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1.
Opt Express ; 31(20): 32909-32924, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37859083

RESUMO

Serial femtosecond crystallography at X-ray free electron laser facilities opens a new era for the determination of crystal structure. However, the data processing of those experiments is facing unprecedented challenge, because the total number of diffraction patterns needed to determinate a high-resolution structure is huge. Machine learning methods are very likely to play important roles in dealing with such a large volume of data. Convolutional neural networks have made a great success in the field of pattern classification, however, training of the networks need very large datasets with labels. This heavy dependence on labeled datasets will seriously restrict the application of networks, because it is very costly to annotate a large number of diffraction patterns. In this article we present our job on the classification of diffraction pattern by weakly supervised algorithms, with the aim of reducing as much as possible the size of the labeled dataset required for training. Our result shows that weakly supervised methods can significantly reduce the need for the number of labeled patterns while achieving comparable accuracy to fully supervised methods.

2.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 31(4): 954-959, 2023.
Artigo em Chinês | MEDLINE | ID: mdl-37551461

RESUMO

OBJECTIVE: To investigate the cytogenetic characteristics and prognostic risk factors for elderly patients with newly diagnosed elderly acute myeloid leukemia(AML). METHODS: Cytogenetic test results of 76 elderly patients with AML admitted to the First Affiliated Hospital of the University of Science and Technology of China (Anhui Provincial Hospital) from April 2015 to December 2021 were retrospectively analyzed, and analyzed clinical characteristics of patients and risk factors influencing prognosis. RESULTS: According to cytogenetic risk stratification, 76 newly treated elderly AML patients were divided into the favorable, intermediate, and unfavorable groups with 6(7.9%), 58(76.3%), and 12(15.8%) cases, respectively. There was no significant difference in the patient's clinical characteristics and prognosis with the cytogenetics-risk classification groups. Correlation analysis showed that patients' objective response rate (ORR) was related to the age of onset and the mutation status of the CEBPA gene. Logistic regression analysis found that age ≥70 years was an independent risk factor for patients' ORR (OR=0.110, P=0.005). Remission determined the 1-year OS rate (OR=0.049, P=0.005). CONCLUSION: There is no significant difference in clinical characteristics among aged AML patients treated at initial treatment in different cytogenetic risk groups. The age of onset ≥70 years is the determinant of whether patients can obtain ORR, and the rate of ORR is closely related to the 1-year OS rate.

3.
Small Methods ; : e2300414, 2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37365950

RESUMO

Flexible intelligent actuators with the characteristics of flexibility, safety and scalability, are highly promising in industrial production, biomedical fields, environmental monitoring, and soft robots. Nanocomposite hydrogels are attractive candidates for soft actuators due to their high pliability, intelligent responsiveness, and capability to execute large-scale rapid reversible deformations under external stimuli. Here, the recent advances of nanocomposite hydrogels as soft actuators are reviewed and focus is on the construction of elaborate and programmable structures by the assembly of nano-objects in the hydrogel matrix. With the help of inducing the gradient or oriented distributions of the nanounits during the gelation process by the external forces or molecular interactions, nanocomposite hydrogels with ordered structures are achieved, which can perform bending, spiraling, patterned deformations, and biomimetic complex shape changes. Given great advantages of these intricate yet programmable shape-morphing, nanocomposite hydrogel actuators have presented high potentials in the fields of moving robots, energy collectors, and biomedicines. In the end, the challenges and future perspectives of this emerging field of nanocomposite hydrogel actuators are proposed.

4.
Huan Jing Ke Xue ; 44(5): 2746-2755, 2023 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-37177947

RESUMO

Exploring the biogeochemical cycle characteristics of soil carbon, nitrogen, and phosphorus in farmland in the dryland of the loess plateau can provide scientific basis and technical support for efficient crop production and sustainable land use. Here, based on a long-term (24 year) straw return field experiment in Shouyang, Shanxi province, the effects of different straw return regimes, i.e., straw mulching (SM), direct straw return (DS), animal-digested straw return (AS), and non-straw return (CK), on the stoichiometric ratio of soil elements and extracellular enzyme activities were studied. The vector angle and length were calculated to indicate the resource constraints faced by microorganisms. The vector angle was greater than 45° and less than 45°, indicating that microorganisms were limited by phosphorus and nitrogen, respectively. The greater the deviation from 45°, the greater the degree of limitation, and the longer the vector length, the more severely limited by carbon. The results showed that ① the soil C/N and C/P of long-term straw returning ranged from 9.81 to 14.28 and from 14.58 to 21.92, with the mean values of 12.36 and 17.51, respectively, which were 6.0% and 4.2% lower than that at the initial stage of the experiment. The soil N/P was distributed between 1.27 and 1.57, with an average of 1.42, which was 2.2% higher than that in the initial stage. The soil C/N and C/P ratios showed a trend of first decreasing and then increasing, the soil N/P ratio basically showed a flat trend, and there was no significant difference in soil element metering ratios between different straw returning treatments. ② Compared with the 24-year long-term non-straw return treatment, the activities of ß-1,4-glucosidase (BG) and ß-1,4-N-acetylglucosaminidase (NAG) in the soil of the long-term straw mulching treatment increased by 134.4% and 107.5% (P<0.05), the activities of BG and alkaline phosphatase (AP) in the soil of the long-term straw mulching treatment decreased by 59.3% and 59.5% (P<0.05), respectively, and the activities of NAG in the soil of the long-term straw mulching treatment increased by 102.8% (P<0.05). Under the long-term straw returning treatment, soil microorganisms were faced with carbon and phosphorus limitation as a whole. Long-term straw mulching aggravated microbial carbon limitation, and animal-digested straw return could alleviate the degree of carbon limitation. Compared with that in the 24-year long-term non-straw return treatment, soil EEAC/N could be significantly reduced by the animal-digested straw return treatment, and soil EEAC/P could be increased by the direct straw return treatment. The three straw returning methods had no significant indigenous effect on soil EEAN/P. The overall vector angle was greater than 45°, and the vector length increased by 3.8%-20.1% compared with that in the initial stage. ③ Correlation analysis showed that C and N inputs were significantly negatively correlated with BG activity; available nitrogen was significantly correlated with NAG activity, AP activity, and EEAC/N; C/P was significantly positively correlated with EEAC/N; there were significant correlations between N/P and NAG activity, AP activity, EEAC/N, and EEAC/P; and there was no significant correlation between EEAN/P and any environmental factors. In conclusion, the availability of soil nitrogen and phosphorus elements and N/P ratio had significant effects on soil extracellular enzyme activity and stoichiometric characteristics under different long-term straw returning treatments. In the future, more attention should be paid to the improvement of organic carbon and the promotion of nitrogen and phosphorus availability in farmland soil in soil-efficient cultivation and agricultural production activities.


Assuntos
Carbono , Solo , Solo/química , Carbono/análise , Fósforo/análise , Nitrogênio/análise , Fertilizantes/análise , Agricultura/métodos , China , Microbiologia do Solo
5.
Nano Lett ; 22(20): 8101-8108, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36190438

RESUMO

Direct and rapid printing and surface patterning of hydrogel thin films are of great significance in the construction of advanced electronic devices, yet they are greatly underdeveloped due to the intrinsic contradiction between mechanical strength and self-healability as well as recyclability. Here, we present a universal and rapid slipping-directed route with a newly developed water-soluble star polymer hydrogel for direct and reproducible printing and patterning of freestanding functional thin films with precisely controlled thicknesses, components, and surface structures on a large scale. The resulting thin films combine the features of large transmittance (93%), tough mechanical strength (114 MPa), multiresponsive self-healability, recyclability, and remarkable multifunctionality. With the unique humidity-sensitive properties as motivation, diverse humidity-sensing devices including an actuating switch, a supercapacitive sensor, and a noncontact electronic skin are facilely constructed through the humidity-induced transverse, longitudinal, and patterning assembly techniques, respectively. The method presented here is universal and efficient in the fabrication and assembly of thin films with controlled configuration and functionality for advanced flexible electronics.


Assuntos
Hidrogéis , Dispositivos Eletrônicos Vestíveis , Hidrogéis/química , Polímeros/química , Impressão Tridimensional , Água
6.
ACS Nano ; 16(8): 12095-12106, 2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35912958

RESUMO

Engineering multifunctional superstructure cathodes to conquer the critical issue of sluggish kinetics and large volume changes associated with divalent Zn-ion intercalation reactions is highly desirable for boosting practical Zn-ion battery applications. Herein, it is demonstrated that a MoS2/C19H42N+ (CTAB) superstructure can be rationally designed as a stable and high-rate cathode. Incorporation of soft organic CTAB into a rigid MoS2 host forming the superlattice structure not only effectively initiates and smooths Zn2+ transport paths by significantly expanding the MoS2 interlayer spacing (1.0 nm) but also endows structural stability to accommodate Zn2+ storage with expansion along the MoS2 in-plane, while synchronous shrinkage along the superlattice interlayer achieves volume self-regulation of the whole cathode, as evidenced by in situ synchrotron X-ray diffraction and substantial ex situ characterizations. Consequently, the optimized superlattice cathode delivers high-rate performance, long-term cycling stability (∼92.8% capacity retention at 10 A g-1 after 2100 cycles), and favorable flexibility in a pouch cell. Moreover, a decent areal capacity (0.87 mAh cm-2) is achieved even after a 10-fold increase of loading mass (∼11.5 mg cm-2), which is of great significance for practical applications. This work highlights the design of multifunctional superlattice electrodes for high-performance aqueous batteries.

7.
Angew Chem Int Ed Engl ; 61(42): e202209687, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36039479

RESUMO

Soft matter catalyst system allowing controllable manipulation of the organized nanostructure and surface property holds the potential for renewable energy. Here we demonstrate the construction of a continuously regenerative hydrogel photocatalyst that confines the metal-thiolate coordination induced nanocavity into robust micro-sized spongy network for water splitting. Thanks to low vaporization enthalpy and fast proton mobility of water molecules confining in nanocavities, the composite delivers outstanding photocatalytic H2 production (TOF of 4568 H2 h-1 ), nearly 4.5 times higher than that on the catalyst without confinements. Incorporating with conductive polymers, the TOF is substantially improved to 7819 H2 h-1 . Impressively, continuous regeneration is for the first time achieved with H2 production retention improved from 24 % to 72 % by regulating optically-active catalyst surfaces. This optical regeneration method provides new avenues for sustainable solar energy conversion.

8.
Nano Lett ; 22(15): 6444-6453, 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-35748657

RESUMO

Realizing autonomous self-healing and high stretchability of flexible supercapacitors over a wide temperature range remains a big challenge because of simultaneous incorporation of self-healing, stretchable and temperature-tolerant elements into a device as well as unfavorable electrochemical kinetics in harsh conditions. Here, we demonstrate for the first time an autonomous self-healing and intrinsically stretchable supercapacitor that can work at all-climate environments assembled by universally self-healing and highly stretchable organohydrogel electrodes with record-high temperature-invariant conductivity of ∼965 S/cm. Benefiting from multiple hydrogen bonding and dynamic metal coordination combined with electrochemistry-favorable components and integrated device configuration, the supercapacitor exhibits outstanding long-term stability, high stretchability, instantaneous and complete capacitive self-healability, and real-time mechanical healing at harsh temperatures from -35 to 80 °C. The superiorities in stretchability, self-healability, and all-climate tolerance enable the supercapacitor presented here as the best performer among the flexible supercapacitors reported to date.

9.
Nano Lett ; 22(3): 1433-1442, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-34747171

RESUMO

Skin-mountable capacitive-type strain sensors with great linearity and low hysteresis provide inspiration for the interactions between human and machine. For practicality, high sensing performance, large stretchability, and self-healing are demanded but limited by stretchable electrode and dielectric and interfacial compatibility. Here, we demonstrate an extremely stretchable and self-healing conductor via both hard and soft tactics that combine conductive nanowire assemblies with double dynamic network based on π-π attractions and Ag-S coordination bonds. The obtained conductor outperforms the reported stretchable conductors by delivering an elongation of 3250%, resistance change of 223% at 2000% strain, high durability, and multiresponsive self-healability. Especially, this conductor accommodates large strain of 1500% at extremely knotted and twisted deformations. By sandwiching hydrogel conductors with a newly developed dielectric, ultrahigh stretchability and omni-healability are simultaneously achieved for the first time for a capacitive strain sensor inspired by metal-thiolate coordination chemistry, showing great potentials in wearable electronics and soft robotics.


Assuntos
Nanofios , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Eletrônica , Humanos , Hidrogéis/química , Nanofios/química
10.
ACS Nano ; 15(9): 14766-14775, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34432437

RESUMO

Aqueous zinc batteries (AZBs) are considered promising candidates for large-scale energy storage systems because of their low cost and high safety. However, currently developed AZB cathodes always suffer from the intense charge repulsion of multivalent-ion and complex multiphase electrochemistry, resulting in an insufficient cycling life and impracticable high-sloping discharge profile. Herein, we found that the synthesized ultrathin Bi2O2Se nanosheets can effectively activate stable protons storage in AZBs rather than large zinc ions. This proton-dominated cathode provides an ultraflat discharge plateau (72% capacity proportion) and exhibits long-term cyclability as 90.64% capacity retention after 2300 cycles at 1 A g-1. Further in situ synchrotron X-ray diffraction, ex situ X-ray photoelectronic spectroscopy, and density functional theory confirm the energy storage mechanism regarding the highly reversible proton insertion/extraction process. Benefiting from the proton-dominated fast dynamics, reliable energy supply (>81.5% discharge plateau capacity proportion) is demonstrated at a high rate of up to 10 A g-1 and in the frozen electrolyte below -15 °C. This work provides a potential design of high-performance electrode materials for AZBs.

11.
Front Microbiol ; 12: 694081, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34305858

RESUMO

The Toll/interleukin-1 receptor (TIR) domain is a structural unit responsible for the assembly of signal protein complexes in Toll-like receptor (TLR) and interleukin-1 receptor signaling pathways. TIR domain homologs are found in a considerable number of bacteria and enhance bacterial infection and survival in host organisms. However, whether TIR domain homologs exist in Aeromonas hydrophila, a ubiquitous waterborne bacterium in aquatic environments, remains poorly understood. In this study, a TIR domain protein (TcpAh) was identified from A. hydrophila JBN2301. TIR domain of TcpAh is highly homologous to the counterpart domains in TLRs and myeloid differentiation factor 88 (MyD88). The zebrafish infected with mutant A. hydrophila with tcpAh deletion had a remarkably lower mortality than those infected with the wild-type strain. This result suggests that TcpAh is a crucial virulence factor for A. hydrophila infection. TcpAh exhibited a strong ability to associate with MyD88, tumor necrosis factor receptor-associated factor 3 (TRAF3) and TRAF-associated NF-κB activator-binding kinase 1 (TBK1) in TIR-TIR, TIR-Death domain (DD), and other alternative interactions. This finding suggests that TcpAh extensively interferes with MyD88 and TIR domain-containing adapter inducing interferon (IFN)-ß (TRIF) signaling pathways downstream of TLRs. Consequently, CD80/86 expression was suppressed by TcpAh via attenuating TLR-stimulated NF-κB activation, which ultimately led to the impairment of the major costimulatory signal essential for the initiation of adaptive humoral immunity against A. hydrophila infection. We believe that this study is the first to show a previously unrecognized mechanism underlying A. hydrophila evades from host antibacterial defense by intervening CD80/86 signal, which bridges innate and adaptive immunity. The mechanism will benefit the development of therapeutic interventions for A. hydrophila infection and septicemia by targeting TcpAh homologs.

12.
Nat Commun ; 12(1): 4297, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262049

RESUMO

Self-healability is essential for supercapacitors to improve their reliability and lifespan when powering the electronics. However, the lack of a universal healing mechanism leads to low capacitive performance and unsatisfactory intelligence. Here, we demonstrate a multi-responsive healable supercapacitor with integrated configuration assembled from magnetic Fe3O4@Au/polyacrylamide (MFP) hydrogel-based electrodes and electrolyte and Ag nanowire films as current collectors. Beside a high mechanical strength, MFP hydrogel exhibits fast optical and magnetic healing properties arising from distinct photothermal and magneto-thermal triggered interfacial reconstructions. By growing electroactive polypyrrole nanoparticles into MFP framework as electrodes, the assembled supercapacitor exhibits triply-responsive healing performance under optical, electrical and magnetic stimuli. Notably, the device delivers a highest areal capacitance of 1264 mF cm-2 among the reported healable supercapacitors and restores ~ 90% of initial capacitances over ten healing cycles. These prominent performance advantages along with the facile device-assembly method make this emerging supercapacitor highly potential in the next-generation electronics.

13.
Int J Mol Sci ; 22(14)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34299078

RESUMO

The oxytocin system plays a role in stress responses and behavior modulation. However, the effects of oxytocin signaling on stress adaptation remain unclear. Here, we demonstrated the roles of oxytocin signaling as a biomarker under stress conditions in the peripheral tissues (the gills) and central nervous system (the brain). All the environmental stressors downregulated the expression of oxytocin receptors in the gills, and the alteration of the expression of oxytocin receptors was also found in the brain after the acidic (AC) and high-ammonia (HA) treatments. The number of oxytocin neurons was increased after double-deionized (DI) treatment. By transgenic line, Tg(oxtl:EGFP), we also investigated the projections of oxytocin neurons and found oxytocin axon innervations in various nuclei that might regulate the anxiety levels and aggressiveness of adult zebrafish under different environmental stresses. The oxytocin system integrates physiological responses and behavioral outcomes to ensure environmental adaptation in adult zebrafish. Our study provides insight into oxytocin signaling as a stress indicator upon environmental stressors.


Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/patologia , Neurônios/patologia , Ocitócicos/farmacologia , Ocitocina/farmacologia , Estresse Fisiológico , Animais , Animais Geneticamente Modificados , Encéfalo/efeitos dos fármacos , Meio Ambiente , Neurônios/efeitos dos fármacos , Peixe-Zebra
15.
J Anim Physiol Anim Nutr (Berl) ; 104(1): 44-55, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31701580

RESUMO

In this study, we investigated the effects of Saccharomyces cerevisiae (SC), Bacillus subtilis (BS) and Enterococcus faecalis (EF), singly and in combination, on the dry matter intake (DMI), milk production and composition, and faecal microflora of Saanen dairy goats. Fifty goats were randomly divided into five groups: (a) basal diet (control); (b) basal diet + SC; (c) basal diet + BS; (d) basal diet + EF; and (e) basal diet + mixed probiotics. Each treated animal received 5 g/d of probiotics for a total administration of 5 × 1,011 CFU/goat per day. The inclusion of B. subtilis and E. faecalis in the diet of lactating Saanen goats increased DMI (p < .05). Enhanced milk yield was observed with BS and EF. Milk fat percentage was significantly increased by feeding mixed probiotics compared with the control (p < .05); supplying SC, BS and mixed probiotics enhanced the protein percentage (p < .05). The milk lactose percentage in the SC and BS groups was higher than in the control (p < .05). The amount of milk total solids was higher after feeding EF or mixed probiotics than in the control group (p < .05). Non-fat solids showed no notable differences among groups (p > .05). There was no significant influence on gut bacterial abundance and diversity from adding these three probiotics, singly or in combination. Bacteroidales, Escherichia-Shigella and Christensenellaceae abundances were decreased by supplying these probiotics but Succinivibrionaceae increased. In conclusion, there were positive influences of probiotic feed supplementation on intake, milk performance and intestinal microecology.


Assuntos
Suplementos Nutricionais , Microbioma Gastrointestinal/efeitos dos fármacos , Cabras/fisiologia , Lactação/efeitos dos fármacos , Leite/química , Probióticos , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Feminino
16.
Nat Commun ; 10(1): 2202, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101823

RESUMO

Inspired by smart biological tissues, artificial muscle-like actuators offer fascinating prospects due to their distinctive shape transformation and self-healing function under external stimuli. However, further practical application is hindered by the lack of simple and general routes to fabricate ingenious soft materials with anisotropic responsiveness. Here, we describe a general in situ polymerization strategy for the fabrication of anisotropic hydrogels composed of highly-ordered lamellar network crosslinked by the metal nanostructure assemblies, accompanied with remarkably anisotropic performances on mechanical, optical, de-swelling and swelling behaviors. Owing to the dynamic thiolate-metal coordination as healing motifs, the composites exhibit rapid and efficient multi-responsive self-healing performance under NIR irradiation and low pH condition. Dependent on well-defined anisotropic structures, the hydrogel presents controllable solvent-responsive mechanical actuating performance. Impressively, the integrated device through a healing-induced assembly way can deliver more complicated, elaborate forms of actuation, demonstrating its great potentials as superior soft actuators like smart robots.

17.
Adv Mater ; 31(19): e1900573, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30920707

RESUMO

In addition to a high specific capacitance, a large stretchability and self-healing properties are also essential to improve the practicality and reliability of supercapacitors in portable and wearable electronics. However, the integration of multiple functions into one device remains challenging. Here, the construction of a highly stretchable and real-time omni-healable supercapacitor is demonstrated by sandwiching the polypyrrole-incorporated gold nanoparticle/carbon nanotube (CNT)/poly(acrylamide) (GCP@PPy) hydrogel electrodes with a CNT-free GCP (GP) hydrogel as the electrolyte and chemically soldering an Ag nanowire film to the hydrogel electrode as the current collector. The newly developed dynamic metal-thiolate (M-SR, M = Au, Ag) bond-induced integrated configuration, with an intrinsically powerful electrode and electrolyte, enables the assembled supercapacitor to deliver an areal capacitance of 885 mF cm-2 and an energy density of 123 µWh cm-2 , which are among the highest-reported values for stretchable supercapacitors. Notably, the device exhibits a superhigh stretching strain of 800%, rapid optical healing capability, and significant real-time healability during the charge-discharge process. The exceptional performance combined with the facile assembly method confirms this multifunctional device as the best performer among all the flexible supercapacitors reported to date.

18.
Environ Sci Pollut Res Int ; 26(10): 10306-10318, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30761489

RESUMO

Benzotriazole and its associated derivatives (BTs) are widely used as ultraviolet stabilizers and corrosion inhibitors. They have been extensively found in marine environments and are bioaccumulative through the food chain. However, the toxicities of BTs to marine organisms are seldom identified and no assessment has been conducted for filter-feeding bivalves. In this study, a marine scallop Chlamys nobilis was exposed to 0, 0.01, 0.1, and 1.0 mg/L of BT for 60 days. Effects of BT on endocrine system, cytochrome P450 activity, antioxidant activity, and neural activity of C. nobilis were examined. The results showed that BT exerted significant estrogenic effects on both male and female scallops and inhibited EROD activities of C. nobilis even at 0.01 mg/L level. BT at ≥ 0.01 mg/L levels also caused significant oxidative stress on C. nobilis. Moreover, most of the adverse effects of BT to C. nobilis were found from day 35 and 0.01 mg/L was the lowest concentration with observed effects, showing the long-term toxic effects of BT to C. nobilis. Thus, the adverse effects of BT and its derivatives to marine benthic communities deserve more attention in future research.


Assuntos
Pectinidae/fisiologia , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos , Feminino , Cadeia Alimentar , Alimentos Marinhos , Testes de Toxicidade
19.
Phys Chem Chem Phys ; 20(45): 28832-28839, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30420994

RESUMO

The atomic morphology change in the NiCr alloy surface induced by fluorine-chemisorption was investigated by the ab initio atomistic thermodynamic method to elucidate early-stage corrosion processes of nickel-based alloys in strong oxidizing environment. The surface phase diagrams of Cr-doped Ni(111) surface as a function of fluorine chemical potential were obtained to track the surface structures that are most likely to be fostered in various temperature and pressure conditions. The adsorption of fluorine on the top site of Cr in the alloy surface was the most energetically favorable one. With increasing fluorine chemical potential, more fluorine atoms started to agglomerate in the trapping sink of Cr. Fluorine-fluorine repulsion interaction coupled with strong F-Cr bonding could facilitate a decided morphology modification of the metal substrate. Moreover, an insight into the desorption pathways for potential species revealed that in the presence of fluorine, the dissociation of Cr predominantly stems from the relatively easy desorption in the form of CrF2/CrF3 molecules from the non-passivated Ni-based alloy surface.

20.
Nat Commun ; 9(1): 2974, 2018 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-30061682

RESUMO

Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h-1 can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices.

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