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1.
Arch Microbiol ; 206(7): 332, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38951206

RESUMO

A Gram-stain-negative, aerobic, rod-shaped and motile strain HL-JVS1T, was isolated from the gastric tract of a juvenile Pacific white shrimp. Molecular phylogenetic analysis based on 16S rRNA gene sequences of strain HL-JVS1T revealed its affiliation with the genus Pleionea, with close relatives including Pleionea mediterranea MOLA115T (97.5%) and Pleionea sediminis S1-5-21T (96.2%). The complete genome of strain HL-JVS1T consisted of a circular 4.4 Mb chromosome and two circular plasmids (6.6 and 35.0 kb) with a G + C content of 43.1%. The average nucleotide identity and digital DNA-DNA hybridization values between strain HL-JVS1T and the type strains of described Pleionea species were 69.7-70.4% and 18.3-18.6%, respectively. Strain HL-JVS1T grew at 10-40 °C (optimum, 30 °C) in the presence of 0.5 - 9.0% (w/v) sea salts (optimum, 2.0 - 2.5%), and at pH range of 5.5 - 10.0 (optimum, pH 6.5). The major fatty acids (> 10%) were summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl) (23.3%), iso-C16:0 (14.5%), iso-C11:0 3-OH (13.8%) and iso-C15:0 (11.0%). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid, two unidentified aminolipids, and two unidentified lipids. The respiratory quinone was ubiquinone-8. The comprehensive phylogenetic, phylogenomic, phenotypic and chemotaxonomic results showed that strain HL-JVS1T is distinct from other Pleionea species. Hence, we propose strain HL-JVS1T as a novel species belonging to the genus Pleionea, for which the name Pleionea litopenaei sp. nov. is proposed with HL-JVS1T (= KCCM 90514T = JCM 36490T) as the type strain.


Assuntos
Composição de Bases , DNA Bacteriano , Ácidos Graxos , Penaeidae , Filogenia , RNA Ribossômico 16S , Animais , RNA Ribossômico 16S/genética , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Hibridização de Ácido Nucleico , Análise de Sequência de DNA , Genoma Bacteriano , Planococáceas/genética , Planococáceas/isolamento & purificação , Planococáceas/classificação , Trato Gastrointestinal , Fosfolipídeos/análise
2.
Biotechnol Lett ; 46(2): 235-247, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38231384

RESUMO

PURPOSE: Dendritic cell (DC) is a spearhead responsible for immune response and surrounded by extracellular matrix in three-dimensional (3D) tissue. Nevertheless, conventional DC culture has relied on suspension or two-dimensional (2D) tissue culture plate (TCP)-based culture system. This culture condition often fails to recapitulate the physiological behavior of DC in real tissue. In this work, the effect of culture condition on DC physiology was explored with varying 3D hydrogel property (i.e., degradability, adhesion, and stiffness). In particular, DC differentiation and maturation in 3D were evaluated comparing the conventional TCP-based culture condition. METHOD: THP-1 cells were encapsulated in poly(ethylene glycol) (PEG) hydrogel via thiol-ene photocrosslinking with non-degradable or proteolytically degradable peptide crosslinker. Hydrogel stiffness was manipulated by controlling the concentration of crosslinker. The metabolic activities and cytotoxicity of the encapsulated cells were measured by resazurin and Live/Dead assays, respectively. Cell harvesting was conducted via enzymatic degradation using α-chymotrypsin, and differentiation and maturation of the liberated DCs were evaluated by quantitative polymerase chain reaction and flow cytometry. RESULTS: THP-1 cells well proliferated in the soft degradable hydrogel with a higher metabolic activity. However, the stiff matrix inhibited cell growth in 3D. The gene expression assay indicated that the 3D hydrogel condition was superior to 2D culture in terms of differentiation and maturation of DC. Interestingly, the stiffness of matrix was important factor in DC function. In the stiff hydrogel, the expression levels of differentiation and maturation markers were higher compared to the low stiffness hydrogel. The mature DCs caged in the hydrogel matrix were harvested after short enzymatic digestion of hydrogel and the liberated cells had over 90% viability. The flow cytometric result revealed that the proportion of CD80 + /CD86 + cells from the stiff hydrogel was relatively higher than cells either from 2D or soft hydrogel in 3D. CONCLUSION: The collected evidence indicated that the proteolytically degradable PEG hydrogel matrix promoted DC differentiation and maturation. In addition, the matrix stiffness control could manipulate the marker expressions of differentiation and maturation. Particularly, the mature DC was successfully collected from the hydrogel matrix. These results highlighted the PEG hydrogel-based DC culture might be a useful tool for potential DC-based immunotherapies.


Assuntos
Materiais Biocompatíveis , Hidrogéis , Humanos , Células THP-1 , Hidrogéis/química , Materiais Biocompatíveis/farmacologia , Polietilenoglicóis/química , Diferenciação Celular , Células Dendríticas
3.
Fish Shellfish Immunol ; 135: 108658, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36868538

RESUMO

The purpose of this study is to investigate the effect of inorganic mercury (Hg) on fish. Inorganic Hg is less toxic than organic Hg, but it is used more in human daily life, such as manufacturing Hg batteries and fluorescent lamps. For this reason, inorganic Hg was used in this study. Starry flounder, Platichthys stellatus (mean weight 43.9 ± 4.4 g; mean length 14.2 ± 0.4 cm) were exposed for 4 weeks to the different levels of dietary inorganic Hg at concentrations of 0, 4, 8, 12 and 16 mg Hg/kg, and depuration was performed for 2 weeks after exposure. Bioaccumulation of Hg in the tissues was observed to increase significantly, in following order: intestine > head kidney > liver > gills > muscle. Antioxidant responses (superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and glutathione (GSH)) were significantly increased. Immune responses (lysozyme and phagocytosis activity) were substantially decreased. The results of this study suggest that dietary inorganic Hg induces bioaccumulation in specific tissues, increases antioxidant responses and decreases immune responses. After the depuration period for 2 weeks, it was effective to alleviate bioaccumulation in tissues. However, antioxidant and immune responses were limited to be attenuated for recovery.


Assuntos
Linguado , Mercúrio , Poluentes Químicos da Água , Humanos , Animais , Antioxidantes , Mercúrio/toxicidade , Glutationa , Fagocitose , Poluentes Químicos da Água/toxicidade
4.
Ecotoxicol Environ Saf ; 265: 115469, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37742571

RESUMO

This study aimed to determine the toxicity standard and potential risks and effects of polyamide (PA) exposure on neurotoxicity, stress indicators, and immune responses in juvenile crucian carp Carassius carassius. Numerous microplastics (MPs) exists within aquatic environments, leading to diverse detrimental impacts on aquatic organisms. The C. carassius (mean weight, 23.7 ± 1.6 g; mean length, 13.9 ± 1.4 cm) were exposed to PA concentrations of 0, 4, 8, 16, 32 and 64 mg/L for 2 weeks. Among the neurotransmitters, the acetylcholinesterase (AChE) activity in the liver, gill, and intestine of C. carassius was significantly inhibited by PA exposure. Stress indicators such as cortisol and heat shock protein 70 (HSP70) in the liver, gill, and intestine of C. carassius were significantly increased, while immune responses to lysozyme and immunoglobulin M (IgM) were significantly decreased. Our study demonstrates the toxic effects of MP exposure on crucian carp's neurotoxicity, stress indicators, and immune responses.

5.
Sensors (Basel) ; 23(3)2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36772630

RESUMO

Occupational health and safety hazards associated with confined places are mainly caused by exposure to toxic gases and oxygen deficiency. Lack of awareness, inappropriate monitoring, and improper evacuation methods can lead to worker fatalities. Although previous studies have attempted to develop systems to solve this issue, limited research is available on their application in confined places. In this study, a real-time helmet-mounted system was developed to monitor major toxic gases (methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon monoxide (CO)), oxygen, temperature, and humidity. Workers outside and inside confined spaces receive alerts every second to immediately initiate the rescue operation in the event of a hazard. The test results of a confined environment (wastewater treatment unit) highlighted that concentrations of CH4 and H2S were predominant (13 ppm). Compared to normal atmosphere, CH4 concentration was 122- and 130-fold higher in the landfill and digestion tanks, respectively, while H2S was 36- and 19-fold higher in the primary and secondary clarifiers, respectively. The oxygen content (18.2%) and humidity (33%) were below the minimum required limits. This study will benefit future research to target appropriate toxic gas monitoring and alert workers by studying the existing issues and associated factors in confined places.


Assuntos
Dispositivos de Proteção da Cabeça , Sulfeto de Hidrogênio , Humanos , Gases/toxicidade , Monóxido de Carbono , Oxigênio
6.
J Environ Manage ; 342: 118237, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37267764

RESUMO

This review describes the applicability of biofloc technology (BFT) to future aquaculture technologies. BFT is considered an innovative alternative for solving the problems of traditional aquaculture (for example, environmental pollution, high maintenance costs, and low productivity). Extensive research is being conducted to apply BFT to breed and raise many aquatic animal species. In BFT, maintaining an appropriate C:N ratio by adding a carbon source promotes the growth of microorganisms in water and maintains the aquaculture water quality through microbial processes such as nitrification. For the efficient use and sustainability of BFT, various factors such as total suspended solids, water turbidity, temperature, dissolved oxygen, pH, and salinity, stocking density, and light should be considered. The application of the transformative fourth industrial revolution technologies, Information and Communications Technology (ICT) and Internet of Things (IoT), to aquaculture can reduce the risk factors and manual interventions in aquaculture through automation and intelligence. The combination of ICT/IoT with BFT can enable real-time monitoring of the necessary elements of BFT farming using various sensors, which is expected to increase productivity by ensuring the growth and health of the organisms being reared.


Assuntos
Aquicultura , Nitrificação , Animais , Tecnologia , Qualidade da Água , Fatores de Risco
7.
Microb Pathog ; 166: 105545, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35452787

RESUMO

Shrimp aquaculture industry has steadily increased with demand and development of aquaculture technology. In recent years, frequent diseases have become a major risk factor for shrimp aquaculture, such as a drastically reduced the production of shrimp and causing national economic loss. Among them, shrimp bacterial diseases such as hepatopancreatic necrosis disease (AHPND) and necrotizing hepatopancreatitis (NHP-B) and parasitic disease such as Aphanomyces astaci (crayfish plague) are emerging and evolving into new types. OIE (World Organization for Animal Health) regularly updates information on diseases in the Aquatic Code and Aquatic Manual, but in-depth information on the shrimp diseases are lacking. Therefore, the purpose of this review is to provide information necessary for the response and prevention of shrimp diseases by understanding the characteristics and diagnosis of shrimp diseases designated by OIE.


Assuntos
Doenças Parasitárias , Penaeidae , Animais , Aquicultura , Necrose , Penaeidae/microbiologia , Alimentos Marinhos
8.
Nano Lett ; 21(13): 5500-5507, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-33913722

RESUMO

Sharks, marine creatures that swim fast and have an antifouling ability, possess dermal denticle structures of micrometer-size. Because the riblet geometries on the denticles reduce the shear stress by inducing the slip of fluid parallel to the stream-wise direction, shark skin has the distinguished features of low drag and antifouling. Although much attention has been given to low-drag surfaces inspired from shark skin, it remains an important challenge to accurately mimic denticle structures in the micrometer scale and to finely control their structural features. This paper presents a novel method to create shark skin-mimetic denticle structures for low drag by exploiting a photoreconfigurable azopolymer. The light-designed denticle structure exhibits superior hydrophobicity and an antifouling effect as sharks do. This work suggests that our novel photoreconfiguration technology, mimicking shark skin and systematically manipulating various structural parameters, can be used in a reliable manner for diverse applications requiring low-drag surfaces.


Assuntos
Tubarões , Animais , Biomimética , Interações Hidrofóbicas e Hidrofílicas , Pele
9.
Angew Chem Int Ed Engl ; 59(28): 11491-11500, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32233096

RESUMO

Amyloid-ß (Aß) oligomers are implicated in Alzheimer disease (AD). However, their unstable nature and heterogeneous state disrupts elucidation of their explicit role in AD progression, impeding the development of tools targeting soluble Aß oligomers. Herein parallel and anti-parallel variants of Aß(1-40) dimers were designed and synthesized, and their pathogenic properties in AD models characterized. Anti-parallel dimers induced cognitive impairments with increased amyloidogenesis and cytotoxicity, and this dimer was then used in a screening platform. Through screening, two FDA-approved drugs, Oxytetracycline and Sunitinib, were identified to dissociate Aß oligomers and plaques to monomers in 5XFAD transgenic mice. In addition, fluorescent Astrophloxine was shown to detect aggregated Aß in brain tissue and cerebrospinal fluid samples of AD mice. This screening platform provides a stable and homogeneous environment for observing Aß interactions with dimer-specific molecules.


Assuntos
Peptídeos beta-Amiloides/química , Amiloide/química , Memória/efeitos dos fármacos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Amiloide/farmacologia , Animais , Dimerização , Descoberta de Drogas , Feminino , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Placa Amiloide/metabolismo , Placa Amiloide/patologia
10.
J Nanosci Nanotechnol ; 19(3): 1350-1359, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469187

RESUMO

Graphene/Co(OH)2 nanowire composite films were successfully synthesized using a simple three-step treatment, and the effect of the Co(OH)2 nanowire content on the electrochemical properties of the composite films was studied in this study. One-dimensional Co(OH)2 nanowires were homogeneously embedded and dispersed between the prepared graphene papers, forming a layered graphene/Co(OH)2 nanowire hybrid structure. These composite films exhibited better electrochemical properties than the previously reported graphene composites with carbon spheres such as graphene/CNT composites. These graphene composites were fabricated using the same method we used in this study but without the addition of Co(OH)2 nanowires. The addition of a small amount of Co(OH)2 to reduced graphene oxide (rGO) (RGO:Co(OH)2=5:1) yielded thick paper-like rGO/Co(OH)2 sandwiches, which showed an excellent specific capacitance of 1032.57 Fg-1 at a scan rate of 5 mVs-1. These results indicate the potential of these composites for the development of highly capacitive energy storage devices for practical applications.

11.
J Nanosci Nanotechnol ; 19(3): 1574-1579, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469225

RESUMO

We investigated the change in the cell efficiency resulting from electron beam accelerated irradiation to understand the possibility of using silicon solar cells with nano-surfaces for satellites. The Si solar cells were made of 6″ micro-textured p-type Si wafers. The Si solar cells were fabricated using a standard cell fabrication process, including POCl3 diffusion, anti-reflection coating layer deposition, and metal contact and co-firing heat treatment. After manufacturing the cell, we irradiated the cell with a low-energy electron beam to determine its effect. We analyzed the changes in the cell resulting from the irradiation with the electron beam by evaluating the photo-reflectance, transmission electron microscopy, electroluminescence and current-voltage curve.

12.
Appl Opt ; 58(11): 2913-2919, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-31044898

RESUMO

Recently, the analytical expressions for the atmospheric-induced frequency spreads of optical waves propagating in anisotropic atmosphere turbulence were derived in our work. Meanwhile, more research also draws on the theoretical survey of maritime atmospheric turbulence. In this paper, the new expressions for the temporal frequency spreads of plane and spherical waves propagating in anisotropic maritime atmospheric turbulence are derived. Based on the new expressions obtained, the combined effects of the power law exponent, turbulence strength, turbulence scales, and the anisotropic parameter are evaluated. The analytical simulation results show that the turbulence strength and the anisotropic parameter significantly affect the curves of the temporal frequency spread. Furthermore, it is important to note that the temporal frequency spreads of optical waves in the anisotropic maritime turbulence and the terrestrial turbulence become almost identical as the value of the anisotropic parameter goes beyond five.

13.
Small ; 14(11): e1703250, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29369496

RESUMO

Directional photofluidization of azobenzene materials has provided unprecedented opportunities for the structural reconfiguration of circular holes, line gaps, ellipsoidal holes, and nanofunnel-shaped micro/nanoarchitectures. However, all the reconfigured structures have a parabolic or round wall due to the tendency of the photofluidized azobenezene materials to minimize the surface area, which limits their use as a reconfigurable etch-mask for the lithography process. In this work, a simple method is presented that can change the round walls of azopolymer architectures into rectangular walls, which is named rectangularization. By irradiating far-field light on reconfigured azopolymer in a conformal contact with a flat polydimethylsiloxane (PDMS) film, the round wall transforms to a rectangular one because the azopolymer adheres along the PDMS surface while being photofluidized. As a result, the rectangularization process creates a variety of structural features and sizes ranging from a few micrometers to 150 nm having a rectangular wall. By exploiting the rectangularization process, the concept of a photo-reconfigurable etch mask is achieved, which transfers the mask patterns to a silicon pattern with a high structural fidelity and imparts a considerable flexibility to the lithography process.

14.
J Nanosci Nanotechnol ; 18(9): 6442-6446, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29677811

RESUMO

The back sheet is one of the most important materials in photovoltaic (PV) modules. It plays an important role in protecting the solar cell from the environment by preventing moisture penetration. In the back sheet, the outermost layer is composed of a polyester (PET) film to protect the PV module from moisture, and the opposite layer is composed of a TiO2 + PE material. Nowadays, PV modules are installed in the desert. Therefore, methods to improve the power generation efficiency of PV modules need to be investigated as the efficiency is affected by temperature resulting from the heat radiation effect. Using a back sheet with a high thermal conductivity, the module output efficiency can be increased as heat is efficiently dissipated. In this study, a thermally conductive film was fabricated by mixing a reference film (TiO2 + PE) and a non-metallic material, MgO, with high thermal conductivity. UV irradiation tests of the film were conducted. The thermally conductive film (TiO2 + PE + MgO) showed higher conductivity than a reference film. No visible cracks and low yellowing degree were found in thermally conductive film, confirming its excellent UV durability characteristics. The sample film was bonded to a PET layer, and a back sheet was fabricated. The yellowing of the back sheet was also analyzed after UV irradiation. In addition, mini modules with four solar cell were fabricated using the developed back sheet, and a comparative outdoor test was conducted. The results showed that power generation improved by 1.38%.

16.
Phys Chem Chem Phys ; 18(29): 19696-704, 2016 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-27381559

RESUMO

Recently, attention has been focused on the synthesis and application of nanocomposites for supercapacitors, which can have superior electrochemical performance than single structured materials. Here, we report a carbon-coated TiO2/Co3O4 ternary hybrid nanocomposite (TiO2@C/Co) electrode for supercapacitors. A carbon layer was directly introduced onto the TiO2 surface via thermal vapor deposition. The carbon layer provides anchoring sites for the deposition of Co3O4, which was introduced onto the carbon-coated TiO2 surface by hydrazine and the thermal oxidation method. The TiO2@C/Co electrode exhibits much higher charge storage capacity relative to pristine TiO2, carbon-coated TiO2, and pristine Co3O4, showing a specific capacitance of 392.4 F g(-1) at a scan rate of 5 mV s(-1) with 76.2% rate performance from 5 to 500 mV s(-1) in 1 M KOH aqueous solution electrolyte. This outstanding electrochemical performance can be attributed to the high conductivity and high pseudo-capacitive contributions of the nanoscale particles. To evaluate the capacitive performance of a supercapacitor device employing the TiO2@C/Co electrode, we have successfully assembled TiO2@C/Co//activated carbon (AC) asymmetric supercapacitors. The optimized TiO2@C/Co//AC supercapacitor could be cycled reversibly in the voltage range from 0 to 1.5 V, and it exhibits a specific capacitance of 59.35 F g(-1) at a scan rate of 5 mV s(-1) with a specific capacitance loss of 15.4% after 5000 charge-discharge cycles. These encouraging results show great potential in terms of developing high-capacitive energy storage devices for practical applications.

17.
ScientificWorldJournal ; 2014: 975054, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24707224

RESUMO

Improving the energy efficiency in wireless sensor networks (WSN) has attracted considerable attention nowadays. The multiple-input multiple-output (MIMO) technique has been proved as a good candidate for improving the energy efficiency, but it may not be feasible in WSN which is due to the size limitation of the sensor node. As a solution, the cooperative multiple-input multiple-output (CMIMO) technique overcomes this constraint and shows a dramatically good performance. In this paper, a new CMIMO scheme based on the spatial modulation (SM) technique named CMIMO-SM is proposed for energy-efficiency improvement. We first establish the system model of CMIMO-SM. Based on this model, the transmission approach is introduced graphically. In order to evaluate the performance of the proposed scheme, a detailed analysis in terms of energy consumption per bit of the proposed scheme compared with the conventional CMIMO is presented. Later, under the guide of this new scheme we extend our proposed CMIMO-SM to a multihop clustered WSN for further achieving energy efficiency by finding an optimal hop-length. Equidistant hop as the traditional scheme will be compared in this paper. Results from the simulations and numerical experiments indicate that by the use of the proposed scheme, significant savings in terms of total energy consumption can be achieved. Combining the proposed scheme with monitoring sensor node will provide a good performance in arbitrary deployed WSN such as forest fire detection system.


Assuntos
Redes de Comunicação de Computadores , Modelos Teóricos , Tecnologia sem Fio , Algoritmos
18.
Heliyon ; 10(7): e27765, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38560156

RESUMO

Air pollution caused by the construction industry in the form of particulate matter (PM) has increased to an alarming level. The effects on the health of construction workers are found to be hazardous despite the current advancement in construction methods and practices. In particular, the efficiency of existing control measures for reducing PM from various construction activities has not been improved to the desired level. This study investigated the factors that influence the efficiency of a sprinkler system-based control measure when water spraying and dust suppressant solutions are used. The real-time PM exposure was measured during hollow-block cutting activity using Alphanese OPC-N3 sensors in dust chamber. The dust suppressant suppresses dust particles by initially forming a solidified film on the particle surface, and the high cohesion of this film enhances the suppression rate by promoting dust particle coagulation. It was observed that when using a dust suppressant, the PM concentration at 100 bar exceeded concentrations at other pressures, resulting in increased efficacy in reducing PM10. Additionally, water spraying at 115 bar was determined to be the optimal control measure for achieving a significant percentage of PM reduction in a shorter period. These findings can be highly beneficial if the water sprinkler system can be modified into a smart mobility-based sprinkler system either ground-based or drone-based at construction sites in improving PM reduction efficiency particularly on high PM emitting activities.

19.
ACS Appl Mater Interfaces ; 16(2): 2457-2466, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38166386

RESUMO

Recent studies have focused on exploring the potential of resistive random-access memory (ReRAM) utilizing halide perovskites as novel data storage devices. This interest stems from its notable attributes, including a high ON/OFF ratio, low operating voltages, and exceptional mechanical properties. Nevertheless, there have been reports indicating that memory systems utilizing halide perovskites encounter certain obstacles pertaining to their stability and dependability, mostly assessed through endurance and retention time. Moreover, the presence of these problems can potentially restrict their practical applicability. This study explores a resistive switching memory device utilizing MAPbBr3 perovskite, which demonstrates bipolar switching characteristics. The device fabrication procedure involves a low-temperature, all-solution process. For the purpose of enhancing the device's reliability, the utilization of TPBI(2,2',2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) as an electron transfer material on the MAPbBr3 switching layer was implemented for the first time. The formation and rupture of Ag filaments in the MAPbBr3 perovskite switching layer are attributed to reduction-oxidation reactions. The TPBI is involved in the regulation of filaments during the SET and RESET processes. Hence, it can be shown that the MAPbBr3 device incorporating TPBI exhibited about 1000 endurance cycles when subjected to continuous voltage pulses. Moreover, the device consistently maintained ON/OFF ratios above 107. In contrast, the original MAPbBr3 device without TPBI demonstrated a significantly lower endurance with only 90 cycles observed. In addition, the MAPbBr3 device integrated with TPBI exhibited a retention time exceeding 3 × 103 s. The findings of this research provide compelling evidence to support the notion that electron transfer materials have promise for the development of halide perovskite memory systems owing to their favorable attributes of dependability and stability.

20.
J Nanosci Nanotechnol ; 13(9): 6189-95, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24205626

RESUMO

We investigated the nanocatalytic growth of Si nanowires on the microtextured surface of crystalline Si solar cell. 3C-SiC nanoparticles have been used as the base for formation of Ni silicate layer in a catalytic reaction with the Si melt under H2 atmosphere at an annealing temperature of 1100 degrees C. The 10-nm thick Ni film was deposited after the SiC nanoparticles were coated on the microtextured surface of the Si solar cell by electron-beam evaporation. SiC nanoparticles form a eutectic alloy surface of Ni silicate and provide the base for Si supersaturation as well as the Ni-Si alloy layer on Si substrate surface. This bottom reaction mode for the solid-liquid-solid growth mechanism using a SiC nanoparticle base provides more stable growth of nanowires than the top reaction mode growth mechanism in the absence of SiC nanoparticles. Thermally excited Ni nanoparticle forms the eutectic alloy and provides collectively excited electrons at the alloy surface, which reduces the activation energy of the nanocatalytic reaction for formation of nanowires.

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