathodic graphene, respectively). In addition, the high yields in our method (the maximum yields for anode and cathode were 81% and 76%, respectively) and the recycling of electrolytes suggest that our method owns great potential for large-scale production and provide an important reference for the commercial preparation of green and low-cost graphene.

Natural developing process of immunoglobulin G4-related sialadenitis after submandibular gland excision: a retrospective cohort study.

OBJECTIVE: This study aimed to evaluate the long-term outcome and quality of life of IgG4-related sialadenitis (IgG4-RS) patients after submandibular gland (SMG) excision without immunomediate therapy. MATERIALS AND METHODS: This retrospective review included patients with IgG4-RS who did not undergo further treatment following SMG excision. All patients diagnosed with IgG4-RS between January 1955 and December 2012 at the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology, were enrolled. The main outcome measures included postoperative IgG4-RS progression rate and differences between patients with and without recurrent disease. The degree of subjective oral dryness was evaluated using the summated xerostomia inventory (SXI); the objective secretory function was assessed by whole saliva flow rate measurements. Serological findings were analyzed during the follow-up. RESULTS: SMG excision was adopted in all of the 83 patients. The median follow-up period was 108 (range 7-396) months. Clinical progression was observed in 54.2% of cases. Patients with other organ involvement (OOI) indicated higher progression rate to a significant extent (P = 0.015, HR = 2.108). The annual progression rate was 20.7% in the group with OOI and was 14.1% in the group without OOI. All cases showed higher levels of serum IgG4; the level was in positive correlation with follow-up time when no therapy was added. 82.4% of cases experienced xerostomia after the surgery, and the degree of dry mouth in patients underwent bilateral resection was significantly more severe than those in unilateral resection. CONCLUSIONS: Surgical excision of involved SMG cannot control the disease progression, which is not recommended for treatment of IgG4-RS. Differential diagnosis is crucial in order to prevent irreversible organ loss and relevant salivary gland dysfunction. Key Points • Surgical excision of involved SMG cannot control progression of IgG4-RS.

A high-voltage quasi-solid-state flexible supercapacitor with a wide operational temperature range based on a low-cost "water-in-salt" hydrogel electrolyte.

Recently, "water-in-salt" electrolytes have provided a huge boost to the realization of high energy density for water-based supercapacitors by broadening the electrochemical stability window. However, the high cost and low conductivity of high concentration LiTFSI greatly restrict the possibility of practical application. Herein, we adopt a new strategy to develop a low-cost and quasi-solid-state polyelectrolyte hydrogel accommodating a superhigh concentration of CH3COOK through in situ polymerization, avoiding the problem that many conventional polymers cannot accommodate ultra-high ion concentration. The polyelectrolyte hydrogel with 24 M CH3COOK exhibits a conductivity of up to 35.8 mS cm-1 and a stretchability of 950%. With advanced N-doped graphene hydrogel electrodes, the assembled supercapacitor yields a voltage window of 2.1 V with an energy density of 33.0 W h kg-1 and superior cyclability with 88.2% capacitance retention at 4 A g-1 after 6000 cycles comparable to those supercapacitors using high-cost LiTFSI salts. Besides, the supercapacitor with excellent temperature stability in the range of -20 to 70 °C can light an LED for more than one minute. The assembled flexible device with the PAAK/CMC-24 M gel film sandwiched in between demonstrates excellent bendability from 0° to 180° and shows great potential for flexible/wearable electronic devices. Our feasible approach provides a new route for assembling quasi-solid-state flexible high-energy storage devices with "water-in-salt" electrolytes.

In Situ Formation of "Dimethyl Sulfoxide/Water-in-Salt"-Based Chitosan Hydrogel Electrolyte for Advanced All-Solid-State Supercapacitors.

Biodegradable hydrogel electrolytes are particularly attractive in the fabrication of all-solid-state supercapacitors due to environmental benignity and avoiding of leakage. The introduction of "water-in-salt" (WIS) electrolytes into hydrogels will further broaden the electrochemical stability window of aqueous supercapacitors significantly. Meanwhile, the addition of an organic co-solvent can effectively overcome the inevitable salt precipitation and extend the temperature adaptability. Herein, an in situ cross-linking approach was demonstrated without any extra binder to obtain a "dimethyl sulfoxide/water-in-salt"-based (DWIS) chitosan hydrogel electrolyte. Interestingly, the addition of 4-7 mol L-1 of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salts not only conforms to the criterion of WIS, but also promoted the successful gelation through the supramolecular complexation between Li+ -solvated complexes and chitosan chains. A hydrogel-based all-solid-state supercapacitor was fabricated using the DWIS chitosan hydrogel as the electrolyte and separator while nitrogen-doped graphene hydrogel (NG) was used as the electrode. The optimized supercapacitor with a wide operating voltage of 2.1 V showed a high specific capacitance of 107.6 F g-1 at 1 A g-1 , remarkable capacitance retention of 80.1 % after 5000 cycles, a superior energy density of 62.9 Wh kg-1 at a power density of 1025.5 W kg-1 , and excellent temperature stability in the range of -20 to 70 °C. These findings suggest that the as-prepared hydrogel electrolyte holds great potential in the practical application of high-performance solid-state energy storage devices.

Ternary PtFeCo alloys on graphene with high electrocatalytic activities for methanol oxidation.

Ternary PtFeCo alloys as alternatives to conventional Pt electrocatalysts are highly important in the field of the methanol oxidation reaction. In this study, we demonstrate a one-pot two-step reduction method for the synthesis of graphene supported PtFeCo alloy nanocomposites as an integrated binder-free catalyst. The synergistic effect of alloying with Fe and Co as well as graphene decorating contributes to an increase in the utilization of the noble metal, namely, reducing the amount of Pt in the nanocomposites to 7%. After tailoring the elemental composition of the alloys, Pt52Fe29Co19@G-7% exhibits a mass activity/specific activity of 1758.2 mA mg-1Pt/3.42 mA cm-2 that is 3.13/3.45 times that of commercial Pt/C in an acidic medium. Impressively, it showed a superior mass current density of 9356.1 mA mg-1Pt at 60 °C which is close to the operating temperature of direct methanol fuel cells. Moreover, the as-obtained Pt52Fe29Co19@G-7% also exhibited excellent CO tolerance and reliable stability compared to commercial Pt/C. The structural characterization further verifies that the surface strain and electronic effect play a critical role in determining the electrocatalytic properties of PtFeCo@G nanocomposites for the methanol oxidation reaction.

CoP/C Nanocubes-Modified Separator Suppressing Polysulfide Dissolution for High-Rate and Stable Lithium-Sulfur Batteries.

A functioned PP was chosen as a separator to suppress the shuttling effect of soluble polysulfide in lithium-sulfur batteries (LSBs). Nanocubic cobalt phosphide/carbon (CoP/C) was modified on PP membrane through a simple vacuum filtration method. This CoP/C-modified PP separator not only efficiently captures polysulfides through strong chemical affinity but also facilitates the conversion of the soluble intermediates due to the fast transfer at the interface. In consequence, the cell with a CoP/C-modified separator exhibits a low-capacity decay of only 0.08% per cycle over 500 cycles at 1 C with an initial capacity of 938 mAh g-1 and a superior rate performance of 594 mAh g-1 at 4 C. Even with a high loading of 3.2 mg cm-2, the cell still exhibits an excellent reversible capacity of 601.3 mAh g-1 after 100 cycles at 0.5 C. This work provides a new strategy to effectively restrict the polysulfide shuttling.

Surface Reconstruction of La0.8Sr0.2Co0.8Fe0.2O3-δ for Superimposed OER Performance.

Perovskites have become important OER electrocatalysts. Herein, as-prepared La0.8Sr0.2Co0.8Fe0.2O3-δ (LSCF-0) is chosen as a sample to exhibit the superimposed effect of surface reconstruction accompanied by reduction of Co3+ to Co2+ on the further improvement of its activity and stability. As-synthesized LSCF-0 perovskite is chemically treated by simply immersing in an aqueous solution of NaBH4 for 1.0 h at room temperature. The optimized LSCF (LSCF-2) owns an amorphous layer consisting of nanosized particles of ∼20 nm (vs smooth bulk crystalline surface for untreated LSCF), which exhibits superior OER performance to LSCF-0. LSCF-2 has an overpotential of 248 mV (10 mA cm-2) and a Tafel slope of 51 mV dec-1 (vs 355 mV and 76 mV dec-1 for LSCF-0 and 381 mV and 91 mV dec-1 for LCO) and an excellent cycle stability for 20 h running. This work supplies a new strategy to enhance OER performance through surface reconstruction of as-prepared perovskites.

[Biocompatibility of porous calcium phosphate ceramic nanocomposite].

OBJECTIVE: To study the biocompatibility of porous calcium phosphate ceramics nanocomposite. METHODS: The biocompatibility was evaluated via experiments including the hemolysis test, hemopexis test, acute systemic toxicity test, pyrogen test, and intramuscular implant test, in which biphasic calcium phosphate nanocomposite (NanoBCP) presented as leaching solution, suspension or blocks of 5 mmx5 mmxl mm. Animals including New Zealand Rabbits, Kunming mice, SD rats were selected as the host. RESULTS: The hemolysis of NanoBCP was 1.1% (<5%). Four coagulation index levels were within the normal range. In pyrogen test, the temperature of each experimental rat increased by 0.35, 0.40, 0.28 degrees C (<0.60 degrees C, in accordance with the pyrogen-free criterion for biomedical materials). No consequent death, dyspnoea, organ dysfunction, severe peritoneal irritation or ptosis was observed in acute systemic toxic test. Newly-formed fibrous tissue could be found after the implantation. CONCLUSION: The material possesses outstanding biocompatibility and degradability with no toxicity or irritation, contains no pyrogen, as well as better degradation properties than biphasic calcium phosphate.

[Relationships between dental calcification stages and cervical vertebral bone ages among children and adolescents in Chengdu].

OBJECTIVE: To investigate the relationship between the stages of calcification of various teeth and cervical vertebral bone ages among children and adolescents in Chengdu. METHODS: The study subjects consist of 256 children and adolescents in Chengdu with age ranging from 10 to 16 years. All panoramic radiographs and cephalometric radiographs were obtained. The relationship with the stages of chronological ages, calcification of various teeth and cervical vertebral bone ages were analyzed. RESULTS: The Spearman rank correlation coefficient revealed highly significant relationships between cervical vertebral bone ages and chronological ages (r = 0.726, P < 0.01). Dental ages and chronological ages had medium relationship (r = 0.629, P < 0.01), also dental ages and cervical vertebral bone ages medium relationship (r = 0.668, P < 0.01). CONCLUSION: Cervical vertebral bone ages, chronological ages and dental calcification stages have correlation among children and adolescents in Chengdu. The cervical vertebral bone ages have high connection with chronological ages. Cervical vertebral bone age might be a better indicator in judging growth and development of children and adolescents during orthodontic treatment.