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1.
Theranostics ; 11(12): 5926-5938, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33897890

RESUMO

Metabolic reprogramming, especially Warburg effect, is a key event in tumor initiation and progression. ZEB1 plays a vital role in metastasis of various cancers. We previously found that ZEB1 was excessively expressed in hepatocellular carcinoma (HCC) and its high expression was closely correlated with metastasis and recurrence of HCC. We want to know whether glycolytic enzymes are regulated by ZEB1 and contribute to carcinogenesis and metastasis of HCC. Methods: To explore whether ZEB1 could enhance glycolysis in HCC, we knocked down ZEB1 by short hairpin RNA (shRNA) in MHCC-97H and HCC-LM3 cells and performed glucose uptake, lactate production, ECAR and OCR assays. To investigate how ZEB1 enhances glycolysis, the protein levels of glycolytic enzymes were detected in the same cell lines using Western blot. The regulatory effect of ZEB1 on PFKM mRNA level was confirmed by RT-qPCR, luciferase report assay and ChIP assay. In order to assess the role of ZEB1-PFKM axis in cell proliferation, cell counting and CCK-8 assays were performed in MHCC-97H and HCC-LM3 cell lines knocked down for ZEB1 and further re-expressed for either ZEB1 or PFKM or not. To explored whether the ZEB1-PFKM axis also functions in HCC cell migration, invasion and metastasis, the same MHCC-97H and HCC-LM3 cell lines were performed for wound healing assays, transwell assays and colony formation assays, meanwhile, MHCC-97H cell lines were performed for orthotopic liver transplantation assays. Finally, the expression of ZEB1 and PFKM were examined in human liver cancer specimens and non-tumorous liver tissues using immunohistochemical and Western blot. Results: We found that ZEB1 transcriptionally upregulates the expression of the muscle isoform of phosphofructokinase-1 (PFKM), a rate-limiting enzyme in glycolysis. Intriguingly, a non-classic ZEB1-binding sequence in the promoter region of PFKM was identified through which ZEB1 directly activates the transcription of PFKM. Silencing of ZEB1 in MHCC-97H and HCC-LM3 cell leads to impaired PFKM expression, glycolysis, proliferation and invasion, and such impairments are rescued by exogenous expression of PFKM. Importantly, in-situ HCC xenograft assays and studies from TCGA database demonstrate that ZEB1-PFKM axis is crucial for carcinogenesis and metastasis of HCC. Conclusions: Our study reveals a novel mechanism of ZEB1 in promoting HCC by activating the transcription of PFKM, establishing the direct link of ZEB1 to the promotion of glycolysis and Warburg effect and suggesting that inhibition of ZEB1 transcriptional activity toward PFKM may be a potential therapeutic strategy for HCC.

2.
IEEE Trans Med Imaging ; 40(5): 1363-1376, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33507867

RESUMO

To better understand early brain development in health and disorder, it is critical to accurately segment infant brain magnetic resonance (MR) images into white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF). Deep learning-based methods have achieved state-of-the-art performance; h owever, one of the major limitations is that the learning-based methods may suffer from the multi-site issue, that is, the models trained on a dataset from one site may not be applicable to the datasets acquired from other sites with different imaging protocols/scanners. To promote methodological development in the community, the iSeg-2019 challenge (http://iseg2019.web.unc.edu) provides a set of 6-month infant subjects from multiple sites with different protocols/scanners for the participating methods. T raining/validation subjects are from UNC (MAP) and testing subjects are from UNC/UMN (BCP), Stanford University, and Emory University. By the time of writing, there are 30 automatic segmentation methods participated in the iSeg-2019. In this article, 8 top-ranked methods were reviewed by detailing their pipelines/implementations, presenting experimental results, and evaluating performance across different sites in terms of whole brain, regions of interest, and gyral landmark curves. We further pointed out their limitations and possible directions for addressing the multi-site issue. We find that multi-site consistency is still an open issue. We hope that the multi-site dataset in the iSeg-2019 and this review article will attract more researchers to address the challenging and critical multi-site issue in practice.

3.
J Am Chem Soc ; 142(19): 8679-8687, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32315166

RESUMO

The proton affinity (PA) of a neutral molecule is defined as the negative of the enthalpy change for the gas-phase reaction between a proton and the neutral molecule to produce the (charged) conjugate acid of the molecule. PA is a fundamental property that is related to the structure of a molecule and affects its reactivity. Very few PA values are available for basic organic monoradicals and none for biradicals. Here, the PA values for several σ-type carbon-centered pyridine-based monoradicals and biradicals have been experimentally determined by monitoring proton transfer from the protonated mono- and biradicals to reference bases with known proton affinities as a function of time in Fourier-transform ion cyclotron resonance (FT-ICR) and linear quadrupole ion trap (LQIT) mass spectrometers. A procedure was developed for both instruments that permits differentiation between exo- and endothermic proton transfer reactions. The PA values of all the (bi)radicals studied were found to be lower than that of pyridine. This is rationalized based on the electron-withdrawing nature of the radical site(s). Thus, the PA values decrease in the order: pyridine > monoradicals > biradicals. The PA values of the monoradicals were also found to increase (making the protonated radicals less acidic) as the distance between the basic nitrogen atom and the radical site increases. Similar behavior was found for the biradicals, with one exception: 3,5-didehydropyridine has a larger PA (215.3 ± 3.3 kcal mol-1) than 3,4-didehydropyridine (PA = 213.4 ± 3.3 kcal mol-1) even though the latter biradical has one radical site farther away from the basic nitrogen atom. Quantum chemical calculations of the PAs of the (bi)radicals are in reasonably good agreement with the experimentally determined values. At the DFT (B3LYP), CCSD(T), and CASPT2 levels of theory, the mean unsigned errors are 2.3, 1.7, and 2.1 kcal mol-1.

4.
Pest Manag Sci ; 76(9): 3159-3167, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32333521

RESUMO

BACKGROUND: The insect olfactory system can recognize odorants for feeding, courtship, oviposition and avoiding natural enemies. Odorant cues from host plants play important roles in insect behaviours. Tobacco (Nicotiana tabacum) is the main cultivated host of the oriental tobacco budworm Helicoverpa assult. Volatiles of tobacco plants attract and stimulate oviposition in female moths. However, it is still not known how female H. assulta recognize tobacco volatiles and which odorant compounds are used as oviposition cues. RESULTS: We detected 14 volatile compounds emitted from a tobacco plant during vegetative growth, using gas chromatography-mass spectrometry. Electroantennogram tests indicated that eight of the 14 compounds induced responses in female H. assulta. Among these eight volatiles, nonanal greatly increased oviposition preference. Single-sensillum recording (SSR) results showed that many neurons housed in three types of short basiconic sensilla and four types of long basiconic sensilla responded to nonanal and heptanal as its structural analogue. The responses to nonanal were significantly stronger than those to the other compounds. Nonanal was the main ligand of OR67, an odorant receptor from H. assulta. This was demonstrated using an in vitro Xenopus oocytes expression system that supported the SSR results. CONCLUSION: Nonanal is a key signal volatile of tobacco plants that attracts female H. assulta moths to oviposit. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

6.
Chemosphere ; 248: 126019, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32007775

RESUMO

Silkworm (Bombyx mori L.) has a clear genetic background, parts of which are highly homologous to certain genes related to human hereditary diseases. Thus, the species presents an excellent interspecies model for drug screening and microbe-host interaction studies. Chloramphenicol (CAM) and vancomycin (VCM) are antibiotics commonly used to treat specific bacterial infections in medical care, animal husbandry, and agriculture. However, inappropriate dosages and prolonged therapy increase their risk of toxicity. In this work, we investigated the physiological and toxicological responses of silkworm to combined oral administration of CAM and VCM. Results showed that antibiotics promote the feeding behavior of silkworm and significantly reduce (P < 0.05) intestinal cultivable bacterial counts. Moreover, antibiotics decreased the antioxidant enzyme activities of superoxide dismutase, catalase, glutathione S-transferase, and thioredoxin reductase and caused oxidative damage to the silkworm intestine; the degree of damage was confirmed by histopathology analysis. The gene expression levels of antimicrobial peptides (attacin, lysozyme, and cecropins) were also perturbed by antibiotics. After antibiotic exposure, 16S rRNA metagenomic sequencing revealed increases in the relative abundance of Sphingobium, Burkholderia, Barnesiella, Bacteroides, Bradyrhizobium, Acinetobacter, Phenylobacterium, Plesiomonas, Escherichia/Shigella, and unclassified bacteria, as well as a reduction of Enterococcus. The metabolic and functional profiles of intestinal microbiota, particularly metabolic processes, such as energy, cofactors and vitamins, lipid, amino acid, and carbohydrate metabolisms, changed after antibiotic exposure. In conclusion, our findings reveal that antibiotics exert substantial effects on silkworm. The present study may promote the applications of silkworm as an interspecies model in the medical and pharmaceutical fields.


Assuntos
Antibacterianos/toxicidade , Insetos , Animais , Bactérias/genética , Bombyx/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Expressão Gênica , Proteínas de Insetos , Intestinos/microbiologia , Modelos Biológicos , RNA Ribossômico 16S/genética , Especificidade da Espécie , Testes de Toxicidade
7.
Nat Commun ; 11(1): 401, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964879

RESUMO

Magnesium-based biodegradable metals (BMs) as bone implants have better mechanical properties than biodegradable polymers, yet their strength is roughly less than 350 MPa. In this work, binary Zn alloys with alloying elements Mg, Ca, Sr, Li, Mn, Fe, Cu, and Ag respectively, are screened systemically by in vitro and in vivo studies. Li exhibits the most effective strengthening role in Zn, followed by Mg. Alloying leads to accelerated degradation, but adequate mechanical integrity can be expected for Zn alloys when considering bone fracture healing. Adding elements Mg, Ca, Sr and Li into Zn can improve the cytocompatibility, osteogenesis, and osseointegration. Further optimization of the ternary Zn-Li alloy system results in Zn-0.8Li-0.4Mg alloy with the ultimate tensile strength 646.69 ± 12.79 MPa and Zn-0.8Li-0.8Mn alloy with elongation 103.27 ± 20%. In summary, biocompatible Zn-based BMs with strength close to pure Ti are promising candidates in orthopedics for load-bearing applications.


Assuntos
Implantes Absorvíveis , Ligas/química , Fixadores Internos , Desenho de Prótese , Zinco/química , Animais , Interface Osso-Implante/diagnóstico por imagem , Linhagem Celular , Fêmur/diagnóstico por imagem , Fêmur/cirurgia , Fixação Interna de Fraturas/instrumentação , Células Endoteliais da Veia Umbilical Humana , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Osteoblastos , Ratos , Resistência à Tração , Suporte de Carga , Microtomografia por Raio-X
8.
ACS Appl Mater Interfaces ; 12(5): 5671-5679, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31940177

RESUMO

Dynamically monitoring the clonal evolution of lung cancer and performing molecular analyses on tumor cells are challenging but necessary tasks to adjust therapeutic interventions and evaluate treatment efficacy. Circulating tumor cells (CTCs), as a "liquid biopsy", may offer an auxiliary tool to identify phenotypic transformation of solid tumors at primary or metastatic sites and uncover their corresponding molecular variation. Herein, we developed an aptamer-modified PEG-PLGA-nanofiber (PPN) microfluidic system optimized for recognizing rare CTC subtypes in lung cancer patients. This unique purification system can be adopted to monitor the clonal evolution of solid tumors by following the intrinsic immunophenotypes of CTCs, while significantly enhancing capture efficiency for polyclonal-derived tumor cells, further facilitating therapeutic evaluation via dynamic CTC enumeration. Combining with downstream single-cell sequencing, the aptamer-modified-PPN microfluidic system was able to provide early insight into tumor heterogeneity and predict histologic transformation in advance, broadening its clinical applications in lung cancer patients.


Assuntos
Aptâmeros de Nucleotídeos/genética , Evolução Clonal/genética , Neoplasias Pulmonares , Nanofibras/química , Células Neoplásicas Circulantes/patologia , Animais , Linhagem Celular Tumoral , Humanos , Biópsia Líquida/instrumentação , Biópsia Líquida/métodos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Camundongos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Poliésteres/química , Polietilenoglicóis/química , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Gene ; 726: 144197, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31669636

RESUMO

Enterococcus faecalis is one of the main components of symbiotic bacteria in the intestine of silkworm (Bombyx mori L.). The abundance of E. faecalis in the intestine of silkworm is affected by fluoride exposure. However, the response mechanism of E. faecalis toward fluoride remains largely unknown. In this study, a strain of E. faecalis (named TV4), which is a symbiotic bacteria of silkworm, was isolated and characterized. Inhibition assay showed that fluoride can significantly inhibit the growth of the TV4 strain (P < 0.05) after culture for 4 h. Finally, Illumina X-Ten platform was used to investigate the response mechanism of E. faecalis TV4 under fluoride exposure. We found that the TV4 strain demonstrated significant changes in its carbohydrate transport and metabolism and energy metabolism. The transcriptome sequencing results revealed that 237 genes were differentially expressed for TV4 grown after fluoride exposure, i.e., 92 genes were differentially up-regulated and 145 genes were differentially down-regulated. Many of the down-regulated genes were involved in cell carbohydrate transport and metabolism and energy production, whereas the up-regulated genes were mostly related to ethanolamine utilization and amino acid synthesis and metabolism. Our results revealed that strain TV4 reduced its carbohydrate metabolism and energy metabolism and increased ethanolamine utilization and amino acid metabolism to adapt and survive under fluoride exposure. This study enhances our understanding about the response mechanism of E. faecalis after fluoride exposure and has important implications for investigations on the three-way interaction among fluoride, symbiotic bacteria and silkworm.


Assuntos
Bombyx/microbiologia , Enterococcus faecalis/genética , Fluoretos/efeitos adversos , Animais , Regulação para Baixo/genética , Perfilação da Expressão Gênica/métodos , Intestinos/microbiologia , RNA-Seq , Transcriptoma/genética , Regulação para Cima/genética , Sequenciamento Completo do Exoma/métodos
10.
Curr Genet ; 66(1): 229-243, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31312935

RESUMO

Fusarium pseudograminearum-induced crown rot causes significant reduction to wheat production worldwide. To date, efforts to develop effective resistance to this disease have been hampered by the quantitative nature of resistance trait and a lack of understanding of the molecular pathogenesis. Non-ribosomal peptides have important roles in development, pathogenicity, and toxins in many plant pathogens, while less is known in F. pseudograminearum. In this work, we studied the expression and function of a nonribosomal peptide gene FpNPS9 in F. pseudograminearum. We determined the expression of FpNPS9 which was significantly up regulated during the infection of wheat. A deletion mutant Δfpnps9 produced in this study displayed a normal growth and conidiation phenotype, however, hyphae polar growth was obviously affected. Deoxynivalenol production in this mutant was significantly reduced and the infection of wheat coleoptiles and wheat spikelet was attenuated. The Δfpnps9 showed serious defects on the extension of infectious hyphae in plant and inhibition of roots elongation compared with the wild type. The complementation assay using a FpNPS9-GFP fusion construct fully restored the defects of the mutant. GFP signal was detected in the germinating conidia and infectious hyphae in coleoptiles of the infected plants. Interestingly, the signal was not observed when it was grown on culture medium, suggesting that the expression of FpNPS9 was regulated by an unknown host factor. This observation was supported by the result of qRT-PCR. In summary, we provided new knowledge on FpNPS9 expression in F. pseudograminearum and its function in F. pseudograminearum pathogenicity in wheat.


Assuntos
Proteínas Fúngicas/genética , Fusarium/genética , Proteínas Nucleares/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Triticum/genética , Triticum/microbiologia , Deleção de Genes , Expressão Gênica , Técnicas de Silenciamento de Genes , Recombinação Homóloga
11.
Sensors (Basel) ; 19(23)2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31779193

RESUMO

Polarimetric synthetic aperture radar is an important tool in the effective detection of marine oil spills. In this study, two cases of Radarsat-2 Fine mode quad-polarimetric synthetic aperture radar datasets are exploited to detect a well-known oil seep area that collected over the Gulf of Mexico using the same research area, sensor, and time. A novel oil spill detection scheme based on a multi-polarimetric features model matching method using spectral pan-similarity measure (SPM) is proposed. A multi-polarimetric features curve is generated based on optimal polarimetric features selected using Jeffreys-Matusita distance considering its ability to discriminate between thick and thin oil slicks and seawater. The SPM is used to search for and match homogeneous unlabeled pixels and assign them to a class with the highest similarity to their spectral vector size, spectral curve shape, and spectral information content. The superiority of the SPM for oil spill detection compared to traditional spectral similarity measures is demonstrated for the first time based on accuracy assessments and computational complexity analysis by comparing with four traditional spectral similarity measures, random forest (RF), support vector machine (SVM), and decision tree (DT). Experiment results indicate that the proposed method has better oil spill detection capability, with a higher average accuracy and kappa coefficient (1.5-7.9% and 1-25% higher, respectively) than the four traditional spectral similarity measures under the same computational complexity operations. Furthermore, in most cases, the proposed method produces valuable and acceptable results that are better than the RF, SVM, and DT in terms of accuracy and computational complexity.

12.
Proc IEEE Int Symp Biomed Imaging ; 2019: 1052-1056, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31681457

RESUMO

Currently, autism spectrum disorder (ASD) is mainly diagnosed by the observation of core behavioral symptoms. Consequently, the window of opportunity for effective intervention may have passed, when the disorder is detected until 3 years of age. Thus, it is of great importance to identify imaging-based biomarkers for early diagnosis of ASD. Previous findings indicate that an abnormal pattern of the amygdala and hippocampal development in autism persists through childhood and adolescence. However, due to the low tissue contrast and small structural size of amygdala and hippocampal subfields, our knowledge on their growth in autistics in early stage still remains very limited. In this paper, for the first time, we propose a volume-based analysis of the amygdala and hippocampal subfields of the infant subjects with risk of ASD at around 24 months of age. Specifically, to address the challenge of low tissue contrast, we propose a novel deep-learning approach, i.e., dilated-dense U-Net, to automatically segment the amygdala and hippocampal subfields. Experimental results on National Database for Autism Research (NDAR) show the advantages of our proposed method in terms of segmentation accuracy. Our volume-based analysis shows the overgrowths of amygdala and CA1-3 of hippocampus, which may link to the emergence of autism spectrum disorder.

13.
Cell Rep ; 29(5): 1311-1322.e5, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31665642

RESUMO

The mechanistic target of rapamycin complex 2 (mTORC2) coordinates cell proliferation, survival, and metabolism with environmental inputs, yet how extracellular stimuli such as growth factors (GFs) activate mTORC2 remains enigmatic. Here we demonstrate that in human endothelial cells, activation of mTORC2 signaling by GFs is mediated by transmembrane cell adhesion protein CD146. Upon GF stimulation, the cytoplasmic tail of CD146 is phosphorylated, which permits its positively charged, juxtamembrane KKGK motif to interact with Rictor, the defining subunit of mTORC2. The formation of the CD146-Rictor/mTORC2 complex protects Rictor from ubiquitin-proteasome-mediated degradation, thereby specifically upregulating mTORC2 activity with no intervention of the PI3K and mTORC1 pathways. This CD146-mediated mTORC2 activation in response to GF stimulation promotes cell proliferation and survival. Therefore, our findings identify a molecular mechanism by which extracellular stimuli regulate mTORC2 activity, linking environmental cues with mTORC2 regulation.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais , Motivos de Aminoácidos , Antígeno CD146/química , Antígeno CD146/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Proteínas Mutantes/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Proteína Companheira de mTOR Insensível à Rapamicina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ubiquitina/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia
14.
J Exp Clin Cancer Res ; 38(1): 415, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31615580

RESUMO

In the original publication of this manuscript [1], Fig. 5E lower panel was incorrect due to an error in the preparation of these figures for publication. It was noticed that in the lower panel of Fig. 5E, one mouse image of ApoE-/- + PBS group (upper) was a photograph coming from ApoE-/- + BAPN pre-treatment group (lower). The corrected figure appears below. We apologize for any confusion this may have caused.

15.
Sci Total Environ ; 692: 1282-1290, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539960

RESUMO

Bacillus cereus is a foodborne pathogen that causes gastrointestinal disease in hosts. The interactions between pathogenic bacteria and silkworms (Bombyx mori L.) involve complex processes. This study aimed to investigate the potential genetic traits of B. cereus SW7-1 and profile the toxicity response of silkworm intestine upon infection by the SW7-1 pathogen. Bacterial genome sequencing and polymerase chain reaction (PCR) detection indicated that B. cereus SW7-1 possesses multiple antibiotic-resistant genes and nine virulence factor genes. Then, silkworm larvae were infected with SW7-1. Comparative transcriptomic analysis revealed that 273 differentially expressed genes (DEGs) with known functions were successfully annotated to the silkworm reference genome. Specifically, 18 DEGs were up-regulated, and 255 DEGs were down-regulated. Compared with the control group, the treated group revealed down-regulated DEGs that are related to stress reactions, immunity, autophagy and apoptosis, DNA replication, ribosomal stress, and carbohydrate metabolism. Quantitative real time PCR analysis showed that many key genes in the Toll pathway, immune deficiency pathway, Janus kinase/signal transducers and activators of transcription pathway, and melanization reaction were up-regulated. Thus, B. cereus SW7-1 pathogen could damage the silkworm intestine, as confirmed by the histological section assay. In addition, SW7-1 can affect the normal physiological functions of intestinal cells. This study contributes toward an improved understanding of the toxicity response of silkworm to the B. cereus pathogen and provides new insights into the molecular mechanisms of the complex interactions between pathogenic microbes and silkworms.


Assuntos
Bacillus cereus , Bombyx , Interações Hospedeiro-Patógeno , Intestinos/microbiologia , Animais
16.
Sensors (Basel) ; 19(19)2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31546655

RESUMO

The advent of the swarm makes it feasible to dynamically monitor a wide area for maritime applications. The crucial problems of underwater swarm monitoring are communication and behavior coordination. To tackle these problems, we propose a wide area monitoring strategy that searches for static targets of interest simultaneously. Traditionally, an underwater robot adopts either acoustic communication or optical communication. However, the former is low in bandwidth and the latter is short in communication range. Our strategy coordinates underwater robots through indirect communication, which is inspired by social insects that exchange information by pheromone. The indirect communication is established with the help of a set of underwater communication nodes. We adopt a virtual pheromone-based controller and provide a set of rules to integrate the area of interest into the pheromone. Based on the information in the virtual pheromone, behavior laws are developed to guide the swarm to monitor and search with nearby information. In addition, a robot can improve its performance when using additional far-away pheromone information. The monitoring strategy is further improved by adopting a swarm evolution scheme which automatically adjusts the visiting period. Experimental results show that our strategy is superior to the random strategy in most cases.

17.
Mar Pollut Bull ; 146: 977-984, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426245

RESUMO

As the main fluorescent substances in oils, polycyclic aromatic hydrocarbons (PAHs) are the basis of ultraviolet (UV)-induced fluorescence spectroscopy methods to detect oil films on the sea surface. The relative contents of PAHs in six crude oil samples and their effects on ultraviolet fluorescence spectra were studied. The PAHs were divided into four categories according to their fluorescence characteristics. Naphthalene series dominated the fluorescence spectra, which led to a main peak at 320-350 nm, but this showed no relationship with PAH content. The six oil samples could not be distinguished by differences in the fluorescence spectra in this range, but could be distinguished by the fluorescence spectra in the 350-380 nm band. The relative contents of dibenzothiophene and phenanthrene series showed significant positive correlations (R2 = 0.96) with fluorescence intensity. Fluorescence spectroscopy combined with GC-MS can be used to distinguish and identify crude oils.


Assuntos
Poluição por Petróleo/análise , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Água do Mar/química , Monitoramento Ambiental/normas , Fluorescência , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Policíclicos Aromáticos/análise , Espectrometria de Fluorescência
18.
Acta Biomater ; 97: 23-45, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31349057

RESUMO

To date, more than fifty articles have been published on the feasibility studies of zinc and its alloys as biodegradable metals. These preliminary in vitro and in vivo studies showed acceptable biodegradability and reasonable biocompatibility in bone and blood microenvironments for the experimental Zn-based biodegradable metals and, for some alloy systems, superior mechanical performance over Mg-based biodegradable metals. For instance, the Zn-Li alloys exhibited higher UTS (UTS), and the Zn-Mn alloys exhibited higher elongation (more than 100%). On the one hand, similar to Mg-based biodegradable metals, insufficient strength and ductility, as well as relatively low fatigue strength, may lead to premature failure of medical devices. On the other hand, owing to the low melting point of the element Zn, several new uncertainties with regard to the mechanical properties of biomedical zinc alloys, including low creep resistance, high susceptibility to natural aging, and static recrystallization (SRX), may lead to device failure during storage at room temperature and usage at body temperature. This paper comprehensively reviews studies on these mechanical aspects of industrial Zn and Zn alloys in the last century and biomedical Zn and Zn alloys in this century. The challenges for the future design of biomedical zinc alloys as biodegradable metals to guarantee 100% mechanical compatibility are pointed out, and this will guide the mechanical property design of Zn-based biodegradable metals. STATEMENT OF SIGNIFICANCE: Previous studies on mechanical properties of industrial Zn and Zn alloys in the last century and biomedical Zn and Zn alloys in this century are comprehensively reviewed herein. The challenges for the future design of zinc-based biodegradable materials considering mechanical compatibility are pointed out. Common considerations such as strength, ductility, and fatigue behaviors are covered together with special attention on several new uncertainties including low creep resistance, high susceptibility to natural aging, and static recrystallization (SRX). These new uncertainties, which are not significantly observed in Mg-based and Fe-based materials, are largely due to the low melting point of the element Zn and may lead to device failure during storage at room temperature and clinical usage at body temperature. Future studies are urgently needed on these topics.


Assuntos
Implantes Absorvíveis , Ligas , Materiais Biocompatíveis , Teste de Materiais , Zinco , Ligas/química , Ligas/uso terapêutico , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Humanos , Resistência à Tração , Zinco/química , Zinco/uso terapêutico
19.
ACS Appl Mater Interfaces ; 11(33): 29681-29688, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361461

RESUMO

Cell manipulation has raised extensive concern owing to its underlying applications in numerous biological situations such as cell-matrix interaction, tissue engineering, and cell-based diagnosis. Generally, light is considered as a superior candidate for manipulating cells (e.g., cell release) due to their high spatiotemporal precision and non-invasion. However, it remains a big challenge to release cells with high efficiency due to their potential limitation of the light-triggered wettability transition on photoresponsive surfaces. In this study, we report a photoresponsive spiropyran-coated nanostructured surface that enables highly efficient release of cancer cells, amplified by the introduction of a photo-irresponsive molecule. On one hand, structural recognition stems from topological interaction between nanofractal surfaces and the protrusions of cancer cells. On the other, molecular recognition can be amplified by a photo-irresponsive and hydrophilic molecule by reducing the steric hindrance of photoresponsive components and resisting nonspecific cell adhesion. Therefore, this study may afford a novel avenue for developing advanced smart materials for high-quality biological analysis and clinical diagnosis.


Assuntos
Benzopiranos/química , Indóis/química , Nanoestruturas/química , Nitrocompostos/química , Adesão Celular/efeitos dos fármacos , Adesão Celular/efeitos da radiação , Humanos , Luz , Células MCF-7 , Molhabilidade
20.
PLoS One ; 14(4): e0214460, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30939170

RESUMO

OBJECTIVE: To design and evaluate the accuracy of a novel navigation template suitable for posterior cervical screw placement surgery by using 3D printing technology to improve the existing guiding template design. METHODS: The researchers (including spine surgeons and technicians) used CT to perform thin-slice scanning on 12 cases of normal upper cervical vertebral specimens and defined the screw channels that were completely located in the pedicle without penetrating the cortex as ideal screw channels, then designed the ideal channel of the upper cervical vertebral (atlantoaxial) pedicle screw by computer software which was regarded as the preset values, and recorded the screw entrance point, transverse angle and sagittal angle of the ideal channel. Then, researchers designed the novel navigation templates for placement pedicle screw according to the ideal screw channel preset values and manufactured them with one for every single vertebra by 3D printer. A senior spine surgeon performed the posterior surgery to implant pedicle screw on the specimens by the novel navigation templates, then performed CT thin-slice scanning on the specimens again after removing the screws, and reconstructed the actual screws channel by computer software, recorded the screw entrance point, transverse angle and sagittal angle of the actual channels which were defined as the actual values and evaluated them according to Kawaguchi's pedicle screw evaluation standard finally. The differences between the preoperative preset values of ideal screw channel and the postoperative actual values of actual screw channel were compared by a nonparametric paired rank test. RESULTS: 48 screws were placed on 12 cases of upper cervical vertebral specimens in total. It showed that the grade 0, I, II, III channels in this study were 47, 1, 0, 0, respectively. The grade 0 channels accounted for 97.92% of the total number of channels. There was no significant difference with regard to the screw entrance point, the transverse angle, and the sagittal angle between the preoperative preset values of ideal screw channels and the postoperative actual values of actual screw channels. CONCLUSION: To implant pedicle screw assisted with the novel individually navigation template designed by 3D printed in the posterior cervical surgery can improve accuracy of pedicle screw placement and safety of the surgery.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Parafusos Pediculares , Impressão Tridimensional , Fusão Vertebral/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Vértebras Cervicais/cirurgia , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Risco , Cirurgia Assistida por Computador/métodos
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