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1.
Plant J ; 116(3): 690-705, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37494542

RESUMEN

Spartina alterniflora is a halophyte that can survive in high-salinity environments, and it is phylogenetically close to important cereal crops, such as maize and rice. It is of scientific interest to understand why S. alterniflora can live under such extremely stressful conditions. The molecular mechanism underlying its high-saline tolerance is still largely unknown. Here we investigated the possibility that high-affinity K+ transporters (HKTs), which function in salt tolerance and maintenance of ion homeostasis in plants, are responsible for salt tolerance in S. alterniflora. To overcome the imprecision and unstable of the gene screening method caused by the conventional sequence alignment, we used a deep learning method, DeepGOPlus, to automatically extract sequence and protein characteristics from our newly assemble S. alterniflora genome to identify SaHKTs. Results showed that a total of 16 HKT genes were identified. The number of S. alterniflora HKTs (SaHKTs) is larger than that in all other investigated plant species except wheat. Phylogenetically related SaHKT members had similar gene structures, conserved protein domains and cis-elements. Expression profiling showed that most SaHKT genes are expressed in specific tissues and are differentially expressed under salt stress. Yeast complementation expression analysis showed that type I members SaHKT1;2, SaHKT1;3 and SaHKT1;8 and type II members SaHKT2;1, SaHKT2;3 and SaHKT2;4 had low-affinity K+ uptake ability and that type II members showed stronger K+ affinity than rice and Arabidopsis HKTs, as well as most SaHKTs showed preference for Na+ transport. We believe the deep learning-based methods are powerful approaches to uncovering new functional genes, and the SaHKT genes identified are important resources for breeding new varieties of salt-tolerant crops.


Asunto(s)
Aprendizaje Profundo , Oryza , Genes de Plantas , Fitomejoramiento , Poaceae/genética , Poaceae/metabolismo , Oryza/genética , Oryza/metabolismo
2.
Anal Chem ; 96(1): 179-187, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38100653

RESUMEN

Achieving accurate detection of different speciations of heavy metal ions (HMIs) in an aqueous solution is an urgent problem due to the different bioavailabilities and physiological toxicity. Herein, we nominated a novel strategy to detect HCrO4- and Cr(OH)2+ at a trace level via the electrochemical sensitive surface constructed by Co3O4-rGO modified with amino and carboxyl groups, which revealed that the interactions between distinct functional groups and different oxygen-containing groups of target ions are conducive to the susceptible and anti-interference detection. The detection sensitivities of 19.46 counts µg-1 L for HCrO4- and 13.44 counts µg-1 L for Cr(OH)2+ were obtained under optimal conditions, while the limits of detection were 0.10 and 0.12 µg L-1, respectively. Satisfactory anti-interference and actual water sample analysis results were obtained. A series of advanced optical techniques like X-ray photoelectron spectroscopy, X-ray absorption near-edge structure technology, and density functional theory calculations under an electric field demonstrated that chemical interactions between groups contribute more to the fixation of target ions than electrical attraction alone. The presence of oxygen-containing groups distinct from simple ionic forms was a critical factor in the selectivity and anti-interference detection. Furthermore, the valence cycle of Co(II)/(III) synergistically boosted the detection performance. This research provides a promising tactic from the microscopic perspective of groups' interactions to accomplish the precise speciation analysis of HMIs in the water environment.

3.
Anal Chem ; 96(13): 5232-5241, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38447030

RESUMEN

Although utilizing nanomaterial-modified electrodes for lead ion detection has achieved great success, most of them are carried out under acidic conditions and ignore the variation of Pb(II) speciation at different pH conditions, leading to the potential inaccuracy of Pb(II) detection in a neutral natural water environment. Thus, designing a novel catalyst with high accuracy for the detection of various forms of the total amount of Pb(II) (Pb2+ and Pb(OH)+) in neutral waters is significant. Herein, Pt nanoclusters (Pt NCs) were elaborately constructed and stabilized on the Co single-atom-doped g-C3N4 with abundant N vacancies (Pt NCs/VN-C3N4), which achieved the ultrasensitive detection (102.16 µM µA-1) of Pb(II) in neutral conditions. The dynamic simulation and theoretical calculations reveal that the parallel deposition of Pb2+ and Pb(OH)+ occurs on the electrode surface modified by Pt NCs/VN-C3N4, and the current peaks of Pb(II) are cocontributed by Pb2+ and Pb(OH)+ species. An "electron inverse" phenomenon in Pt NCs/VN-C3N4 from the VN-C3N4 substrate to Pt NCs endows Pt NCs in an electron-rich state, serving as active centers to promote rapid and efficient reduction for both Pb2+ and Pb(OH)+, facilitating the accurate detection of the total amount of Pb(II) in all forms in the actual water environment.

4.
Plant Biotechnol J ; 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38685729

RESUMEN

Spartina alterniflora is an exo-recretohalophyte Poaceae species that is able to grow well in seashore, but the genomic basis underlying its adaptation to salt tolerance remains unknown. Here, we report a high-quality, chromosome-level genome assembly of S. alterniflora constructed through PacBio HiFi sequencing, combined with high-throughput chromosome conformation capture (Hi-C) technology and Illumina-based transcriptomic analyses. The final 1.58 Gb genome assembly has a contig N50 size of 46.74 Mb. Phylogenetic analysis suggests that S. alterniflora diverged from Zoysia japonica approximately 21.72 million years ago (MYA). Moreover, whole-genome duplication (WGD) events in S. alterniflora appear to have expanded gene families and transcription factors relevant to salt tolerance and adaptation to saline environments. Comparative genomics analyses identified numerous species-specific genes, significantly expanded genes and positively selected genes that are enriched for 'ion transport' and 'response to salt stress'. RNA-seq analysis identified several ion transporter genes including the high-affinity K+ transporters (HKTs), SaHKT1;2, SaHKT1;3 and SaHKT1;8, and high copy number of Salt Overly Sensitive (SOS) up-regulated under high salt conditions, and the overexpression of SaHKT2;4 in Arabidopsis thaliana conferred salt tolerance to the plant, suggesting specialized roles for S. alterniflora to adapt to saline environments. Integrated metabolomics and transcriptomics analyses revealed that salt stress activate glutathione metabolism, with differential expressions of several genes such as γ-ECS, GSH-S, GPX, GST and PCS in the glutathione metabolism. This study suggests several adaptive mechanisms that could contribute our understanding of evolutional basis of the halophyte.

5.
Ann Allergy Asthma Immunol ; 132(3): 368-373.e2, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37949352

RESUMEN

BACKGROUND: The Asian American (AsA) population is heterogenous and rapidly growing; however, little is known regarding childhood asthma burden among AsA ethnic groups. The relation between obesity and asthma in AsA ethnic groups also remains unclear. OBJECTIVE: To evaluate asthma prevalence and the relation of obesity to asthma risk among children in 7 AsA ethnic groups. METHODS: We analyzed data from the California Health Interview Survey from 2011 to 2020. AsA ethnicities were self-reported. Body mass index z-scores, calculated from self-reported height/weight, were used to categorize children by obesity status, based on body mass index-for-age growth charts. Prevalence of self-reported lifetime doctor-diagnosed asthma and asthma attack in the last 12 months was calculated. We performed multivariable logistic regressions adjusting for age and sex. RESULTS: Of 34,146 survey respondents, 12.2% non-Hispanic White and 12.5% AsA children reported lifetime asthma. Among AsA ethnic groups, however, lifetime asthma ranged from 5.1% (Korean American) to 21.5% (Filipino American). Non-Hispanic White children and AsA children had a similar lifetime asthma prevalence (adjusted odds ratio [aOR], 1.05; 95% CI, 0.71-1.55; P = .81), but prevalence was lower in Korean American children (aOR, 0.37; 95% CI, 0.19-0.73; P = .004) and higher in Filipino American children (aOR, 1.97; 95% CI, 1.22-3.17; P = .006). The lifetime asthma prevalence of different AsA ethnic groups persisted even when stratified by obesity status. CONCLUSION: Childhood lifetime asthma prevalence varied among AsA ethnic groups, with lowest prevalence in Korean American children and highest prevalence in Filipino American. Further characterization of asthma burden among AsA ethnic groups may help guide asthma screening and prevention measures and offer new insights into asthma pathogenesis.


Asunto(s)
Asiático , Asma , Niño , Humanos , Estados Unidos , Etnicidad , Asma/epidemiología , Obesidad/epidemiología , Prevalencia , California/epidemiología
6.
Anal Chem ; 95(7): 3666-3674, 2023 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-36656141

RESUMEN

Traditional nanomodified electrodes have made great achievements in electrochemical stripping voltammetry of sensing materials for As(III) detection. Moreover, the intermediate states are complicated to probe because of the ultrashort lifetime and complex reaction conditions of the electron transfer process in electroanalysis, which seriously hinder the identification of the actual active site. Herein, the intrinsic interaction of highly sensitive analytical behavior of nanomaterials is elucidated from the perspective of electronic structure through density functional theory (DFT) and gradient boosting regression (GBR). It is revealed that the atomic radius, d-band center (εd), and the largest coordinative TM-N bond length play a crucial role in regulating the arsenic reduction reaction (ARR) performance by the established ARR process for 27 sets of transition-metal single atoms supported on N-doped graphene. Furthermore, the database composed of filtered intrinsic electronic structural properties and the calculated descriptors of the central metal atom in TM-N4-Gra were also successfully extended to oxygen evolution reaction (OER) systems, which effectively verified the reliability of the whole approach. Generally, a multistep workflow is developed through GBR models combined with DFT for valid screening of sensing materials, which will effectively upgrade the traditional trial-and-error mode for electrochemical interface designing.

7.
Opt Express ; 31(5): 8307-8324, 2023 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-36859946

RESUMEN

We present a systematic investigation of the resonant radiation emitted by localized soliton-like wave-packets supported by second-harmonic generation in the cascading regime. We emphasize a general mechanism which allows for the resonant radiation to grow without the need for higher-order dispersion, primarily driven by the second-harmonic component, while radiation is also shed around the fundamental-frequency component through parametric down-conversion processes. The ubiquity of such a mechanism is revealed with reference to different localized waves such as bright solitons (both fundamental and second-order), Akhmediev breathers, and dark solitons. A simple phase matching condition is put forward to account for the frequencies radiated around such solitons, which agrees well with numerical simulations performed against changes of material parameters (say, phase mismatch, dispersion ratio). The results provide explicit understanding of the mechanism of soliton radiation in quadratic nonlinear media.

8.
Anal Chem ; 94(7): 3211-3218, 2022 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-35104121

RESUMEN

Vacancy and doping engineering are promising pathways to improve the electrocatalytic ability of nanomaterials for detecting heavy metal ions. However, the effects of the electronic structure and the local coordination on the catalytic performance are still ambiguous. Herein, cubic selenium vacancy-rich CoSe2 (c-CoSe2-x) and P-doped orthorhombic CoSe2-x (o-CoSe2-x|P) were designed via vacancy and doping engineering. An o-CoSe2-x|P-modified glass carbon electrode (o-CoSe2-x|P/GCE) acquired a high sensitivity of 1.11 µA ppb-1 toward As(III), which is about 40 times higher than that of c-CoSe2-x, outperforming most of the reported nanomaterial-modified glass carbon electrodes. Besides, o-CoSe2-x|P/GCE displayed good selectivity toward As(III) compared with other divalent heavy metal cations, which also exhibited excellent stability, repeatability, and practicality. X-ray absorption fine structure spectroscopy and density functional theory calculation demonstrate that electrons transferred from Co and Se to P sites through Co-P and Se-P bonds in o-CoSe2-x|P. P sites obtained plentiful electrons to form active centers, which also had a strong orbital coupling with As(III). In the detection process, As(III) was bonded with P and reduced by the electron-rich sites in o-CoSe2-x|P, thus acquiring a reinforced electrochemical sensitivity. This work provides an in-depth understanding of the influence of the intrinsic physicochemical properties of sensitive materials on the behavior of electroanalysis, thus offering a direct guideline for creating active sites on sensing interfaces.


Asunto(s)
Electrónica , Electrones , Teoría Funcional de la Densidad , Espectroscopía de Absorción de Rayos X , Rayos X
9.
Anal Chem ; 94(40): 13631-13641, 2022 10 11.
Artículo en Inglés | MEDLINE | ID: mdl-36150119

RESUMEN

Constructing high-effective electrode sensing interfaces has been considered an effective method for electrochemical detection toward heavy metal ions (HMIs). However, most research has been devoted to enhancing the stripping currents of HMIs by simply improving the adsorptive capacity and conductivity of the electrode modified materials, while lacking theoretical guidelines in fabricating catalytic sensing interfaces. Besides, the understanding of detection mechanisms is quite unscientific from the perspective of catalysis. This perspective summarizes five general strategies in designing highly efficient sensing interfaces in the recent five years, including modulating crystal phases, orientations and planes, defect engineering, ionic valence state cycle engineering, adsorption in situ catalysis strategy, and construction of atomic level catalytic active sites. What's more, the catalytic mechanisms for improving the signals of HMIs, such as boosting the electron transfer rates and conversion rates, lowering the energy barriers, etc., are introduced and emphasized. This study has a great significance in directionally controlling functionalized electrochemical sensors to achieve excellent sensitivity and selectivity in detecting environmental pollutants from the view of catalysis, and it also brings enlightenments and guidance to develop new electroanalytical methods.


Asunto(s)
Contaminantes Ambientales , Metales Pesados , Catálisis , Electrodos , Iones/química , Metales Pesados/química
10.
Anal Chem ; 94(16): 6225-6233, 2022 04 26.
Artículo en Inglés | MEDLINE | ID: mdl-35404584

RESUMEN

Interference among multiple heavy metal ions (HMIs) is a significant problem that must be solved in electroanalysis, which extremely restricts the practical popularization of electrochemical sensors. However, due to the limited exploration of the intrinsic mechanism, it is still difficult to confirm the influencing factors. In this work, a series of experimental and theoretical electroanalysis models have been established to investigate the electroanalysis results of Cu(II), Cd(II), As(III), and their mixtures, which were based on the simple structure and stable coordination of nickel single-atom catalysts. X-ray absorption spectroscopy and density functional theory calculations were used to reveal the underlying detection mechanism of the 50-fold boosting effect of Cu(II) on As(III) while Cd(II) inhibits As(III). Combining the application of the thermodynamic model and Fourier transform infrared reflection, the specific interaction of the nanomaterials and HMIs on the interface is considered to be the fundamental source of the interference. This work opens up a new way of thinking about utilizing the unique modes of interplay between nanomaterials and HMIs to achieve anti-interference intelligent electrodes in stripping analysis.


Asunto(s)
Metales Pesados , Materiales Inteligentes , Cadmio/química , Iones , Metales Pesados/química , Termodinámica
11.
Opt Lett ; 47(10): 2370-2373, 2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-35561353

RESUMEN

We show that two-color Peregrine solitary waves in quadratic nonlinear media can resonantly radiate dispersive waves even in the absence of higher-order dispersion, owing to a phase-matching mechanism that involves the weaker second-harmonic component. We give very simple criteria for calculating the radiated frequencies in terms of material parameters, finding excellent agreement with numerical simulations.

12.
Anal Chem ; 93(41): 14014-14023, 2021 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-34607426

RESUMEN

An atomic-level Au nanocluster, as an excellent photocatalyst, is generally not considered as an efficient electrocatalyst due to its poor stability. Herein, a method is proposed to stabilize abundant Au25 on Fe2O3 nanoplates (Au25/OV-Fe2O3) successfully with oxygen vacancies (OV) created. Au25/OV-Fe2O3 shows superhigh catalysis in the electrochemical reduction toward As(III). The record-breaking sensitivity (161.42 µA ppb-1) is two orders of magnitude higher than currently reported, where an ultratrace limit of detection (9 ppt) is obtained, suggesting promising applications in the analysis of organic and bioactive substances. The stability of Au25 is attributed to the Au-Fe bond formed after loading Au25 nanoclusters on Fe2O3 nanoplates through "electron compensation" and bond length (Au-S) shortening. Moreover, the ligand S atoms in Au25 nanoclusters significantly contribute to the reduction of As(III). The fantastic stability and superior catalytic ability of Au25/OV-Fe2O3 provide guidelines to stabilize Au nanoclusters on metal oxides, indicating their potential electroanalytical applications.


Asunto(s)
Oro , Oxígeno , Catálisis , Ligandos
13.
Anal Chem ; 93(45): 15115-15123, 2021 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-34714618

RESUMEN

Designing new catalysts with high activity and stability is crucial for the effective analysis of environmental pollutants under mild conditions. Here, we developed a superior catalyst of Pt single atoms anchored on MoS2 (Pt1/MoS2) to catalyze the determination of As(III). A detection sensitivity of 3.31 µA ppb-1 was obtained in acetate buffer solution at pH 6.0, which is the highest compared with those obtained by other Pt-based nanomaterials currently reported. Pt1/MoS2 exhibited excellent electrochemical stability during the detection process of As(III), even in the coexistence of Cu(II), Pb(II), and Hg(II). X-ray absorption fine structure spectroscopy and theoretical calculations revealed that Pt single atoms were stably fixed by four S atoms and activated the adjacent S atoms. Then, Pt and S atoms synergistically interacted with O and As atoms, respectively, and transferred some electrons to H3AsO3, which change the rate-determining step of H3AsO3 reduction and reduce reaction energy barriers, thereby promoting rapid and efficient accumulation for As(0). Compared with Pt nanoparticles, the weaker interaction between arsenic species and Pt1/MoS2 enabled the effortless regeneration and cyclic utilization of active centers, which is more favorable for the oxidation of As(0). This work provides inspiration for developing highly efficient sensing platforms from the perspective of atomic-level catalysis and affords references to explore the detection mechanism of such contaminants.


Asunto(s)
Arsenicales , Nanoestructuras , Arsenicales/química , Catálisis , Molibdeno , Oxidación-Reducción , Platino (Metal)
14.
Anal Chem ; 92(24): 16089-16096, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33166462

RESUMEN

Modulating the active sites of oxygen vacancies (OVs) to enhance the catalytic properties of nanomaterials has attracted much research interest in various fields, but its intrinsic catalytic mechanism is always neglected. Herein, we establish an efficient strategy to promote the electrochemical detection of Pb(II) by regulating the concentration of OVs in α-MoO3 nanorods via doping Ce3+/Ce4+ ions. α-MoO3 with the Ce-doped content of 9% (C9M) exhibited the highest detection sensitivity of 106.64 µM µA-1 for Pb(II), which is higher than that achieved by other metal oxides and most precious metal nanomaterials. It is found that C9M possessed the highest concentration of OVs, which trapped some electrons for strong affinity interaction with Pb(II) and provided numerous atomic level interfaces of high surface free energy for catalysis reactions. X-ray absorption fine structure spectra and density functional theory calculation indicate that Pb(II) was bonded with the surface-activated oxygen atoms (Os) around Ce ions and obtained some electrons from Os. Besides, the longer Pb-O bonds on C9M were easier to break, causing a low desorption energy barrier to effectively accelerate Pb(II) desorbing to the electrode surface. This study helps to understand the changes in electronic structure and catalytic performance with heteroatom doping and OVs in chemically inert oxides and provide a reference for designing high-active electrocatalytic interfaces to realize ultrasensitive analysis of environmental contaminants.

15.
Biochem Biophys Res Commun ; 533(3): 296-303, 2020 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-32958258

RESUMEN

Pseudomonas aeruginosa is the main conditional pathogen of immunodeficiency individuals. The mechanisms governing immune response to P. aeruginosa infection by macrophages remain incompletely defined. Herein, we demonstrate that protein tyrosine phosphatase-1B (PTP1B) is a critical negative regulator of P. aeruginosa infection response by macrophages. PTP1B-deficient macrophages display greatly enhanced bacterial phagocytosis and killing, accompanied by increased lysosome formation during P. aeruginosa infection. We also found that PTP1B repressed nitric oxide (NO) production and nitric oxide synthase (iNOS) induction following P. aeruginosa infection. PTP1B deficiency tended to upregulate the production of TRIF-interferon (IFN) pathway cytokines and chemokines, including IFN-ß and interferon γ-inducible protein 10 (CXCL10, IP-10). Unexpectedly, the phosphorylation level of STAT1 was not regulated by PTP1B. In vivo experiments also confirmed that the regulatory function of PTP1B was not dependent on STAT1. These findings demonstrate that STAT1 is dispensable for negative regulation of P. aeruginosa clearance by macrophages.


Asunto(s)
Interacciones Huésped-Patógeno/genética , Macrófagos/inmunología , Proteína Tirosina Fosfatasa no Receptora Tipo 1/genética , Infecciones por Pseudomonas/genética , Pseudomonas aeruginosa/inmunología , Factor de Transcripción STAT1/genética , Animales , Quimiocina CXCL10/genética , Quimiocina CXCL10/inmunología , Quimiocina CXCL2/genética , Quimiocina CXCL2/inmunología , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno/inmunología , Humanos , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-1beta/genética , Interleucina-1beta/inmunología , Interleucina-6/genética , Interleucina-6/inmunología , Macrófagos/microbiología , Ratones , Ratones Noqueados , Óxido Nítrico/inmunología , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/genética , Óxido Nítrico Sintasa de Tipo II/inmunología , Fagocitosis , Cultivo Primario de Células , Proteína Tirosina Fosfatasa no Receptora Tipo 1/deficiencia , Proteína Tirosina Fosfatasa no Receptora Tipo 1/inmunología , Infecciones por Pseudomonas/inmunología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/patogenicidad , Factor de Transcripción STAT1/inmunología , Transducción de Señal , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología
16.
Small ; 16(25): e2001035, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32406188

RESUMEN

Heavy metal ions (HMIs) are one of the major environmental pollution problems currently faced. To monitor and control HMIs, rapid and reliable detection is required. Electrochemical analysis is one of the promising methods for on-site detection and monitoring due to high sensitivity, short response time, etc. Recently, nanometal oxides with special surface physicochemical properties have been widely used as electrode modifiers to enhance sensitivity and selectivity for HMIs detection. In this work, recent advances in the electrochemical detection of HMIs using nanometal oxides, which are attributed to specific crystal facets and phases, surficial defects and vacancies, and oxidation state cycle, are comprehensively summarized and discussed in aspects of synthesis, characterization, electroanalysis application, and mechanism. Moreover, the challenges and opportunities for the development and application of nanometal oxides with functional surface physicochemical properties in electrochemical determination of HMIs are presented.

17.
Small ; 16(7): e1906830, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31971669

RESUMEN

Metal hydroxide nanomaterials are widely applied in the energy and environment fields. The electrochemical performance of such materials is strongly dependent on their crystal phases. However, as there are always multiple factors relating to the phase-dependent electrochemistry, it is still difficult to identify the determining one. The well-defined crystal phases of α- and ß-FeOOH nanorods are characterized through the transmission electron microscopy by a series of rotation toward one rod, where the cross-section shape and the growth direction along the [001] crystalline are first verified for 1D FeOOH nanostructures. The electrosensitivity of the two materials toward Pb(II) is tested, where α-FeOOH performs an outstanding sensitivity whilst it is only modest for ß-FeOOH. Experiments via Fourier transform infrared spectroscopy, X-ray absorption fine structure (XAFS), etc., show that α-FeOOH presents a larger Pb(II) adsorption capacity due to more surficial hydroxyl groups and weaker PbO bond strength. The reaction kinetics are simulated and the adsorption capacity is found to be the determining factor for the distinct Pb(II) sensitivities. Combining experiment with simulation, this work reveals the physical insights of the phase-dependent electrochemistry for FeOOH and provides guidelines for the functional application of metal hydroxide nanomaterials.

18.
Phys Rev Lett ; 124(11): 113901, 2020 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-32242694

RESUMEN

We report the universal emergence of anomalous fundamental Peregrine solitons, which can exhibit an unprecedentedly ultrahigh peak amplitude comparable to any higher-order rogue wave events, in the vector derivative nonlinear Schrödinger system involving the self-steepening effect. We present the exact explicit rational solutions on either a continuous-wave or a periodical-wave background, for a broad range of parameters. We numerically confirm the buildup of anomalous Peregrine solitons from strong initial harmonic perturbations, despite the onset of competing modulation instability. Our results may stimulate the experimental study of such Peregrine soliton anomaly in birefringent crystals or other similar vector systems.

19.
Environ Res ; 188: 109774, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32615354

RESUMEN

The precipitation of struvite (MgNH4PO4·6H2O) consumes many chemicals to completely remove ammonium and phosphate from urine and has the difficulty in solid separation from solution. This study proposed an alternative approach for the complete nutrient removal through recycling use of microwave-induced decomposition product of struvite pellet with sizes of 2-4 mm. Results showed that microwave radiation effectively decomposed the struvite pellet in an alkaline solution within 8 min. An increase in microwave power and NaOH concentration enhanced the decomposition. The double-layer structure of the pellet led to multiple paths of struvite decomposition. Active components of the decomposition product were newberyite, brucite, and amorphous MgNaPO4 and MgHPO4. The removal efficiencies of ammonium and phosphate from urine both reached 93% using the decomposition product at optimized P/N ratio and pH. Maximum recycles of 4 were recommended because further decomposition of the regenerated struvite pellets induced high losses of magnesium and phosphate. Calculations showed that the total cost of chemical consumption of the proposed approach was reduced by 47% compared with that of a conventional chemical struvite precipitation. Moreover, the volume index of the regenerated struvite pellets was 15 mL/gP which was much lower than that of conventional struvite fines (116 mL/gP), thereby indicating a better solid-liquid separation ability. Therefore, recycling of struvite pellets combining with microwave decomposition was chemical saving and easily separating of solid from liquid for the complete removal of nutrients from urine.


Asunto(s)
Compuestos de Amonio , Microondas , Fosfatos , Reciclaje , Estruvita , Eliminación de Residuos Líquidos
20.
Physica A ; 544: 123379, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32308254

RESUMEN

A stochastic susceptible-infectious-recovered epidemic model with nonlinear incidence rate is formulated to discuss the effects of temporary immunity, vaccination, and Le.´vy jumps on the transmission of diseases. We first determine the existence of a unique global positive solution and a positively invariant set for the stochastic system. Sufficient conditions for extinction and persistence in the mean of the disease are then achieved by constructing suitable Lyapunov functions. Based on the analysis, we conclude that noise intensity and the validity period of vaccination greatly influence the transmission dynamics of the system.

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