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Chayote is rich in non-starch polysaccharides. The physicochemical properties of non-starch polysaccharide from chayote were not study extensively. In the present research, non-starch polysaccharide of chayote (CP-CHE) extracted by conventional heating extraction method was obtained, and the preliminary physicochemical and functional properties of CP-CHE had been carried out. The results indicated that the CP-CHE was rich in galactan, glucoses and galacturonic acid. Also, CP-CHE had the negatively charged, a wide distribution of molecular weight and particle size. Additionally, CP-CHE solutions had shear thinned fluid property when the concentrations between 1% to 4%. The results of this study would be beneficial to the application of CP-CHE in food and improve the economic value of chayote.

Recently, organic-inorganic hybrid perovskite solar cells have been considered as the new generation of photovoltaic devices due to their excellent performance. However, their finite interfacial stability limits their further commercialization. How to improve their stability is one of the important issues in current scientific research. Herein, a bilayered titanium dioxide nanorod array-flower (B-TiO

Microbial fabrication is eco-friendly for nobel-metal catalysts typically used in proton exchange membrane fuel cell (PEMFC). In our study, nano-Pd electrocatalysts were successfully prepared by using three Shewanellas as precursors through hydrogen reduction (200 °C) and carbonization (800 °C). The analysis revealed that the catalysts showed outstanding ORR electrocatalytic performance via a predominant four-electron oxygen reduction pathway in alkaline medium. The best performance was obtained for Pd/HNC-32, which showed a mass activity at 0.526 A mg−1, 3.78 times higher than that of commercial Pd/C. Shewanella putrefaciens CN-32 was a more effective Pd-adsorbent. The enhanced performance can be ascribed to the small Pd-particle size and uniform dispersion on microbial support, which results from stronger hydrophilicity of Shewanella putrefaciens CN-32. The content of nitrogen is another key to the performance of Pd/HNC-32. This study developed a promising strategy for screening microbial strains for electrocatalyst fabrication.

Oral lichen planus, a chronic inflammatory immune disease, occurs in the oral mucosa. We aimed to assess the prevalence and possible influencing factors of oral lichen planus in patients with diabetes mellitus.This cross-sectional study involved 525 patients with diabetes mellitus and 525 controls. We collected information on blood glucose level, duration of diabetes, diabetic complications, treatment methods, other systemic diseases and medication history.Oral lichen planus was significantly more prevalent in the diabetes mellitus/type 2 diabetes mellitus group than in the controls (2.3%/2.2% vs. 0.6%, p = 0.019/0.022). There was no significant association between patients with diabetes mellitus with and those without oral lichen planus in age (p = 0.195), sex (p = 0.390), blood glucose level (p = 1), duration of diabetes (p = 0.638), diabetic complications (p = 1), treatment methods (p = 0.962), other systemic diseases (p = 0.891) and medication history (p = 0.848).Diabetes mellitus was associated with oral lichen planus; there was a higher prevalence of oral lichen planus in patients with diabetes mellitus/type 2 diabetes mellitus than in those without diabetes. Oral lichen planus development in patients with diabetes mellitus was not significantly associated with age, sex, blood glucose level, duration of diabetes, diabetic complications, treatment methods, other systemic diseases and medication history.

A flexible carbon nanofiber film with high conductivity was prepared by electrospinning, and then Cu was uniformly deposited on the fiber film by pulse electrodeposition to prepare Cu nanocrystal/carbon nanofiber film. Cu@PtCu/carbon nanofiber (Cu@PtCu/CNF) catalytic films were synthesized by in-situ substitution reduction. The Cu@PtCu/CNF catalytic film solves the problem of uneven activity of the catalytic layer and can be directly used as the catalytic layer. The morphology and structure were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Electrochemical test results show that the Cu@PtCu/CNF catalytic films obtained at the chloroplatinic acid concentration of 0.5 mg·mL

A novel oxygen reduction reaction (ORR) electrocatalyst silver@platinum-cobalt-rGO nanoflower (Ag@PtCo-rGO NFs) is prepared by hydrothermal reduction method. The formation of silver chloride likes elm leaf microstructure in the reaction process, performing as a template. The Ag@PtCo-rGO NFs exhibit excellent electrocatalytic activity, whose specific activity is 9 times higher than that of commercial Pt/C. More importantly, Ag@PtCo-rGO NFs demonstrate excellent durability than JM Pt/C for ORR in acid media, as evidenced by accelerated durability test after 40,000 cycles. These excellent performances can be attributed to the special structure, atomic steps and synergistic effect between Pt, Ag and Co. The density functional theory calculation shows that Ag@PtCo has the best activity, which is related to the transition state for O–O bond. This work proposes a promising pathway for the synthesis of surfactant-free nanoflowers structure catalysts with high catalytic performance and low cost.

For the study, we prepared a low grain boundary three-dimensional CH3NH3PbI3 crystal (3D-MAPbI3) on TiO2 nanoarrays by inhibition of ammonium iodide and discussed the formation mechanism of the crystal. Based on the 3D-MAPbI3 crystal, solar cells showed modified performance with a power conversion efficiency (PCE) of up to 19.3%, which increases by 36.8% in contrast to the counterparts. We studied the internal photocurrent conversion process. The highest external quantum efficiency is up to 92%, and the electron injection efficiency is remarkably facilitated where the injection time decreases by 37.8% compared to the control group. In addition, based on 3D-MAPbI3, solar cells showed excellent air stability, which possesses 78.3% of the initial PCE, even though they were exposed to air for 30 days. Our results demonstrate a promising approach for the fabrication of perovskite solar cells with high efficiency and stability.

In the process of processing, the residual stress in the deformed component will play a crucial role in the assembly and future use. This paper analyzes the deformation behavior of martensite phase transition induced by deformation through unidirectional stretching. The martensite phase variables and residual stress distributions after stretching were measured. The calculation model of residual stress distribution is established considering the phase change factors. It provides a theoretical basis for the calculation of phase transition behavior and residual stress distribution in the complex deformation process. A dynamic model based on stress and strain was established under different conditions, and the realization of martensite transformation was added to the finite element software with the help of secondary development subroutine. By comparing with the test data, the results show that the distribution pattern of residual stress can better reflect the residual stress after deformation under the consideration of the phase transformation of martensite.

Since most Internet of things (IoT) devices are energy-limited, increasingly more manufacturers have chosen to develop IoT applications based on group communication. For these applications, a secure and effective authenticated group secret key is fundamental to whole group communication. A large number of related protocols have been proposed to address this security problem. However, most of them have a centralized architecture, which is vulnerable to a single point of failure. Blockchain technology has the potential to address the challenges mentioned above because of its distributed, secure, and private property. Thus, this paper proposes a blockchain-based authenticated group key agreement protocol for IoT. The proposed protocol introduces a new entity called the device manager, who acts as an intermediary to connect IoT devices with blockchain networks. Security analysis demonstrates the robustness of the proposed protocol to various kinds of attacks. Besides, the simulation results further show that the time costs of protocol operations are reasonable and suitable for IoT environments.

Refractory recurrent aphthous stomatitis (RRAS) manifests as severe ulcerative lesions of the oral mucosa with poor healing and a poor response to conventional therapy, with or without systemic diseases. Its treatment remains a clinical challenge owing to the lack of effective therapies. Recently, biologics have emerged as promising targeted therapies for RRAS. The biologics targeting specific inflammatory pathways involved in the pathogenesis of RRAS, including tumor necrosis factor-alpha inhibitors and interleukin inhibitors, offer a more precise and promising therapeutic approach for RRAS. These targeted therapies have been shown to promote healing and decrease recurrence frequency in, and improve the quality of life of patients with RRAS. Herein, the types and mechanisms of biologics currently used to treat RRAS have been reviewed; furthermore, the dose, duration, therapeutic efficacy, and adverse effects of RRAS with or without certain associated systemic diseases, and the current problems and future directions have been discussed.

Shape-tunable PtAg nanocatalysts including PtAg nanoflowers (NFs) and PtAg nanowires (NWs) are prepared by a facile hydrothermal reduction method, via adjusting the precursor ratio of Pt/Ag and subsequent UV-irradiation. Physicochemical characterizations reveal that the as-prepared catalysts have a porous structure, which forms from the conversion of AgCl to Ag nanoparticles. These features favor both oxygen mass transfer and accessibility of active sites. The as-prepared Pt1Ag4 NWs exhibit superior catalytic performances for ORR. The mass activity of Pt1Ag4 NWs is 11.4 times higher than that of 20% Pt/C. More important, the electrochemically active surface area (ECSA) of Pt1Ag4 NWs is 2.5 times larger than that of commercial Pt/C.

There are many types of cathodic oxygen reduction catalysts for proton exchange membrane fuel cell (PEMFC). Among them, Pt-based catalysts are most likely to be industrialized because of their incomparable high activity. However, most of the Pt-based catalysts have not reached the maximum activity and stability. Herein, porous carbon nanofibers (p-CNF) with self-nitrogen-doped as catalyst supports were successfully prepared by the method of electrospinning. After functionalization, the functionalized porous carbon nanofibers (f-p-CNF) were loaded with PtPd alloy nanoparticles to obtain the catalyst (Pt0.66Pd0.33/f-p-CNF), which has excellent electrochemical performance. Its specific activities (SA) and Pt mass activities (Pt MA) are 1.73 and 1.86 times of the commercial JM 20% Pt/C (JM20), respectively. The results can be attributed to the porous structure of nanofibers, which not only facilitate the transmission of gas-liquid and electron but also increase the exposure of active sites. And the doped nitrogen of fibers may regulate the electronic structure of the metal active substance to increase the activity. This work provides catalyst with novel structure which could enable PEMFCs to be more efficient in operation.

In a modern electronic medical system, data sharing between medical institutions must have a more comprehensive understanding of the patient’s condition. However, different hospitals typically use other databases, even if the data belong to the same person. Each hospital manages its database in a centralized and closed manner. This approach makes the databases vulnerable to single-point attacks by malicious attackers and undermines medical care continuity. In this paper, we use a blockchain concept that provides a secure distributed environment to avoid single-point attacks. We develop a novel medical data sharing schedule that uses the blockchain to integrate each hospital’s resources. Compared with other blockchain-based schemes, we categorize and manage different requests for medical data sharing: (i) sharing between hospitals of the same level; (ii) sharing between hospitals of different levels. Additionally, our schedule ensures the security of individual entities in the process of data sharing. We conduct a security analysis and a comparative validation to show that the proposed systems are secure. In the subsequent analysis of the system, the feasibility of the proposed system was examined.

Objective : To compare the efficacy and safety of topical antifungal drugs for oral candidiasis in adults and children. Study Design : Databases were searched from their inception to December 2020. The inclusion criterion was randomized controlled trials comparing topical antifungal agents. The primary outcomes were clinical response and mycological cure rates. The secondary outcomes were adverse reaction incidence and relapse rate. Results : In adults with oral candidiasis, fluconazole showed a better clinical response rate than clotrimazole (P = 0.001, RR = 1.14), but a similar mycological cure rate (P = 0.57, RR = 1.03). There was no significant difference in clinical response and mycological cure rates with either fluconazole and amphotericin B (clinical: P = 0.47, RR = 0.96; mycological: P = 0.99, RR = 1.00) or itraconazole and clotrimazole (clinical: P = 0.51, RR = 1.06; mycological: P = 0.45, RR = 1.32). For immunocompetent patients, fluconazole was superior to clotrimazole in terms of clinical response rate. For immunosuppressed patients, clotrimazole and itraconazole presented similar clinical response and mycological cure rates, but the relapse rate with itraconazole was lower than that with clotrimazole. In infants, miconazole and nystatin showed similar clinical response rates (P = 0.36, RR = 1.23), whereas miconazole presented a superior mycological cure rate (P = 0.03, RR = 4.03). Conclusions : Fluconazole and amphotericin B are recommended as topical antifungal agents for adults with oral candidiasis. Existing studies tend to recommend fluconazole for immunocompetent patients and itraconazole for immunosuppressed patients, whereas miconazole is recommended for infants.

One-dimensional carbon nanofibers hold great promise to be potential candidates as high-efficiency electrocatalysts for oxygen reduction reaction (ORR). However, the catalysts in powder form always aggregate when preparing catalyst layer, which significantly hinders the extensive application. Herein, we report the facile synthesis of iron and nitrogen co-containing porous carbon nanofibers derived from PAN nanofibers existing as a flexible film via the electrospinning method, which could avoid aggregation when fabricating catalyst layer of fuel cells. The Fe–N/N–C NFs exhibit onset potential of 0.95 V and the half-wave potential of 0.78 V in 0.1 M KOH solution, suggesting superior electro-catalytic activity for ORR. Meantime, for Fe–N/N–C NFs catalyst, it shows a nearly four electron transferring process and the current density only decreases by 14.2% after 40,000 s. This easy and facile method provides a new idea for synthesis of oxygen reduction reaction with high-activity and good-stability.

While noble metals loaded on carbon-based supports are commonly used as oxygen reduction catalysts for fuel cell cathodes, the preparation process is complicated and expensive cost. In this paper, Pd2+ was first adsorbed on Shewanella by its adsorption characteristics, then the Pd supported on Shewanella catalyst was obtained after carbonization at 600 °C and hydrogen reduction at 200 °C. The Shewanella cells retain the rod shape of bacteria following pyrolysis under high temperatures, while N and Pd heteroatoms are uniform distribution on the carbon matrix. As a result, Pd supported on Shewanella catalyst exhibits excellent electrocatalytic activity for ORR via a dominant four-electron oxygen reduction pathway in alkaline medium. More importantly, the mass activity of the prepared catalyst was 5.8 times higher than that of commercial Pd/C, and its stability was also better than the Pd/C, which could be promising alternatives to costly Pt-based electrocatalysts for ORR.

A novel platinum-palladium/carbon nanowires (PtPd/CNWs) catalysts are successfully prepared by electrospinning for the oxygen reduction reaction (ORR). The prepared PtPd/CNWs catalysts exist in the form of membrane, which can be directly applied as catalyst layer in membrane electrode assembly. The ORR activity of binary PtPd/CNWs catalysts are enhanced significantly in comparison to the ternary platinum-palladium-gold/carbon nanowires (PtPdAu/CNWs) catalysts and 20% Pt/C. Here, the gold in PtPdAu/CNWs mainly exists in larger gold nanoparticles rather than in the form of ternary alloy with Pt, Pd. The mass activity and special activity of PtPd/CNWs are 4.230 times and 4.225 times than that of 20% Pt/C, respectively. Moreover, the electrochemical active surface areas (ECSAs) of PtPd/CNWs catalysts almost keep constant after 5000 potential cycling, whereas 20% Pt/C drops almost 40% after 5000 potential cycling.

Objective To examine the comparative efficacy and safety of topical administration for oral lichen planus. Materials and methods An electronic database search (1st January 1946 to 1st May 2020) for randomised controlled trials identified 34 studies involving eight interventions (clobetasol, betamethasone, triamcinolone, dexamethasone, fluocinolone, tacrolimus, pimecrolimus, and cyclosporine); these studies were subjected to network meta-analysis using direct and indirect comparisons [efficacy indicators: clinical response rate, symptom-reducing effect (visual analogue scale score), sign-reducing effect (Thongprasom-scale score) and relapse; safety indicator: adverse event occurrence]. Results Compared with placebo, tacrolimus had the best clinical response rate (odds ratio (OR), 57.78 [95% CI 3.15-1060.52]; P-score, 0.8654) and cyclosporine had the worst (OR, 3.61[95% CI 0.20-66.62]; P-score, 0.2236); tacrolimus had the best symptom-reducing effect (standardised mean difference (SMD), 1.06 [95% CI 0.41-1.71]; P-score, 0.9323) and fluocinolone had the worst (SMD, -0.54 [95% CI -1.44-0.36]; P-score, 0.0157); dexamethasone had the best sign-reducing effect (SMD, 3.60 [95% CI 1.74-5.45]; P-score, 0.8306) and clobetasol had the worst (SMD, 2.63 [95% CI 1.66-3.61]; P-score, 0.2581); and pimecrolimus performed best (OR, 0.04 [95% CI 0.00-0.64]; P-score, 0.9227) and clobetasol performed the worst [OR, 0.60; 95% CI 0.15-2.45; P-score, 0.2545] in reducing relapse. Regarding safety, dexamethasone was the safest compared with placebo [OR, 0.37; 95% CI 0.05-2.57; P-score, 0.9337), whereas fluocinolone ranked low for safety [OR, 9.48; 95% CI 1.50- 60.03; P-score, 0.1189]. Conclusions The relative ranking of topical administration varies according to the different indicators. Based on the joint consideration of clinical response rate and adverse event occurrence, dexamethasone, triamcinolone and betamethasone are recommended for better efficacy and safety. The optimal treatment for oral lichen patients varies under different conditions.

Here we report a dramatically enhanced hydrogen evolution reaction (HER) catalyst by acid etched MoS2 (A-MoS2). For the etching and oxidation effects of HNO3, the active site and electrical transport are significantly improved by simply controlling of processing time. The A-MoS2 exhibits promising electrocatalytic performance, including much smaller onset overpotential (∼80 mV), an overpotential of 210 mV at 10 mA/cm2, and a Tafel slope of 97 mV/dec (the pristine MoS2 180 mV/dec). The enhanced HER performance of MoS2 may be attributed to the increased edge S atoms and the charge induced by the O doping.

To enhance the activity and durability of platinum (Pt) or platinum-based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), fabrication of low-cost platinum catalysts with durable structure is necessary. Here, a series of one-dimensional (1D) platinum-gold/titanium dioxide nanowires (PtAu/TiO2 NWs) catalysts with different Pt/Au/Ti ratios were synthesized by electrospinning, and the microstructure as well as its electrochemical properties for ORR were investigated. The results illustrate that PtAu/TiO2 NWs indicate a parabolic-type ORR performance as a function of compositions. The optimized Pt1Au1/(TiO2)1 NWs exhibited 4.19 times in mass activity and 2.82 times in SA when compared with commercial Pt on carbon catalyst (20% Pt/C). In addition, the stability test shows that the ECSA of Pt1Au1/(TiO2)1 NWs present almost 20% decrease, while the 20%Pt/C drops more than 40% at the same condition. The extraordinary activity of Pt1Au1/(TiO2)1 NWs could be attributed to the synergistic effect of TiO2 and the durability attributed to Au and C skin. The nanowires with larger specific area show that the Pt electronic structure can be changed by the neighbouring TiO2, further decreasing the d-band gap to enhance catalytic activity.

As catalytic active sites of nitrogen (N)-doped carbon nanomaterials (CNMs) for oxygen reduction reaction (ORR) are always under debate, synthesis of high purity pyridinic-N dominated CNMs is an effective approach to study the relation between pyridinic-N and active sites, as well as catalytic mechanism for ORR. Herein, the carbon nanofibers (CNFs) etched by hydrofluoric (HF) acid can be used to synthesize pure pyridinic-N, suggesting that the exposed edge-patterned surface facilitates to synthesize pure pyridinic-N. Moreover, it reveals that the carbon atoms adjacent to pyridinic-N could be the catalytic active sites for ORR.

The Fe-N-C nanofibers (NFs) exhibit excellent electro-catalytic activity for oxygen reduction reaction (ORR), which is essential for energy conversion system. Compared with the traditional ink-based electrode, we synthesized the structured Fe-N-C ANFs/CP (activated NFs derived from polypyrrole(PPy) doped with iron atoms in situ grown on carbon paper) by electrochemical polymerization. Herein, we investigate the effect of the iron concentration on the electro-catalytic activity for ORR, revealing that the as-prepared 0.05-Fe-N-C ANFs exhibit superior electro-catalytic activity than 0.01-Fe-N-C ANFs, 0.03-Fe-N-C ANFs as well as 0.10-Fe-N-C ANFs and excellent durability in alkaline solution. It is shown that the better electro-catalytic activity of 0.05-Fe-N-C ANFs for ORR could be ascribing to the fluffy fibrous structure, higher Fe-N x concentration, and well-dispersed catalytic active sites.

The controllable synthesis of single nitrogen (N) type doped carbon nanomaterials (CNMs) is of significant importance to evaluate the effects of different N types on electro-catalytic activity for oxygen reduction reaction (ORR) in experiment. Herein, the chaotic edge planes of the as-synthesized platelet carbon nanofibers (plCNFs) are tailored by acid etching of HF to obtain abundant exposed active edge sites while maintaining the interior graphene patterns intact. The N bonding configuration belonging to pyridinic type is nearly 100% and the concentration of the pyridinic-N in the tailored plCNFs reaches up to 12.61 at.%. Electrochemical tests show that N-plCNFs (HF) exhibits improved ORR activities compared with N-plCNFs and the carbon atoms adjacent to pyridinic-N could be the catalytic active sites for ORR. In addition, the generation mechanism of pyridinic-N in tailored plCNFs is briefly elaborated.