Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 120
Filtrar
1.
Mol Med Rep ; 23(4): 1, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33537828

RESUMO

As a chronic degenerative joint disease, the characteristics of osteoarthritis (OA) are degeneration of articular cartilage, subchondral bone sclerosis and bone hyperplasia. It has been reported that microRNA (miR)­186­5p serves a key role in the development of various tumors, such as osteosarcoma, non­small­cell lung cancer cells, glioma and colorectal cancer. The present study aimed to investigate the effect of miR­186­5p in OA. Different concentrations of IL­1ß were used to treat the human chondrocyte cell line CHON­001 to simulate inflammation, and CHON­001 cell injury was assessed by detecting cell viability, apoptosis, caspase-3 activity and the levels of TNF­α, IL­8 and IL­6. Subsequently, reverse transcription­quantitative PCR was performed to measure miR­186­5p expression. The results demonstrated that following IL­1ß treatment, CHON­001 cell viability was suppressed, apoptosis was promoted, the caspase-3 activity was significantly enhanced and the release of TNF­α, IL­8 and IL­6 was increased. In addition, IL­1ß treatment significantly upregulated miR­186­5p expression in CHON­001 cells. It was also identified that MAPK1 was a target gene of miR­186­5p, and was negatively regulated by miR­186­5p. miR­186 inhibitor and MAPK1­small interfering RNA (siRNA) were transfected into CHON­001 cells to investigate the effect of miR­186­5p on CHON­001 cell injury induced by IL­1ß. The results demonstrated that miR­186 inhibitor suppressed the effects of IL­1ß on CHON­001 cells, and these effects were reversed by MAPK1­siRNA. In conclusion, the present results indicated that miR­186­5p could attenuate IL­1ß­induced chondrocyte inflammation damage by increasing MAPK1 expression, suggesting that miR­186­5p may be used as a potential therapeutic target for OA.

2.
Planta ; 253(1): 8, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33387047

RESUMO

MAIN CONCLUSION: The molecular mechanism underlying white petal color in Brassica napus was revealed by transcriptomic and metabolomic analyses. Rapeseed (Brassica napus L.) is one of the most important oilseed crops worldwide, but the mechanisms underlying flower color in this crop are known less. Here, we performed metabolomic and transcriptomic analyses of the yellow-flowered rapeseed cultivar 'Zhongshuang 11' (ZS11) and the white-flowered inbred line 'White Petal' (WP). The total carotenoid contents were 1.778-fold and 1.969-fold higher in ZS11 vs. WP petals at stages S2 and S4, respectively. Our findings suggest that white petal color in WP flowers is primarily due to decreased lutein and zeaxanthin contents. Transcriptome analysis revealed 10,116 differentially expressed genes with a fourfold or greater change in expression (P-value less than 0.001) in WP vs. ZS11 petals, including 1,209 genes that were differentially expressed at four different stages and 20 genes in the carotenoid metabolism pathway. BnNCED4b, encoding a protein involved in carotenoid degradation, was expressed at abnormally high levels in WP petals, suggesting it might play a key role in white petal formation. The results of qRT-PCR were consistent with the transcriptome data. The results of this study provide important insights into the molecular mechanisms of the carotenoid metabolic pathway in rapeseed petals, and the candidate genes identified in this study provide a resource for the creation of new B. napus germplasms with different petal colors.

3.
Bioengineered ; 11(1): 1137-1145, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33070676

RESUMO

Staphylococcus aureus is a common foodborne pathogenic microorganism which can cause food poisoning and it is pathogenic to both humans and animals. Therefore, rapid detection of S. aureus infection is of great significance. In this study, a microfluidic platform was introduced to detect S. aureus by fluorescence labeling method and a self-made microfluidic chip, which has immune spheres were used to study the effect of capturing S. aureus. Through this experiment, we found that the platform can be used for microbial culture, and S. aureus antibody coated on the diameter of 50 ~ 90 µm microspheres for detection. On the premise of optimizing the sample flow rate and detection time, the bacterial detection was quantitatively monitored. Results showed that our platform can detect S. aureus at injection rate of 5 µL·min-1 reacted for 4 min and the detection limit of bacteria is 1.5 × 101 CFU/µL. However, the detection time of traditional method is 24 hs to 72 hs, and the operation is complex and cumbersome. These findings indicated that the microfluidic chip in this study is portable, sensitive, and accurate, laying a good foundation for further research on the application of rapid bacterial detection platform.

4.
Front Psychol ; 11: 1870, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32849097

RESUMO

In this study, entrepreneurship education was explored from the perspective of the combination of psychology and literary ethics, with the purpose of studying the entrepreneurial behavior of Chinese American college students and promoting the development of entrepreneurship education. Based on the analysis of self-efficacy, the correlations among entrepreneurial intention, entrepreneurship education, and entrepreneurial efficacy of the research samples were analyzed. First, through the questionnaire design, the research samples and the measurement scales of each research variable were determined, and the survey results and the reliability of the scale were analyzed and tested. Second, based on the variance analysis and regression analysis methods, a descriptive statistical analysis was performed on the correlations among entrepreneurship education, entrepreneurial intentions, and entrepreneurial efficacy among Chinese American college students. Finally, the idea of literary ethics was integrated into entrepreneurship education, entrepreneurial intentions, and entrepreneurial self-efficacy, and the correlation structure model was constructed. The intermediary role of entrepreneurial efficacy in entrepreneurship education and entrepreneurial intention was tested. In addition, the individual gender and family entrepreneurial behaviors were considered. The results show that the valid response rate of the questionnaire, is satisfactory at, 96.49%; the reliability and validity of the scales of the research variables are satisfactory; the Cronbach's Alpha reliability coefficient values are all above 0.80; and the fitting results of the confirmatory factors are satisfactory. The regression analysis results show significant correlations among entrepreneurship education, entrepreneurial intentions, and entrepreneurial efficacy among Chinese American college students. Entrepreneurial efficacy has a partially intermediary role in the two dimensions of entrepreneurship education and entrepreneurial intention. Individual gender and family entrepreneurial behaviors have moderating effects, on the entrepreneurial efficacy levels of college entrepreneurs. From the perspectives of psychology and literary ethics, the above results have positive effects on the development of entrepreneurship education.

5.
Food Nutr Res ; 642020.
Artigo em Inglês | MEDLINE | ID: mdl-32821255

RESUMO

Background: Supplementation of fish oil has been shown to exert beneficial effects in patients undergoing hemodialysis. The aim of this study was to investigate the efficacy of fish oil in improving the quality of life of these patients through a randomized, double-blinded clinical trial. Methods: Among the 103 patients enrolled in the study, a total of 74 patients were randomized to receive fish oil (intervention group) or placebo (n=37 per group). Patients received identical soft-gel capsules, with each capsule containing either 1000 mg fish oil or placebo for 4 months. Personnel responsible for data collection and analyses were blinded to the grouping. Results: The reduction of protein-energy wasting (PEW) in the intervention group was significantly more prominent compared to the placebo group (P=0.023). The intervention group demonstrated significant increase in midarm circumference, arm muscle circumference, and triceps skinfold thickness after fish oil intake. The intervention group also exhibited significant differences from the placebo group in creatinine, uric acid, and serum calcium levels. Significant improvement was seen regarding the physical role and energy/figure in the intervention group. Conclusions: Our study demonstrated that fish oil intake in patient undergoing hemodialysis can significantly reduce PEW, and improve physical and biochemical parameters and quality of life, which could provide guidance to clinical management of these patients.

6.
Cancers (Basel) ; 12(8)2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823758

RESUMO

Oral squamous cell carcinoma (OSCC) accounts for >90% of cases of oral cancer, including cancer at the lip and oral cavity and cancer at the oropharynx. Most OSCCs develop from oral potentially malignant disorders (OPMDs), which consist of heterogeneous lesions with different malignant transformation potentials that make early detection of OSCC a challenge. Using a targeted mass spectrometry-based assay to compare multiple candidate proteins, we previously identified matrix metalloproteinase-1 (MMP-1) as one of the most promising salivary OSCC biomarkers. To explore the clinical utility of MMP-1 in OSCC detection, we developed an in-house, sensitive enzyme-linked immunosorbent assay (ELISA) for measuring MMP-1 content, and tested it on saliva samples from 1160 subjects (313 healthy controls, and 578 OPMD and 269 OSCC patients) collected at two medical centers. Salivary MMP-1 levels measured by our in-house ELISA significantly discriminated OSCC patients from non-cancerous groups. A receiver operating characteristic curve analysis showed that MMP-1 was effective in separating non-cancer groups from patients with OSCCs at the oral cavity. Additionally, salivary MMP-1 levels in oral cavity cancer patients were highly correlated with tumor progression (tumor size, lymph node metastasis, and overall stage). Collectively, our results indicate that salivary MMP-1 is an effective biomarker for OSCC that can be sensitively detected using our newly developed ELISA. The newly developed MMP-1 ELISA may be used as a new adjunctive tool to aid in detecting and monitoring OSCC.

7.
Anal Chim Acta ; 1125: 210-219, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32674768

RESUMO

Electroactive polypyrrole-molybdenum disulfide (MoP) nanocomposites were synthesized and used for modifying screen-printed carbon electrodes (SPCEs) for ultrasensitive detection of berberine, an anticancer drug, in rat plasma. The electroactive nanocomposites were fabricated by exfoliating MoS2 followed by pyrrole polymerization. The effect of polypyrrole in the MoP nanocomposite was evaluated by varying the pyrrole concentration during polymerization, and the resulting nanocomposites prepared with pyrrole concentrations of 10, 20, 30 µL were named as MoP-1, MoP-2, and MoP-3, respectively. The electrochemical characterization of the three MoP nanocomposite sensors revealed that MoP-2/SPCE exhibited the highest electroactivity. The detection of berberine by the three MoP-coated SPCEs revealed that MoP-2/SPCE exhibited the highest activity against berberine due to a two-electron transfer mechanism on the MoP-2/SPCE electrode surface. The detection limit of berberine using the MoP-2/SPCE sensor was found to be about 0.05 µM, which is remarkably lower than the reported detection limits. The interference study proved the selectivity of the MoP-2/SPCE sensor toward berberine in the presence of other bioactive molecules and metal ions. The designed MoP-2/SPCE sensor retained 92% of its initial activity after 15 days of storage at room temperature, with RSD values of about 2.95% and 3.68% for the repeatability and reproducibility studies. Finally, the detection limit of berberine in a rat plasma sample determined using the MoP-2/SPCE sensor was found to be about 5 µM.

8.
Int Immunopharmacol ; 85: 106664, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32521490

RESUMO

Bacillus anthracis is a lethal agent of anthrax disease and the toxins are required in anthrax pathogenesis. The anthrax lethal toxin can trigger NLRP1b inflammasome activation and pyroptosis. Although the underlying mechanism is well understood, the medications targeting the NLRP1b inflammasome are not available in the clinic. Herein, we describe that BPTES, a known Glutaminase (GLS) inhibitor, is an effective NLRP1b inflammasome inhibitor. BPTES could effectively and specifically suppress NLRP1b inflammasome activation in macrophages but have no effects on NLRP3, NLRC4 and AIM2 inflammasome activation. Mechanistically, BPTES alleviated the UBR2 mediated proteasomal degradation pathway of the NLRP1b N terminus, thus blocking the release of the CARD domain for subsequent caspase-1 processing. Furthermore, BPTES could prevent disease progression in mice challenged with the anthrax lethal toxin. Taken together, our studies indicate that BPTES can be a promising pharmacological inhibitor to treat anthrax lethal toxin-related inflammatory diseases.

9.
Adv Mater ; 32(25): e2001879, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32406075

RESUMO

Stimuli-responsive micro/nanostructures that can dynamically and reversibly adapt their configurations according to external stimuli have stimulated a wide scope of engineering applications, ranging from material surface engineering to micromanipulations. However, it remains a challenge to achieve a precise local control of the actuation to realize applications that require heterogeneous and on-demand responses. Here, a new experimental technique is developed for large arrays of hybrid magnetic micropillars and achieve precise local control of actuation using a simple magnetic field. By manipulating the spatial distribution of magnetic nanoparticles within individual elastomer micropillars, a wide range of the magnetomechanical responses from less than 5% to ≈50% for the ratio of the bending deflection to the original length of the pillars is realized. It is demonstrated that the micropillars with different degrees of bending deformation can be configured in any spatial pattern using a photomask-assisted template-casting technique to achieve heterogeneous, site-specific, and programmed bending actuations. This unprecedented local control of the micropillars offers exciting novel applications, as demonstrated here in encryptable surface printing and stamping, direction- and track-programmable microparticle/droplet transport, and smart magnetic micro-tweezers. The hybrid magnetic micropillars reported here provide a versatile prototype for heterogeneous and on-demand actuation using programmable stimuli-responsive micro/nanostructures.

10.
Analyst ; 145(11): 3931-3938, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32314762

RESUMO

A novel method for quantitative detection of the viability of a single microalgae cell by two-level photoexcitation is proposed in this paper. This method overcomes the difficulty of traditional methods in determining the cell viability by a fixed standard under a single photoexcitation. It is experimentally confirmed that this method is not limited by the species, morphology, size and structure of microalgae cells. An evaluation criterion of universal applicability is presented for the assessment of cell viability based on the large amount of experimental data. To the best of our knowledge, this is the first time that the relative fluorescence yield ratio Fr has been used to characterize the viability of single microalgae cells during cell migration. By using the relative fluorescence yield ratio, this method does not require the intensity of the excitation light to be very low for the assessment of the fluorescence yield of a dark-adapted microalgae cell, nor to be very strong to reach the saturated light level to assess the maximum fluorescence yield. Therefore, this method greatly reduces the technical difficulties of developing a sensor device. Well balanced portability, accuracy and universal applicability make it suitable for on-site real-time detection.

11.
Mater Sci Eng C Mater Biol Appl ; 110: 110676, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32204104

RESUMO

Obesity and type 2 diabetes have become serious health problems in 21st century. Development of non-invasive treatment to treat obesity and type-2 diabetes is still unmet needs. For targeting on this, one of the promising treatments is to implant an intestine sleeve in the gastrointestinal tract for limitation of food absorption. In this context, biodegradable polymer intestine sleeve was composed of polycaprolactone (PCL), poly-DL-lactic acid (PDLLA) and disk-shape nano-clay (Laponite®), and fabricated as an implantable device. Here, Laponite® as a rheological additive to improve the compatibility of PCL and PDLLA, and the polymers/clay composites were also evaluated by scanning electron microscopy SEM analysis and mechanical measurements. The mass ratio 90/10/1 of PCL/PDLLA/Laponite® composite was selected for fabrication of intestine sleeve, because of the highest toughness and flexibility, which are tensile strength of 91.9 N/mm2 and tensile strain of 448% at the failure point. The prepared intestine sleeve was implanted and deployed at the duodenum in type2 diabetic rats, providing significant benefits in control of the body weight and blood glucose, while compared with the non-implanted type 2 diabetic rats. More importantly, the food intake records and histopathological section reports presented that the implanted rats still have normal appetites and no noticeable acute symptoms of inflammation in the end of the test. These appreciable performances suggested the implantation of biocompatible polymer composites has a highly potential treatment for obesity and type 2 diabetes.

12.
Sensors (Basel) ; 20(3)2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32012957

RESUMO

In remote-sensing images, a detected oil-spill area is usually affected by spot noise and uneven intensity, which leads to poor segmentation of the oil-spill area. This paper introduced a deep semantic segmentation method that combined a deep-convolution neural network with the fully connected conditional random field to form an end-to-end connection. On the basis of Resnet, it first roughly segmented a multisource remote-sensing image as input by the deep convolutional neural network. Then, we used the Gaussian pairwise method and mean-field approximation. The conditional random field was established as the output of the recurrent neural network. The oil-spill area on the sea surface was monitored by the multisource remote-sensing image and was estimated by optical image. We experimentally compared the proposed method with other models on the dataset established by the multisensory satellite image. Results showed that the method improved classification accuracy and captured fine details of the oil-spill area. The mean intersection over the union was 82.1%, and the monitoring effect was obviously improved.

13.
Analyst ; 145(5): 1605-1628, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31970360

RESUMO

Optical biosensors have exhibited worthwhile performance in detecting biological systems and promoting significant advances in clinical diagnostics, drug discovery, food process control, and environmental monitoring. Without complexity in their pretreatment and probable influence on the nature of target molecules, these biosensors have additional advantages such as high sensitivity, robustness, reliability, and potential to be integrated on a single chip. In this review, the state of the art optical biosensor technologies, including those based on surface plasmon resonance (SPR), optical waveguides, optical resonators, photonic crystals, and optical fibers, are presented. The principles for each type of biosensor are concisely introduced and particular emphasis has been placed on recent achievements. The strengths and weaknesses of each type of biosensor have been outlined as well. Concluding remarks regarding the perspectives of future developments are discussed.


Assuntos
Técnicas Biossensoriais/métodos , Tecnologia de Fibra Óptica/métodos , Proteínas Luminescentes/análise , Imagem Óptica/métodos , Humanos
14.
Materials (Basel) ; 12(24)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817279

RESUMO

The intumescent flame retardant ethylene-propylene-diene rubber (EPDM) was prepared using intumescent flame retardant (IFR), including ammonium polyphosphate (APP) /pentaerythrotol (PER) and expandable graphite (EG), as the flame retardant agent. The effects of IFR and EG on the flame retardancy, fire behavior, and thermal stability of the EPDM were investigated. The results show that IFR and EG have excellent synergistic flame retardant effects. When the mass ratio of IFR to EG is 3:1 and the total addition content is 40 phr, the limiting oxygen index (LOI) value of the EPDM material (EPDM/IFR/EG) can reach 30.4%, and it can pass a V-0 rating in the vertical combustion (UL-94) test. Meanwhile, during the cone calorimetry test, the heat release rate and total heat release of EPDM/IFR/EG are 69.0% and 33.3% lower than that of the pure EPDM, respectively, and the smoke release of the material also decreases significantly, suggesting that the sample shows good fire safety. In addition, the flame retardant mechanism of IFR and EG is systematically investigated by thermogravimetric analysis/infrared spectrometry (TG-IR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), and the results indicate that IFR and EG have only physical interaction. Moreover, the reason why IFR exhibits a poor flame retardant effect in EPDM materials is explained.

15.
Sensors (Basel) ; 19(22)2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31766178

RESUMO

There are a huge number, and abundant types, of microalgae in the ocean; and most of them have various values in many fields, such as food, medicine, energy, feed, etc. Therefore, how to identify and separation of microalgae cells quickly and effectively is a prerequisite for the microalgae research and utilization. Herein, we propose a microfluidic system that comprised microalgae cell separation, treatment and viability characterization. Specifically, the microfluidic separation function is based on the principle of deterministic lateral displacement (DLD), which can separate various microalgae species rapidly by their different sizes. Moreover, a concentration gradient generator is designed in this system to automatically produce gradient concentrations of chemical reagents to optimize the chemical treatment of samples. Finally, a single photon counter was used to evaluate the viability of treated microalgae based on laser-induced fluorescence from the intracellular chlorophyll of microalgae. To the best of our knowledge, this is the first laboratory prototype system combining DLD separation, concentration gradient generator and chlorophyll fluorescence detection technology for fast analysis and treatment of microalgae using marine samples. This study may inspire other novel applications of micro-analytical devices for utilization of microalgae resources, marine ecological environment protection and ship ballast water management.


Assuntos
Separação Celular/instrumentação , Microalgas/citologia , Microfluídica/instrumentação , Sobrevivência Celular , Fluorescência , Movimento , Reologia , Soluções
16.
Pathol Res Pract ; 215(11): 152638, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31551175

RESUMO

AIM: Long non-coding RNA (lncRNA) is currently considered to play an important regulatory role in various diseases, including tumors, at present a hot topic in research. As a non-coding transcription product of imprinted gene, LncRNA H19 is expressed as a parent imprinted maternal allele without protein-coding ability. Increasing evidence indicates that LncH19 may be a new tumor marker for early clinical diagnosis and prognosis judgment. In this study, LncH19 expression was investigated by RNA in situ hybridization for further exploring the clinicopathological role of its expression in esophageal squamous cell cancer (ESCC). METHODS: 121 tumor samples and seven cases of adjacent non-tumor tissues from esophageal cancer patients were detected by RNA in situ hybridization (ISH) and the ISH staining was graded with modified Allred scoring. RESULTS: While no LncH19 expression in the tumor adjacent to normal epithelia was disclosed with the technology, significantly higher levels of LncH19 expression were detected in the tumors obtained from the patients who died within one year after surgery, compared to the expression in those tumors from the patients who survived longer than five years after the same treatment regimen (P = 0.001). In addition, LncH19 expression was verified to correlate with a larger tumor size (P = 0.002) and a higher UICC stage (P = 0.001). CONCLUSION: Our LncH19 ISH data verify the involvement of LncH19 in ESCC. Higher levels of LncH19 expression were not only detected in tumors with larger size and in clinical late stage, but also significantly associated with shorter survival, strongly indicating its clinical significance in the malignant progression of ESCC and useful value as a poor prognostic factor for the patients.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas do Esôfago/genética , RNA Longo não Codificante/biossíntese , Adulto , Idoso , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/mortalidade , Carcinoma de Células Escamosas do Esôfago/patologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Prognóstico
17.
Mol Biol Rep ; 46(6): 6003-6011, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31446531

RESUMO

Paeonia ostii seeds have recently been identified as a new source of α-linolenic acid in China. Studying the gene expression patterns of unsaturated fatty acid-related genes would be helpful for understanding the mechanism of α-linolenic acid accumulation. Quantitative real-time polymerase chain reaction (qRT-PCR) is a useful method for reliably evaluating gene expression, and it is necessary to select reliable reference genes for data normalization in qRT-PCR analysis. In this study, we evaluated the expression stability of 12 candidate reference genes using four mathematical algorithms (∆Ct, BestKeeper, NormFinder, and geNorm). The web-based tool RefFinder was used to integrate the results and to provide a comprehensive ranking order. The expression stability ranking orders of reference genes were different caculated by these four algorithms, and the ranking order analyzed by the RefFinder was UBQ > Tip41 > UCE > EF-1α > α-TUB > PP2A > ACT > GAPDH > SAM > CYP > ß-TUB > 18S at the different seed development stages, and UBQ > Tip41 > EF-1α > α-TUB > PP2A > UCE > GAPDH > SAM > ACT > CYP > 18S > ß-TUB in P. ostii tissues. UBQ and Tip41 are the two most stable whereas 18S and ß-TUB are the two least stable reference genes for gene expression in various tissues and seeds at different developmental stages in P. ostii.


Assuntos
Perfilação da Expressão Gênica/normas , Paeonia/genética , Padrões de Referência , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase em Tempo Real/normas
18.
Electrophoresis ; 40(6): 922-929, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30597589

RESUMO

Spatial microgravity is a significant factor affecting and causing physiological changes of organisms in space environment. On-site assessment of the damage associated to microgravity is very important for future long-term space exploration of mankind. In this paper, a new microfluidic device for analyzing the damage of microgravity on Caenorhabditis elegans (C. elegans) has been developed. This device is mainly composed of a microfluidic chip, a dual imaging module, and an imaging acquisition and processing module, which are integrated into a compact system. The microfluidic chip is designed as a platform for monitoring C. elegans, which is captured in an imaging region through a suction structure in the microfluidic chip. A dual imaging module is designed to obtain the images of bright field and fluorescence of C. elegans. The behaviors of C. elegans are analyzed based on the dual-mode imaging of bright field and fluorescence to assess the degree of damage due to microgravity. A comparative study using a commercial microscope is also conducted to demonstrate the unique advantage of the developed system under the simulated microgravity. The results show that the developed system can evaluate the damage of C. elegans under microgravity accurately and conveniently. Furthermore, this device has compact size and weight, easy operation, and low-cost, which could be highly advantageous for on-site evaluation of the damage to microorganisms under microgravity in a space station.


Assuntos
Caenorhabditis elegans/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas , Ausência de Peso/efeitos adversos , Animais , Desenho de Equipamento , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos
19.
Electrophoresis ; 40(6): 969-978, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30221789

RESUMO

The composition of the ship's ballast water is complex and contains a large number of microalgae cells, bacteria, microplastics, and other microparticles. To increase the accuracy and efficiency of detection of the microalgae cells in ballast water, a new microfluidic chip for continuous separation of microalgae cells based on alternating current dielectrophoresis was proposed. In this microfluidic chip, one piece of 3-dimensional electrode is embedded on one side and eight discrete electrodes are arranged on the other side of the microchannel. An insulated triangular structure between electrodes is designed for increasing the inhomogeneity of the electric field distribution and enhancing the dielectrophoresis (DEP) force. A sheath flow is designed to focus the microparticles near the electrode, so as to increase the suffered DEP force and improve separation efficiency. To demonstrate the performance of the microfluidic separation chip, we developed two species of microalgae cells (Platymonas and Closterium) and a kind of microplastics to be used as test samples. Analyses of the related parameters and separation experiments by our designed microfluidic chip were then conducted. The results show that the presented method can separate the microalgae cells from the mixture efficiently, and this is the first time to separate two or more species of microalgae cells in a microfluidic chip by using negative and positive DEP force simultaneously, and moreover it has some advantages including simple operation, high efficiency, low cost, and small size and has great potential in on-site pretreatment of ballast water.


Assuntos
Eletroforese , Dispositivos Lab-On-A-Chip , Microalgas , Navios , Microbiologia da Água , Clorófitas/citologia , Closterium/citologia , Eletroforese/instrumentação , Eletroforese/métodos , Desenho de Equipamento , Microalgas/citologia , Microalgas/isolamento & purificação , Poliestirenos
20.
IEEE Trans Cybern ; 49(8): 3020-3031, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29994347

RESUMO

Most of the existing stealthy attack schemes for cyber-physical systems (CPSs) are presented under the assumption that the model parameters of CPS are known to attackers. Presently, there are only a few model-independent stealthy attack approaches, which, however, need the assumption that attackers know sensor measurements and can modify them. This paper aims to remove the aforementioned conservative assumptions and give a stealthy attack methodology for closed-loop CPS with reference signals, that is, transmission control protocol/Internet protocol (TCP/IP)-based networked control systems. To this end, under the condition that the model parameters of the CPS are unknown, a benchmark platform (consisting of an attack detector and a TCP/IP-based networked dc servo system) used for testing the stealthy attack technology is constructed via data-driven methods. A plan is made, which is utilized for eavesdropping the information of the TCP/IP-based CPS. On this basis, an approach to blocking network communications and injecting the false sensor data into the CPS is explored. A closed-loop recursive identification strategy for the dynamic characteristic matrix of the CPS is designed. By employing all of the above-obtained results, a data-driven stealthy attack scheme for the CPS is proposed and, subsequently, its effectiveness and practicability are validated by experiment.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA