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1.
Sci Total Environ ; 926: 171746, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38521276

RESUMEN

Understanding the diversity and functions of hydrocarbon-degrading microorganisms in marine environments is crucial for both advancing knowledge of biogeochemical processes and improving bioremediation methods. In this study, we leveraged nearly 20,000 metagenome-assembled genomes (MAGs), recovered from a wide array of marine samples across the global oceans, to map the diversity of aerobic hydrocarbon-degrading microorganisms. A broad bacterial diversity was uncovered, with a notable preference for degrading aliphatic hydrocarbons over aromatic ones, primarily within Proteobacteria and Actinobacteriota. Three types of broad-spectrum hydrocarbon-degrading bacteria were identified for their ability to degrade various hydrocarbons and possession of multiple copies of hydrocarbon biodegradation genes. These bacteria demonstrate extensive metabolic versatility, aiding their survival and adaptability in diverse environmental conditions. Evidence of gene duplication and horizontal gene transfer in these microbes suggested a potential enhancement in the diversity of hydrocarbon-degrading bacteria. Positive correlations were observed between the abundances of hydrocarbon-degrading genes and environmental parameters such as temperature (-5 to 35 °C) and salinity (20 to 42 PSU). Overall, our findings offer valuable insights into marine hydrocarbon-degrading microorganisms and suggest considerations for selecting microbial strains for oil pollution remediation.


Asunto(s)
Metagenoma , Petróleo , Hidrocarburos/metabolismo , Bacterias/genética , Bacterias/metabolismo , Biodegradación Ambiental , Océanos y Mares , Petróleo/metabolismo
2.
Nano Lett ; 24(10): 3204-3212, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38416569

RESUMEN

The flicker frequency of incident light constitutes a critical determinant in biology. Nevertheless, the exploration of methods to simulate external light stimuli with varying frequencies and develop artificial retinal neurons capable of responsive behavior remains an open question. This study presents an artificial neuron comprising organic phototransistors. The triggering properties of neurons are modulated by optical input, enabling them to execute rudimentary synaptic functions, emulating the biological characteristics of retinal neurons. The artificial retinal neuron exhibits varying responses to incoming light frequencies, allowing it to replicate the persistent visual behavior of the human eye and facilitating image discrimination. Additionally, through seamless integration with circuitry, it can execute motion recognition on a machine cart, preventing collisions with high-speed obstacles. The artificial retinal neuron offers a cost-effective and energy-efficient route for future mobile robot processors.


Asunto(s)
Retina , Visión Ocular , Humanos , Neuronas/fisiología
3.
Trends Microbiol ; 32(4): 321-324, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38290879

RESUMEN

Deep-sea ecosystems are home to a diverse community of microorganisms. These microbes are not only fundamental to ecological processes but also a treasure trove of natural products and enzymes with significant scientific and industrial applications. This forum focuses on the vast diversity of deep-sea microbes and their potential for bioprospecting. It also discusses threats posed by climate change and deep-sea mining to deep-sea microbial genetic resources, and proposes future research directions.


Asunto(s)
Productos Biológicos , Bioprospección , Ecosistema , Genética Microbiana , Cambio Climático
4.
Technol Health Care ; 32(1): 9-18, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37393451

RESUMEN

BACKGROUND: At present, robust quality criteria and methods for the assessment of Peak inspiratory flow meter performance are lacking. OBJECTIVE: A standard flow-volume simulator for quality control analyses of an inhalation assessment device was utilized with different simulated resistance levels in order to propose a quality testing method and associated standard for this device type. METHODS: A standard flow-volume simulator was utilized to assess the performance of an In-Check DIAL® (Device I) and an intelligent inhalation assessment device (Device P) at a fixed volume and flow rate. Indices used to evaluate these two instruments included repeatability, accuracy, linearity, and impedance. RESULTS: Both devices exhibited good repeatability (<± 3 L/min). The difference between test results and standard simulator values for Device P was less than ± 5 L/min at resistance level R1 but higher than ± 5 L/min at resistance levels R2-5, while Device I were greater than 5 L/min at all resistance levels. The relative error for Device P was <± 10% at resistance levels R1, R2, and R4, but > 10% at resistance levels R3 and R5. The relative error values for Device I at all five resistance levels were > 10%. Device P passed the linearity test at the R2 resistance level, while Device I partially passed the linearity test at all five resistance levels. CONCLUSION: Standard monitoring methods and standards provide a valuable approach to the more reliable clinical assessment and application of these instruments.


Asunto(s)
Nebulizadores y Vaporizadores , Humanos , Pruebas de Función Respiratoria
5.
Sci Data ; 10(1): 596, 2023 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-37684262

RESUMEN

Cold seeps harbor abundant and diverse microbes with tremendous potential for biological applications and that have a significant influence on biogeochemical cycles. Although recent metagenomic studies have expanded our understanding of the community and function of seep microorganisms, knowledge of the diversity and genetic repertoire of global seep microbes is lacking. Here, we collected a compilation of 165 metagenomic datasets from 16 cold seep sites across the globe to construct a comprehensive gene and genome catalog. The non-redundant gene catalog comprised 147 million genes, and 36% of them could not be assigned to a function with the currently available databases. A total of 3,164 species-level representative metagenome-assembled genomes (MAGs) were obtained, most of which (94%) belonged to novel species. Of them, 81 ANME species were identified that cover all subclades except ANME-2d, and 23 syntrophic SRB species spanned the Seep-SRB1a, Seep-SRB1g, and Seep-SRB2 clades. The non-redundant gene and MAG catalog is a valuable resource that will aid in deepening our understanding of the functions of cold seep microbiomes.


Asunto(s)
Genómica , Metagenoma , Bases de Datos Factuales , Conocimiento , Metagenómica , Bacterias , Archaea
6.
ISME J ; 17(10): 1774-1784, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37573455

RESUMEN

Deep sea cold seep sediments have been discovered to harbor novel, abundant, and diverse bacterial and archaeal viruses. However, little is known about viral genetic features and evolutionary patterns in these environments. Here, we examined the evolutionary ecology of viruses across active and extinct seep stages in the area of Haima cold seeps in the South China Sea. A total of 338 viral operational taxonomic units are identified and linked to 36 bacterial and archaeal phyla. The dynamics of host-virus interactions are informed by diverse antiviral defense systems across 43 families found in 487 microbial genomes. Cold seep viruses are predicted to harbor diverse adaptive strategies to persist in this environment, including counter-defense systems, auxiliary metabolic genes, reverse transcriptases, and alternative genetic code assignments. Extremely low nucleotide diversity is observed in cold seep viral populations, being influenced by factors including microbial host, sediment depth, and cold seep stage. Most cold seep viral genes are under strong purifying selection with trajectories that differ depending on whether cold seeps are active or extinct. This work sheds light on the understanding of environmental adaptation mechanisms and evolutionary patterns of viruses in the sub-seafloor biosphere.


Asunto(s)
Agua de Mar , Virus , Humanos , Agua de Mar/microbiología , Sedimentos Geológicos/microbiología , Biodiversidad , Metano , Filogenia , Bacterias/genética , Virus/genética , ARN Ribosómico 16S/genética
7.
Small ; 19(38): e2207185, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37226387

RESUMEN

Two-dimensional (2D) Ruddlesden-Popper (RP) layered halide perovskite has attracted wide attentions due to its unique structure and excellent optoelectronic properties. With inserting organic cations, inorganic octahedrons are forced to extend in a certain direction, resulting in an asymmetric 2D perovskite crystal structure and causing spontaneous polarization. The pyroelectric effect resulted from spontaneous polarization exhibits a broad prospect in the application of optoelectronic devices. Herein, 2D RP polycrystalline perovskite (BA)2 (MA)3 Pb4 I13 film with excellent crystal orientation is fabricated by hot-casting deposition, and a class of 2D hybrid perovskite photodetectors (PDs) with pyro-phototronic effect is proposed, achieving temperature and light detection with greatly improved performance by coupling multiple energies. Because of the pyro-phototronic effect, the current is ≈35 times to that of the photovoltaic effect current under 0 V bias. The responsivity and detectivity are 12.7 mA W-1 and 1.73 × 1011 Jones, and the on/off ratio can reach 3.97 × 103 . Furthermore, the influences of bias voltage, light power density, and frequency on the pyro-phototronic effect of 2D RP polycrystalline perovskite PDs are explored. The coupling of spontaneous polarization and light facilitates photo-induced carrier dissociation and tunes the carrier transport process, making 2D RP perovskites a competitive candidate for next-generation photonic devices.

8.
Nat Commun ; 14(1): 1127, 2023 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-36854684

RESUMEN

Deep sea cold seep sediments host abundant and diverse microbial populations that significantly influence biogeochemical cycles. While numerous studies have revealed their community structure and functional capabilities, little is known about genetic heterogeneity within species. Here, we examine intraspecies diversity patterns of 39 abundant species identified in sediment layers down to 430 cm below the sea floor across six cold seep sites. These populations are grouped as aerobic methane-oxidizing bacteria, anaerobic methanotrophic archaea and sulfate-reducing bacteria. Different evolutionary trajectories are observed at the genomic level among these physiologically and phylogenetically diverse populations, with generally low rates of homologous recombination and strong purifying selection. Functional genes related to methane (pmoA and mcrA) and sulfate (dsrA) metabolisms are under strong purifying selection in most species investigated. These genes differ in evolutionary trajectories across phylogenetic clades but are functionally conserved across sites. Intrapopulation diversification of genomes and their mcrA and dsrA genes is depth-dependent and subject to different selection pressure throughout the sediment column redox zones at different sites. These results highlight the interplay between ecological processes and the evolution of key bacteria and archaea in deep sea cold seep extreme environments, shedding light on microbial adaptation in the subseafloor biosphere.


Asunto(s)
Aclimatación , Desulfovibrio , Filogenia , Archaea/genética , Sulfatos
9.
J Asthma Allergy ; 16: 159-172, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36718312

RESUMEN

Purpose: To develop and internally validate a nomogram for predicting the risk of incorrect inhalation techniques in patients with chronic airway diseases. Methods: A total of 206 patients with chronic airway diseases treated with inhaled medications were recruited in this study. Patients were divided into correct (n=129) and incorrect (n=77) cohorts based on their mastery of inhalation devices, which were assessed by medical professionals. Data were collected on the basis of questionnaires and medical records. The least absolute shrinkage and selection operator method (LASSO) and multivariate logistic regression analyses were conducted to identify the risk factors of incorrect inhalation techniques. Then, calibration curve, Harrell's C-index, area under the receiver operating characteristic curve (AUC), decision curve analysis (DCA) and bootstrapping validation were applied to assess the apparent performance, clinical validity and internal validation of the predicting model, respectively. Results: Seven risk factors including age, education level, drug cognition, self-evaluation of curative effect, inhalation device use instruction before treatment, post-instruction evaluation and evaluation at return visit were finally determined as the predictors of the nomogram prediction model. The ROC curve obtained by this model showed that the AUC was 0.814, with a sensitivity of 0.78 and specificity of 0.75. In addition, the C-index was 0.814, with a Z value of 10.31 (P<0.001). It was confirmed to be 0.783 by bootstrapping validation, indicating that the model had good discrimination and calibration. Furthermore, analysis of DCA showed that the nomogram had good clinical validity. Conclusion: The application of the developed nomogram to predict the risk of incorrect inhalation techniques during follow-up visits is feasible.

10.
Microb Ecol ; 85(2): 465-477, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35113183

RESUMEN

Reef sediments, the home for microbes with high abundances, provide an important source of carbonates and nutrients for the growth and maintenance of coral reefs. However, there is a lack of systematic research on the composition of microbial community in sediments of different geographic sites and their potential effect on nutrient recycling and health of the coral reef ecosystem. In combination of biogeochemical measurements with gene- and genome-centric metagenomics, we assessed microbial community compositions and functional diversity, as well as profiles of antibiotic resistance genes in surface sediments of 16 coral reef sites at different depths from the Xisha islands in the South China Sea. Reef sediment microbiomes are diverse and novel at lower taxonomic ranks, dominated by Proteobacteria and Planctomycetota. Most reef sediment bacteria potentially participate in biogeochemical cycling via oxidizing various organic and inorganic compounds as energy sources. High abundances of Proteobacteria (mostly Rhizobiales and Woeseiales) are metabolically flexible and contain rhodopsin genes. Various classes of antibiotic resistance genes, hosted by diverse bacterial lineages, were identified to confer resistance to multidrug, aminoglycoside, and other antibiotics. Overall, our findings expanded the understanding of reef sediment microbial ecology and provided insights for their link to the coral reef ecosystem health.


Asunto(s)
Antozoos , Microbiota , Animales , Arrecifes de Coral , Ecosistema , Arena , Metagenómica , Bacterias/genética , Proteobacteria , Antozoos/microbiología
11.
Microbiol Spectr ; 10(6): e0338822, 2022 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-36301121

RESUMEN

Members from the Inoviridae family with striking features are widespread, highly diverse, and ecologically pervasive across multiple hosts and environments. However, a small number of inoviruses have been isolated and studied. Here, a filamentous phage infecting Alteromonas abrolhosensis, designated ϕAFP1, was isolated from the South China Sea and represented a novel genus of Inoviridae. ϕAFP1 consisted of a single-stranded DNA genome (5986 bp), encoding eight putative ORFs. Comparative analyses revealed ϕAFP1 could be regarded as genetic mosaics having homologous sequences with Ralstonia and Stenotrophomonas phages. The temporal transcriptome analysis of A. abrolhosensis to ϕAFP1 infection revealed that 7.78% of the host genes were differentially expressed. The genes involved in translation processes, ribosome pathways, and degradation of multiple amino acid pathways at the plateau period were upregulated, while host material catabolic and bacterial motility-related genes were downregulated, indicating that ϕAFP1 might hijack the energy of the host for the synthesis of phage proteins. ϕAFP1 exerted step-by-step control on host genes through the appropriate level of utilizing host resources. Our study provided novel information for a better understanding of filamentous phage characteristics and phage-host interactions. IMPORTANCE Alteromonas is widely distributed and plays a vital role in biogeochemical in marine environments. However, little information about Alteromonas phages is available. Here, we isolated and characterized the biological characteristics and genome sequence of a novel inovirus infecting Alteromonas abrolhosensis, designated ϕAFP1, representing a novel viral genus of Inoviridae. We then presented a comprehensive view of the ϕAFP1 phage-Alteromonas abrolhosensis interactions, elucidating reprogramed host metabolism and motility. Our study provided novel information for better comprehension of filamentous phage characteristics and phage-host interactions.


Asunto(s)
Alteromonas , Bacteriófagos , Inovirus , Inovirus/genética , China , Genoma Viral , Filogenia
12.
Phys Chem Chem Phys ; 24(39): 24123-24129, 2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36193645

RESUMEN

The stability of Sn-based perovskites has always been the main obstacle to their application. Interface engineering is a very effective method for improving the stability of perovskites and the efficiency of batteries. Two-dimensional (2D) monolayer SnS is selected as a surface-covering layer for the CsSnI3 lead-free perovskite. The structure, electronic properties, and stability of the CsSnI3-SnS heterostructure are studied using density functional theory. Due to the different contact interfaces (SnI2 and CsI interfaces) of CsSnI3, the interface electronic-transmission characteristics are inconsistent in the CsSnI3-SnS heterostructure. Because of the difference in work functions, electrons flow at the interface of the heterostructure, forming a built-in electric field. The heterostructures form a type-I energy-level arrangement. Under the action of an electric field in the CsI-SnS heterostructure, electrons at the CsI interface recombine with holes at the SnS interface; however, the holes of the SnI2 interface and the electrons of the SnS interface are easily recombined in the SnI2-SnS heterostructure. Moreover, monolayer SnS can enhance the light absorption of the CsSnI3-SnS heterostructure. Monolayer SnS can inhibit the migration of iodine ions and effectively improve the structural stability of the SnI2-SnS interface heterostructure. This work provides a new theoretical basis for improving the stability of lead-free perovskites.

13.
Nat Commun ; 13(1): 4885, 2022 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-35985998

RESUMEN

Microbially mediated nitrogen cycling in carbon-dominated cold seep environments remains poorly understood. So far anaerobic methanotrophic archaea (ANME-2) and their sulfate-reducing bacterial partners (SEEP-SRB1 clade) have been identified as diazotrophs in deep sea cold seep sediments. However, it is unclear whether other microbial groups can perform nitrogen fixation in such ecosystems. To fill this gap, we analyzed 61 metagenomes, 1428 metagenome-assembled genomes, and six metatranscriptomes derived from 11 globally distributed cold seeps. These sediments contain phylogenetically diverse nitrogenase genes corresponding to an expanded diversity of diazotrophic lineages. Diverse catabolic pathways were predicted to provide ATP for nitrogen fixation, suggesting diazotrophy in cold seeps is not necessarily associated with sulfate-dependent anaerobic oxidation of methane. Nitrogen fixation genes among various diazotrophic groups in cold seeps were inferred to be genetically mobile and subject to purifying selection. Our findings extend the capacity for diazotrophy to five candidate phyla (Altarchaeia, Omnitrophota, FCPU426, Caldatribacteriota and UBA6262), and suggest that cold seep diazotrophs might contribute substantially to the global nitrogen balance.


Asunto(s)
Ecosistema , Sedimentos Geológicos , Archaea/metabolismo , Sedimentos Geológicos/microbiología , Metano/metabolismo , Nitrógeno/metabolismo , Oxidación-Reducción , Filogenia , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismo , Agua de Mar/microbiología , Sulfatos/metabolismo
14.
BMC Pulm Med ; 22(1): 218, 2022 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-35659277

RESUMEN

BACKGROUND: To understand the accuracy of volume calibration syringes used in China and compare the difference between new and old volume calibration syringes, technical testing was performed on volume calibration syringes in clinical lung function instruments. MATERIALS AND METHODS: A standard validator device (Model 1180, Hans Rudolph, USA) was used to perform leak testing and volume accuracy testing for calibration syringes. Sixteen volume calibration syringes from 8 brands (CareFusion in Germany, Vyaire in Germany, Yaeger in Germany, Vitalograph in the United Kingdom, MGC Diagnostics in the United States, U-Breath in Zhejiang, China, Wendi in Ningbo, Zhejiang, and Boya in Ningbo, China) were tested. RESULTS: A total of 75% (12/16) of the volume calibration syringes passed the pressure decay leak test, 69% (11/16) of the volume calibration syringes passed the volume accuracy and repeatability test, and 56% (9/16) passed both tests; there was no significant difference in the total passing of the new and old volume calibration syringe quality tests (P > 0.05). CONCLUSIONS: A standard validator device should be used for both leakage tests and volume accuracy and repeatability tests to ensure the reliability of volume calibration syringes. It is suggested that the quality verification of volume calibration syringes should be regularly conducted to ensure the accuracy of the pulmonary function tests.


Asunto(s)
Jeringas , Calibración , Humanos , Reproducibilidad de los Resultados , Pruebas de Función Respiratoria , Espirometría
15.
Small ; 18(23): e2201831, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35507778

RESUMEN

Poor light stability hinders the potential applications of perovskite optoelectronic devices. Recent experiments have demonstrated that the passivation surface via forming strong chemical bonds (SO4 -Pb, PO4 -Pb, Cl-Pb, O-Pb, and S-Pb) could effectively improve the light stability of perovskite solar cells. However, the underlying reasons are not clear. Herein, the elusive underlying mechanisms of light stability enhancement are explained in detail using first principles calculations. The small polaron model and self-trapped exciton model demonstrate that an iodine vacancy defect on the surface of perovskite could trap a free electron under light illumination, which leads to a significant rearrangement of the Pb-I lattice and creats a new chemical species, i.e., a Pb-Pb dimer bound in the typical perovskite of CH3 NH3 PbI3 . The Pb-Pb dimer distorts the Pb-I octahedral lattice and reduces the defect formation energy of the I atoms. The surface Pb site passivation can prevent the formation of the Pb-Pb dimer, thereby improving the light stability. In addition, the strong ionic bond could better stabilize the Pb site. The in-depth understanding of the light stability and the passivation mechanism in this study can promote the application of perovskite optoelectronic devices.

16.
ISME J ; 15(8): 2366-2378, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33649554

RESUMEN

In marine ecosystems, viruses exert control on the composition and metabolism of microbial communities, influencing overall biogeochemical cycling. Deep sea sediments associated with cold seeps are known to host taxonomically diverse microbial communities, but little is known about viruses infecting these microorganisms. Here, we probed metagenomes from seven geographically diverse cold seeps across global oceans to assess viral diversity, virus-host interaction, and virus-encoded auxiliary metabolic genes (AMGs). Gene-sharing network comparisons with viruses inhabiting other ecosystems reveal that cold seep sediments harbour considerable unexplored viral diversity. Most cold seep viruses display high degrees of endemism with seep fluid flux being one of the main drivers of viral community composition. In silico predictions linked 14.2% of the viruses to microbial host populations with many belonging to poorly understood candidate bacterial and archaeal phyla. Lysis was predicted to be a predominant viral lifestyle based on lineage-specific virus/host abundance ratios. Metabolic predictions of prokaryotic host genomes and viral AMGs suggest that viruses influence microbial hydrocarbon biodegradation at cold seeps, as well as other carbon, sulfur and nitrogen cycling via virus-induced mortality and/or metabolic augmentation. Overall, these findings reveal the global diversity and biogeography of cold seep viruses and indicate how viruses may manipulate seep microbial ecology and biogeochemistry.


Asunto(s)
Sedimentos Geológicos , Microbiota , Metano , Océanos y Mares , Filogenia , ARN Ribosómico 16S
17.
J Phys Condens Matter ; 32(44): 445004, 2020 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-32688354

RESUMEN

Interfacial electronic properties are greatly significant to study the photoelectric properties of semiconductor heterostructures. The novel heterostructures are constructed using perovskite 3D CsPbX3 (X = Cl, Br, I) and 2D PtSe2, and the structural and photoelectrical properties are studied by density functional theory. The band levels transform and interfacial charge transfer have serious differences at the interface of the CsPbX3-PtSe2 heterostructures. The CsPbCl3-PtSe2 and CsPbBr3-PtSe2 heterostructures show the type-I band arrangement, however, the CsPbI3-PtSe2 heterostructure demonstrate the type-II band arrangement. The difference in work function of the two semiconductors causes electrons to flow spontaneously at the interface. Moreover, the monolayer PtSe2 can broaden the absorption spectrum of the CsPbX3-PtSe2 heterostructures, that effectively enhance absorption capability of the heterostructures, especially the CsPbI3-PtSe2 heterostructure. These results demonstrate PtSe2 semiconductor materials can effectively improve the photoelectric performance of all-inorganic metal halide perovskite.

18.
J Phys Chem Lett ; 11(15): 6266-6272, 2020 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-32672042

RESUMEN

The stability of perovskites is an urgent problem to be solved before commercialization. An ultrathin PbF2 layer covering the perovskite can be an effective strategy to improve the stability of the perovskite greatly. The perovskite/PbF2 interface (XPbI3/PbF2, X = Cs and MA) is constructed, and the structural and chemical properties are studied by first-principles calculations. The results show that PbF2 has better structural stability than the perovskites and can stabilize the octahedral frame of perovskite in the perovskite/PbF2 interface. The PbF2 layer reconstructs the XPbI3 surface, resulting in the perovskite PbI interface transforming into a more stable XI interface in the perovskite/PbF2 interface. Meanwhile, the tiny stress compression in the perovskite/PbF2 interface can enhance the stability of perovskite. The large affinity of F atoms can adsorb free Pb atoms and suppress deleterious ion migration. In addition, the XPbI3/PbF2 interfaces have good dynamic stability at room temperature (300 K). Therefore, the PbF2 layer covering provides new ideas for the stability study of perovskites.

19.
Sci Rep ; 6: 22428, 2016 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-26932299

RESUMEN

We first report a simple nanoplasmonic sensor for both universal and slow-light sensing in a Fano resonance-based waveguide system. A theoretical model based on the coupling of resonant modes is provided for the inside physics mechanism, which is supported by the numerical FDTD results. The revealed evolution of the sensing property shows that the Fano asymmetric factor p plays an important role in adjusting the FOM of sensor, and a maximum of ~4800 is obtained when p = 1. Finally, the slow-light sensing in such nanoplasmonic sensor is also investigated. It is found that the contradiction between the sensing width with slow-light (SWS) and the relevant sensitivity can be resolved by tuning the Fano asymmetric factor p and the quality factor of the superradiant mode. The presented theoretical model and the pronounced features of this simple nanoplasmonic sensor, such as the tunable sensing and convenient integration, have significant applications in integrated plasmonic devices.

20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(6): 1656-61, 2016 Jun.
Artículo en Chino | MEDLINE | ID: mdl-30052366

RESUMEN

Ag nanowires (Ag NWs) are synthesized by polyol method under the conditions of different temperature of reaction solution, different addition amount and injection rate of polyvinylpyrrolidone (PVP). The structure and the process of lateral growth of Ag NWs were observed and analyzed by X-ray diffraction (XRD), ultraviolet-visible absorption spectrum (UV-VIS), scanning electron microscopy (SEM) and transmission electron microscope (TEM). It showed that the lateral growth of Ag NWs and longitudinal growth of Ag NWs occurrs at the same time by UV-VIS. And in the later stage of synthesis of Ag NWs, the peak in UV-VIS, which indicated the lateral growth of Ag NWs, red-shifted obviously from 384 nm to 388 nm. This rapid redshift implied that the diameters of Ag NWs increased quickly. In other words, rapid lateral growth of Ag NWs occurred in the later stage of synthesis of Ag NWs. According to the SEM of Ag NWs, in the early stage of the reaction (15~23 min), the diameter of Ag NWs increased by only 20 nm, but in the later stage of reaction (23~30 min), the diameter of Ag NWs increased by nearly 150 nm. The result of SEM observation is consistent with the analysis of UV-VIS. It was also found that the lateral growth of Ag NWs is related not only to the sizes of seeds but also to the thicknesses of the outer Ag layers. Tiny Ag particles with diameters of several nanometers adsorbed onto the side facets of Ag NWs and acted as adsorption points for Ag source. The lateral growth of Ag NWs was caused by the continuous multipoint adsorption of Ag source on the side of Ag NWs. Decreasing the temperature of the reaction solution (from 165 to 155 degree), reducing the injection rate (from 67 to 49 mL·h-1) and the addition amount of PVP in the later stage could inhibit the lateral growth of Ag NWs and increase the aspect ratios of Ag NWs remarkably. The diameters of Ag NWs decreased from 200 nm to 100 nm, but their lengths still maintained above 100 µm.

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