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1.
Adv Sci (Weinh) ; 10(12): e2207210, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36775851

RESUMO

Periodically patterned surfaces can cause special surface properties and are employed as functional building blocks in many devices, yet remaining challenges in fabrication. Advancements in fabricating structured polymer surfaces for obtaining periodic patterns are accomplished by adopting "top-down" strategies based on self-assembly or physico-chemical growth of atoms, molecules, or particles or "bottom-up" strategies ranging from traditional micromolding (embossing) or micro/nanoimprinting to novel laser-induced periodic surface structure, soft lithography, or direct laser interference patterning among others. Thus, technological advances directly promote higher resolution capabilities. Contrasted with the above techniques requiring highly sophisticated tools, surface instabilities taking advantage of the intrinsic properties of polymers induce surface wrinkling in order to fabricate periodically oriented wrinkled patterns. Such abundant and elaborate patterns are obtained as a result of self-organizing processes that are rather difficult if not impossible to fabricate through conventional patterning techniques. Focusing on oriented wrinkles, this review thoroughly describes the formation mechanisms and fabrication approaches for oriented wrinkles, as well as their fine-tuning in the wavelength, amplitude, and orientation control. Finally, the major applications in which oriented wrinkled interfaces are already in use or may be prospective in the near future are overviewed.

2.
Langmuir ; 38(27): 8312-8323, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35767278

RESUMO

Water removal from water-in-oil emulsions with superhydrophobic microporous membranes is an important industrial process, where the interface property between the membrane and feed becomes critical. Here, superhydrophobic isotactic polypropylene (iPP) microporous membranes with the "lotus effect" and "rose-petal effect" were prepared via utilizing micromolding phase separation, where the former surface exhibited a water contact angle of 153° and a sliding angle of 3.2°, while the latter surface exhibited a water contact angle of 151° and adhesive characteristics. Surface topography and wettability analysis revealed that surface hydrophobicity and water adhesion could be improved by reducing the periodic distance and diameter and increasing the height of the micron-scale structure. When treating both water-in-oil emulsions and water-in-oil emulsions containing BSA pollutants, the iPP membrane with the "lotus effect" was superior to that with the "rose-petal effect" in terms of oil permeate flux, separation efficiency, anti-fouling ability, and recyclability (20 cycles). To explain this phenomenon, a "slippery" mechanism was introduced that correlated the sliding angle to the slippery surface of the iPP membrane with the "lotus effect" and its anti-water adhesion property. This work proposed a theoretical platform for investigating the effect of water adhesion on superhydrophobic membranes in terms of oil-water separation efficiency and anti-fouling ability, thereby providing a definite basis for preparing superhydrophobic membranes with efficient separation and fouling resistance capabilities.


Assuntos
Incrustação Biológica , Membranas Artificiais , Incrustação Biológica/prevenção & controle , Emulsões/química , Interações Hidrofóbicas e Hidrofílicas , Molhabilidade
3.
Front Neurorobot ; 15: 660304, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33967732

RESUMO

With the rapid development of social network, intelligent terminal and automatic positioning technology, location-based social network (LBSN) service has become an important and valuable application. Point of interest (POI) recommendation is an important content in LBSN, which aims to recommend new locations of interest for users. It can not only alleviate the information overload problem faced by users in the era of big data, improve user experience, but also help merchants quickly find target users and achieve accurate marketing. Most of the works are based on users' check-in history and social network data to model users' personalized preferences for interest points, and recommend interest points through collaborative filtering and other recommendation technologies. However, in the check-in history, the multi-source heterogeneous information (including the position, category, popularity, social, reviews) describes user activity from different aspects which hides people's life style and personal preference. However, the above methods do not fully consider these factors' combined action. Considering the data privacy, it is difficult for individuals to share data with others with similar preferences. In this paper, we propose a privacy protection point of interest recommendation algorithm based on multi-exploring locality sensitive hashing (LSH). This algorithm studies the POI recommendation problem under distributed system. This paper introduces a multi-exploring method to improve the LSH algorithm. On the one hand, it reduces the number of hash tables to decrease the memory overhead; On the other hand, the retrieval range on each hash table is increased to reduce the time retrieval overhead. Meanwhile, the retrieval quality is similar to the original algorithm. The proposed method uses modified LSH and homomorphic encryption technology to assist POI recommendation which can ensure the accuracy, privacy and efficiency of the recommendation algorithm, and it verifies feasibility through experiments on real data sets. In terms of root mean square error (RMSE), mean absolute error (MAE) and running time, the proposed method has a competitive advantage.

4.
Toxicon ; 127: 85-89, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-27889603

RESUMO

The entomopathogenic nematode Heterorhabditis spp. is considered a promising agent in the biocontrol of injurious insects of agriculture. However, different symbiotic bacteria associated with the nematode usually have different specificity and virulence toward their own host. In this study, two symbiotic bacteria, LY2W and NK, were isolated from the intestinal canals of two entomopathogenic nematode Heterorhabditis megidis 90 (PDSj1 and PDSj2) from Galleria mellonela, separately. To determine their species classification, we carried out some investigations on morphology, culture, biochemistry, especially 16S rDNA sequence analyses. As a result, both of them belong to Enterobacter spp., showing the closest relatedness with Enterobacter gergoviae (LY2W) and Enterobacter cloacae (NK), respectively. Moreover, the toxicity to Galleria mellonella was examined using both the metabolites and washed cells (primary and secondary) of these two strains. The results indicated both metabolites and cells of the primary-type bacteria could cause high mortalities (up to 97%) to Galleria mellonella, while those of the primary-type bacteria only killed 20%. These findings would provide new symbiotic bacteria and further references for biological control of the agricultural pest.


Assuntos
Enterobacter/isolamento & purificação , Mariposas/microbiologia , Mariposas/parasitologia , Nematoides/microbiologia , Animais , DNA Bacteriano/genética , DNA Ribossômico/genética , Enterobacter/classificação , Enterobacter/genética , Larva/microbiologia , Larva/parasitologia , Filogenia , Simbiose
5.
Appl Biochem Biotechnol ; 177(2): 567-76, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26194712

RESUMO

In the biocontrol of harmful algal blooms, there has been considerable interest about the role of algicidal bacteria in algicidal activity. In this experiment, two novel algicidal bacteria (strains NP23 and AM11) against Chlorella pyrenoidosa were isolated from the Baiguishan reservoir in China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains NP23 and AM11 belonged to Enterobacter cloacae and Gibberella moniliformis, respectively. To further understand the algicidal activities, five parameters including the chlorophyll a content, cell survival rate, superoxide dismutase (SOD) peroxide dismutase (POD), and catalase (CAT) were tested in the C. pyrenoidosa cells after inoculation with the algicidal bacteria Enterobacter cloacae NP23 and Gibberella moniliformis AM11. As a result, the growth of the treated C. pyrenoidosa was significantly restrained with a great decline of chlorophyll a content. Meanwhile, three antioxidase activities of the treated C. pyrenoidosa were initially stimulated from day 1 to day 3 but then dramatically inhibited at low level. These results induced that the oxidative imbalance (i.e., inhibition of antioxidase activities) caused by algicidal bacteria could be the killing agent of the C. pyrenoidosa cells.


Assuntos
Antioxidantes/metabolismo , Bactérias/isolamento & purificação , Chlorella/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Clorofila A , Viabilidade Microbiana , Peroxidase/metabolismo , Superóxido Dismutase/metabolismo
6.
Can J Microbiol ; 60(9): 593-7, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25188453

RESUMO

To control algal bloom caused by nutrient pollution, a wild-type algae-lysing bacterium was isolated from the Baiguishan reservoir in Henan province of China and identified as Enterobacter sp. strain NP23. Algal culture medium was optimized by applying a Placket-Burman design to obtain a high cell concentration of NP23. Three minerals (i.e., 0.6% KNO3, 0.001% MnSO4·H2O, and 0.3% K2HPO4) were found to be independent factors critical for obtaining the highest cell concentration of 10(13) CFU/mL, which was 10(4) times that of the control. In the algae-lysing experiment, the strain exhibited a high lysis rate for the 4 algae test species, namely, Chlorella vulgari, Scenedesmus, Microcystis wesenbergii, and Chlorella pyrenoidosa. Acute toxicity and mutagenicity tests showed that the bacterium NP23 had no toxic and mutagenic effects on fish, even in large doses such as 10(7) or 10(9) CFU/mL. Thus, Enterobacter sp. strain NP23 has strong potential application in the microbial algae-lysing project.


Assuntos
Carpas/genética , Meios de Cultura/química , Enterobacter/fisiologia , Animais , Agentes de Controle Biológico , Carpas/microbiologia , China , Chlorella/metabolismo , Clorofila/química , Clorofila A , Enterobacter/isolamento & purificação , Eutrofização , Microcystis/metabolismo , Testes para Micronúcleos , Mutagênese , Microbiologia da Água
7.
Int. j. morphol ; 30(4): 1389-1394, dic. 2012. ilus
Artigo em Inglês | LILACS | ID: lil-670154

RESUMO

In order to further studying the relationship between the gastrointestinal endocrine cells and the hibernation of Chinese fire-bellied newt, histological techniques were used in this study to explore the distributed density and morphology of argentaffine cells in the digestive tract during hibernation and non-hibernation. The argentaffine cells could be observed throughout the digestive tract of Chinese fire-bellied newt during hibernation and non-hibernation and mainly distributed in the acinar epithelial cells, epithelial cells and intrinsic membrane. They had appeared in the shape of goblet, pyramid, ellipse, round, cone-shaped, spindle-shaped. The cytoplasm contains secretory granules at the basal regions with spherical nuclei in the basal regions. Most of them had processes in different directions, suggesting that the argentaffine cells have combined the function of endocrine and exocrine. The distribution density curves of argentaffine cells were generally wavelike during the two periods. It was highest in the body of stomach in hibernation, while in non-hibernation it was highest in the pyloric. Totally the density of argentaffine cells was higher in hibernation period than that in non-hibernation period. The results showed that the activity of the digestive tract was expectedly weakened during the hibernation, but the function of endocrine was actually strengthened.


Con el fin de promover el estudio de la relación entre las células endocrinas gastrointestinales y la hibernación del tritón vientre de fuego chino, fueron utilizados técnicas histológicas para explorar la densidad de distribuición y la morfología de las células argentafines en el tracto digestivo durante la hibernación y la no hibernación. Las células argentafines pudieron ser observadas en todo el tracto digestivo de tritón vientre de fuego chino durante la hibernación y no hibernación, y se distribuyeron principalmente en las células epiteliales acinares, células epiteliales y la membrana intrínseca. Aparecieron de forma caliciforme, piramidal, elíptica, redonda, cónica y de huso. El citoplasma contenía gránulos de secreción en las regiones basales con núcleos esféricos en esa región. La mayoría de ellos tenía procesos en diferentes direcciones, lo que sugiere que las células argentafines combinaron la función del sistema endocrino y exocrino. Las curvas de densidad de distribución de las células argentafines fueron generalmente ondulante durante los dos períodos. Esta fue más alta en el cuerpo del estómago en estado de hibernación, mientras que en la no hibernación fue mayor en el píloro. En total, la densidad de las células argentafines era mayor en el periodo de hibernación. Los resultados mostraron que la actividad del tracto digestivo se debilitó, como era de esperar, durante la hibernación, pero la función del sistema endocrino se fortaleció.


Assuntos
Animais , Salamandridae , Trato Gastrointestinal/citologia , Células Enterocromafins , Hibernação
8.
Zhonghua Gan Zang Bing Za Zhi ; 14(7): 521-4, 2006 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-16867275

RESUMO

OBJECTIVE: To develop a RNAi approach that specifically targets the HCV IRES sequence by vector-expressed short hairpin RNA (shRNA) in vitro, and to assess the inhibitory effect of the shRNA on reporter gene expression. METHODS: Eukaryotic expressing plasmids, pIRES-GFP and p5' UTR-Luc containing GFP or luciferase gene controlled by HCV IRES were cotransfected into HepG2 cells with either a RNAi plasmid pshRNA-HCV or a control plasmid pTZU6+1. At 24, 48, 72 hours post transfection, the fluorescence in the transfected cells was studied using fluorescence microscopy. The levels of GFP RNA were determined using RT-PCR and those of protein were determined using Western blot. The activities of luciferase were assayed using a dual luciferase assay system. RESULTS: The introduction of RNAi plasmid efficiently and specifically down-regulated the expression of the reporter gene. RT-PCR showed that the RNAs of GFP gene were distinctly reduced (about 60%) when the pIRES-GFP was cotransfected with pshRNA-HCV, whereas the control vector did not exhibit inhibitory effect on the mRNA level, according to Western blot assay. The luciferase activity also decreased by 60%-70% in comparison to the control plasmid. CONCLUSION: Our results demonstrate that the shRNA targeting HCV IRES shows a strong inhibitive effect on the expression of the reporter gene controlled by this sequence, suggesting that RNAi-based anti-HCV strategy may represent a potential approach in the therapy of HCV infection.


Assuntos
Hepacivirus/genética , Interferência de RNA , RNA Mensageiro/genética , Ribossomos/metabolismo , Regulação da Expressão Gênica , Genes Reporter , Terapia Genética , Vetores Genéticos , Células Hep G2 , Hepatite C/terapia , Humanos , Ribossomos/genética , Transfecção
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