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1.
J Hazard Mater ; 470: 134038, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38552392

RESUMO

Millions of people worldwide are affected by naturally occurring arsenic in groundwater. The development of a low-cost, highly sensitive, portable assay for rapid field detection of arsenic in water is important to identify areas for safe wells and to help prioritize testing. Herein, a novel paper-based fluorescence assay was developed for the on-site analysis of arsenic, which was constructed by the solid-phase fluorescence filter effect (SPFFE) of AsH3-induced the generation of silver nanoparticles (AgNPs) toward carbon dots. The proposed SPFFE-based assay achieves a low arsenic detection limit of 0.36 µg/L due to the efficient reduction of Ag+ by AsH3 and the high molar extinction coefficient of AgNPs. In conjunction with a smartphone and an integrated sample processing and sensing platform, field-sensitive detection of arsenic could be achieved. The accuracy of the portable assay was validated by successfully analyzing surface and groundwater samples, with no significant difference from the results obtained through mass spectrometry. Compared to other methods for arsenic analysis, this developed system offers excellent sensitivity, portability, and low cost. It holds promising potential for on-site analysis of arsenic in groundwater to identify safe well locations and quickly obtain output from the global map of groundwater arsenic.

2.
Anal Chem ; 96(11): 4665-4672, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38456411

RESUMO

Detecting scandium (Sc) with high selectivity and sensitivity is a challenging task due to its chemical similarity to other rare earth ions. Our findings show that the fluorescence of the complex fluorescent indicator calcein (CL) is quenched under acidic conditions (pH = 2), and Sc3+ strongly inhibits this process. The results demonstrate that CL forms multimers and precipitates out of the solution under acidic conditions, while Sc3+ causes a significant decrease in the scattering intensity of the solution. Additional experiments revealed that the strong Lewis acid nature of Sc3+ complexes with the carboxyl groups of CL leads to increased dispersion of CL even under acidic conditions, thus enhancing its absorption and fluorescence. The complexation ratio of Sc3+ and CL was investigated through spectral titrations and theoretical calculations. The interaction between Sc3+ and CL is the strongest among rare earth and common metal ions due to the smallest ionic radius, resulting in high selectivity. The fluorescence turn-on strategy had a linear range of 0.04 to 2.25 µM under optimal conditions, with a detection limit of 20 nM for Sc3+. The combination of 3D printing and a smartphone program allows for portable on-site analysis of Sc3+. Mineral and water samples were used to demonstrate the potential of this strategy for the rapid, selective, and sensitive analysis of low levels of Sc3+.

3.
Talanta ; 272: 125833, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38430867

RESUMO

Iodine is essential for human growth and can enter the body through food, water, and air. Analyzing its presence in the environment is crucial for ensuring healthy human development. However, current large-scale instruments have limitations in the field analysis of iodine. Herein, a miniaturized purge and trap point discharge microplasma optical emission spectrometric (P&T-µPD-OES) device was developed for the field analysis of iodine in water. Volatile iodine molecules were produced from total inorganic iodine (TII) through a basic redox reaction under acidic conditions, then the purge and trap module effectively separated and preconcentrated iodine molecules. The iodine molecules were subsequently atomized and excited by the integrated point discharge microplasma and an iodine atomic emission line at 206.24 nm was monitored by the spectrometer. Under optimal conditions, this proposed method had a detection limit of 16.2 µg L-1 for iodine and a precision better than 4.8%. Besides, the accuracy of the portable device was validated by successful analysis of surface and groundwater samples and a comparison of the mass spectrometry method. This proposed portable, low-power device is expected to support rapid access to iodine levels and distribution in water.

4.
Int J Med Inform ; 181: 105279, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37977054

RESUMO

BACKGROUND: Prostate cancer is currently the second most prevalent cancer among men. Accurate diagnosis of prostate cancer can provide effective treatment for patients and greatly reduce mortality. The current medical imaging tools for screening prostate cancer are mainly MRI, CT and ultrasound. In the past 20 years, these medical imaging methods have made great progress with machine learning, especially the rise of deep learning has led to a wider application of artificial intelligence in the use of image-assisted diagnosis of prostate cancer. METHOD: This review collected medical image processing methods, prostate and prostate cancer on MR images, CT images, and ultrasound images through search engines such as web of science, PubMed, and Google Scholar, including image pre-processing methods, segmentation of prostate gland on medical images, registration between prostate gland on different modal images, detection of prostate cancer lesions on the prostate. CONCLUSION: Through these collated papers, it is found that the current research on the diagnosis and staging of prostate cancer using machine learning and deep learning is in its infancy, and most of the existing studies are on the diagnosis of prostate cancer and classification of lesions, and the accuracy is low, with the best results having an accuracy of less than 0.95. There are fewer studies on staging. The research is mainly focused on MR images and much less on CT images, ultrasound images. DISCUSSION: Machine learning and deep learning combined with medical imaging have a broad application prospect for the diagnosis and staging of prostate cancer, but the research in this area still has more room for development.


Assuntos
Inteligência Artificial , Neoplasias da Próstata , Masculino , Humanos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Próstata/diagnóstico por imagem , Próstata/patologia , Aprendizado de Máquina , Imageamento por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos
5.
Int Immunopharmacol ; 124(Pt A): 110879, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37713785

RESUMO

BACKGROUND: Ovarian cancer (OC) is one of the most common gynecological malignant cancers. Our previous work confirmed that circNFIX acted as an oncogene in OC, which could promote malignant proliferation, metastasis and angiogenesis. However, the role and mechanism of circNFIX in OC immune escape remain unclear. METHODS: The RNA and protein levels were determined by qRT-PCR and western blot assays. The malignant phenotypes were tested by cell count kit-8, EdU staining, flow cytometry and transwell assays. The immune cytokines levels were measured by ELISA analysis. Molecular interactions were verified employing RNA immunoprecipitation, meRIP and dual luciferase methods. In vivo validation was performed by xenograft tumor and lung metastasis model. Hematoxylin & eosin and immunohistochemistry staining were used to observe the pathological changes. RESULTS: The levels of circNFIX, PD-L1, and IL-6R were upregulated in OC tissues and cell lines, while miR-647 was downregulated. Functional assays showed that loss of circNFIX suppressed the growth, metastasis and immune escape of OC cells both in vitro and in vivo. On the molecular level, the m6A modification of circNFIX was elevated in OC cells, and its expression was positively correlated to m6A modification and depended on IGF2BP1 âˆ¼ 3 recognition. Moreover, circNFIX acted as a competing endogenous RNA for miR-647 to upregulate IL-6R expression, thereby activating JAK/STAT3 signaling and elevating PD-L1 expression. Rescue assays revealed that co-silencing of miR-647 reversed the antitumor effects of circNFIX knockdown on cell proliferation, metastasis and immune escape of OC cells. CONCLUSION: This study provided a comprehensive understanding of the molecular mechanism about circNFIX in OC, demonstrating m6A activated-circNFIX accelerated OC development and immune escape via regulating miR-647/IL-6R/PD-L1 pathway.


Assuntos
MicroRNAs , Neoplasias Ovarianas , RNA Circular , Feminino , Humanos , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Janus Quinase 1/genética , Janus Quinase 1/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Ovarianas/metabolismo , Transdução de Sinais , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Receptores de Interleucina-6/metabolismo
6.
Plants (Basel) ; 12(15)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37570944

RESUMO

Growth regulatory factors (GRF) are plant-specific transcription factors that play pivotal roles in growth and various abiotic stresses regulation. However, adaptive evolution of GRF gene family in land plants are still being elucidated. Here, we performed the evolutionary and expression analysis of GRF gene family from seven representative species. Extensive phylogenetic analyses and gene structure analysis revealed that the number of genes, QLQ domain and WRC domain identified in higher plants was significantly greater than those identified in lower plants. Besides, dispersed duplication and WGD/segmental duplication effectively promoted expansion of the GRF gene family. The expression patterns of GRF gene family and target genes were found in multiple floral organs and abundant in actively growing tissues. They were also found to be particularly expressed in response to various abiotic stresses, with stress-related elements in promoters, implying potential roles in floral development and abiotic stress. Our analysis in GRF gene family interaction network indicated the similar results that GRFs resist to abiotic stresses with the cooperation of other transcription factors like GIFs. This study provides insights into evolution in the GRF gene family, together with expression patterns valuable for future functional researches of plant abiotic stress biology.

7.
Ecotoxicol Environ Saf ; 262: 115166, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37348213

RESUMO

The widespread heavy metal contamination of agricultural soils poses an enormous challenge to food safety. To evaluate the Cd immobilization potential of vermicompost combined with modified shell powder (VMSP) on Cd-contaminated soil, batch adsorption tests and field experiments were conducted. First, the Cd2+ removal characteristics and adsorption mechanisms of vermicompost (V), vermicompost combined with shell powder (VSP), and VMSP in an aqueous solution were investigated by batch tests. Then, 3 kg·m2 V, VSP, and VMSP doses were applied to Cd-contaminated farmland soils as soil amendments to plant green garlic (Allium sativum L.) and investigate their Cd immobilization effects in Cd-contaminated soils. Batch adsorption tests showed that VMSP was most effective for Cd2+ removal, with adsorption rates as high as 85.7-99.79% and desorption rates of approximately 1.25-1.34%. Combining further characterization analysis of VMSP, it was demonstrated that the adsorption mechanism of Cd2+ was monolayer chemisorption, mainly involving the complexation reaction of Cd2+ with organic functional groups and the precipitation reaction of Cd2+ with mineral elements. The field experiment showed that adding V, VSP, and VMSP effectively inhibited the enrichment of Cd in green garlic, and the Cd content was reduced by 42.18%, 46.88%, and 68.75%, respectively. However, only the Cd content of green garlic treated with VMSP was lower than the national standard for food safety in China (Cd≤ 0.2 mg·kg-1). V, VSP, and VMSP additions improved soil fertility and reduced Cd bioavailability in the soil by 15.5%, 18.9%, and 36.3%, respectively. In addition, V, VSP, and VMSP addition increased bacterial diversity and improved bacterial communities and functions in the soil by improving basic soil properties and reducing Cd-related toxicity. The results indicated that VMSP is a promising amendment for Cd immobilization in Cd-contaminated farmland soils.

8.
J Biol Chem ; 299(7): 104840, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37209819

RESUMO

Adenosine-to-inosine RNA editing is catalyzed by nuclear adenosine deaminase acting on RNA 1 (ADAR1) p110 and ADAR2, and cytoplasmic ADAR1 p150 in mammals, all of which recognize dsRNAs as targets. RNA editing occurs in some coding regions, which alters protein functions by exchanging amino acid sequences, and is therefore physiologically significant. In general, such coding sites are edited by ADAR1 p110 and ADAR2 before splicing, given that the corresponding exon forms a dsRNA structure with an adjacent intron. We previously found that RNA editing at two coding sites of antizyme inhibitor 1 (AZIN1) is sustained in Adar1 p110/Aadr2 double KO mice. However, the molecular mechanisms underlying RNA editing of AZIN1 remain unknown. Here, we showed that Azin1 editing levels were increased upon type I interferon treatment, which activated Adar1 p150 transcription, in mouse Raw 264.7 cells. Azin1 RNA editing was observed in mature mRNA but not precursor mRNA. Furthermore, we revealed that the two coding sites were editable only by ADAR1 p150 in both mouse Raw 264.7 and human embryonic kidney 293T cells. This unique editing was achieved by forming a dsRNA structure with a downstream exon after splicing, and the intervening intron suppressed RNA editing. Therefore, deletion of a nuclear export signal from ADAR1 p150, shifting its localization to the nucleus, decreased Azin1 editing levels. Finally, we demonstrated that Azin1 RNA editing was completely absent in Adar1 p150 KO mice. Thus, these findings indicate that RNA editing of AZIN1 coding sites is exceptionally catalyzed by ADAR1 p150 after splicing.


Assuntos
Adenosina Desaminase , Proteínas de Transporte , Edição de RNA , Animais , Humanos , Camundongos , Adenosina Desaminase/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Catálise , Edição de RNA/efeitos dos fármacos , Edição de RNA/genética , RNA de Cadeia Dupla/genética , RNA Mensageiro/metabolismo , Células HEK293 , Camundongos Knockout , Células RAW 264.7 , Interferons/farmacologia , Transporte Proteico
9.
Kaohsiung J Med Sci ; 39(1): 26-39, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36448712

RESUMO

Ovarian cancer (OC) is a gynecological cancer with high mortality. OC-derived exosomal circRNAs can regulate angiogenesis. This study aims to explore the role and mechanism of exosomal circRNA nuclear factor I X (CircNFIX) derived from OC cells in angiogenesis. Quantitative real-time polymerase chain reaction was employed to evaluate the levels of circNFIX, miR-518a-3p, and tripartite motif protein 44 (TRIM44) in OC and adjacent tissues. Exosomes from the ovarian surface epithelial cell (HOSEpiC) and OC cells (SKOV3 or OVCAR3) were isolated by differential centrifugation. Exosomes were cocultured with the human umbilical vein endothelial cells (HUVECs). The angiogenesis capacity was analyzed by Tube formation assay. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and Transwell assays were used to determine the cell viability and migration ability. The dual-luciferase report, RNA immunoprecipitation (RIP), and RNA pull-down assays were applied to validate the gene's interaction. CircNFIX and TRIM44 expression were higher and miR-518a-3p was lower in OC tissues than in the adjacent tissues. Upregulated circNFIX and TRIM44 were significantly correlated with the tumor size and International Federation of Gynecology and Obstetrics (FIGO) stage of OC patients. HUVECs treated OC-derived exosomes had higher proliferation, migration, and angiogenesis capacities than the control group. While OC-derived exosomal circNFIX silencing restrained HUVECs' proliferation, migration, and angiogenesis, compared with the OC-derived exosomes group. OC-derived exosomal circNFIX positively regulated TRIM44 expression by targeting miR-518a-3p in HUVECs. OC-derived exosomal circNFIX promoted angiogenesis by regulating the Janus-activated kinase/signal transducer and activator of transcription 1 (JAK/STAT1) pathway via miR-518a-3p/TRIM44 axis in HUVECs.


Assuntos
MicroRNAs , Neoplasias Ovarianas , Humanos , Feminino , MicroRNAs/genética , MicroRNAs/metabolismo , Apoptose , Proteínas com Motivo Tripartido/metabolismo , Neoplasias Ovarianas/metabolismo , Linhagem Celular Tumoral , Células Endoteliais da Veia Umbilical Humana/metabolismo , Proliferação de Células/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo
10.
Kaohsiung J Med Sci ; 39(3): 234-243, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36495291

RESUMO

We aimed to study the regulatory roles and mechanism of circular nuclear factor IX (circNFIX) in cancer growth and stemness properties of ovarian cancer (OC). CircNFIX and SH3RF3 levels in OC tissues and cells were tested by quantitative real-time PCR. RNase R treatment quantified circNFIX RNA stability. Molecular interaction among circNFIX, LIN28B, and SH3RF3 was predicted by bioinformatics software and validated through RNA immunoprecipitation (RIP) assay. The gain- or loss-experiments of circNFIX on capabilities of metastasis and stemness in vitro were assessed using Cell Counting Kit-8, Transwell, western blot, and sphere-formation assays. CircNFIX and SH3RF3 were markedly elevated in OC tissues and OC cells. Knocking down circNFIX repressed the proliferation, migration, invasion, and stemness properties of A2780 and SKOV3 cells. The RIP assay verified the direct binding relationship between LIN28B, circNFIX, and SH3RF3. Additionally, overexpression of circNFIX elevated the SH3RF3 expression, while this effect was reversed by LIN28B silence. Rescue experiments demonstrated that the overexpression of SH3RF3 reversed the knockdown of circNFIX on OC cells' proliferation, metastasis, and stemness properties. CircNFIX improved the mRNA stability and translation of SH3RF3 via recruiting LIN28B, thus promoting the proliferation, invasion, and stemness properties of OC cells in vitro.


Assuntos
MicroRNAs , Neoplasias Ovarianas , Humanos , Feminino , Neoplasias Ovarianas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , MicroRNAs/genética , Regulação Neoplásica da Expressão Gênica , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ubiquitina-Proteína Ligases/genética
11.
Nucleic Acids Res ; 50(19): 10896-10913, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-35801907

RESUMO

Post-transcriptional RNA modifications critically regulate various biological processes. N4-acetylcytidine (ac4C) is an epi-transcriptome, which is highly conserved in all species. However, the in vivo physiological functions and regulatory mechanisms of ac4C remain poorly understood, particularly in mammals. In this study, we demonstrate that the only known ac4C writer, N-acetyltransferase 10 (NAT10), plays an essential role in male reproduction. We identified the occurrence of ac4C in the mRNAs of mouse tissues and showed that ac4C undergoes dynamic changes during spermatogenesis. Germ cell-specific ablation of Nat10 severely inhibits meiotic entry and leads to defects in homologous chromosome synapsis, meiotic recombination and repair of DNA double-strand breaks during meiosis. Transcriptomic profiling revealed dysregulation of functional genes in meiotic prophase I after Nat10 deletion. These findings highlight the crucial physiological functions of ac4C modifications in male spermatogenesis and expand our understanding of its role in the regulation of specific physiological processes in vivo.


Assuntos
Citidina , Meiose , Masculino , Camundongos , Animais , Meiose/genética , Citidina/genética , Pareamento Cromossômico , Células Germinativas , Mamíferos
12.
Cell Mol Life Sci ; 79(2): 92, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35072788

RESUMO

Putative RNA-binding proteins (RBPs), zygote arrested-1 (ZAR1), and ZAR2 (also known as ZAR1L), have been identified as maternal factors that mainly function in oogenesis and embryogenesis. Despite divergence in their spatio-temporal expression among species, the CxxC structure of the C-terminus of ZAR proteins is highly conserved and is reported to be the functional domain for the activity of the RBPs of ZAR proteins. In oocytes from Xenopus laevis and zebrafish, ZAR proteins have been reported to bind to maternal transcripts and inhibit translation in immature growing oocytes, whereas in fully grown mouse oocytes, they promote the translation during meiotic maturation. Thus, ZAR1 and ZAR2 may be required for the maternal-to-zygotic transition by stabilizing the maternal transcriptome in oocytes with partial functional redundancy. In addition, recent studies have suggested non-ovarian expression and function of ZAR proteins, particularly their involvement in tumorigenesis. ZAR proteins are potentially associated with tumor suppressors and can serve as epigenetically inactivated cancer biomarkers. In this review, studies on Zar1/2 are systematically summarized, and some issues that require discussion and further investigation are introduced as perspectives.


Assuntos
Proteínas do Ovo/metabolismo , Fertilidade , Oogênese , Proteínas Supressoras de Tumor/metabolismo , Animais , Proteínas do Ovo/genética , Feminino , Humanos , Proteínas Supressoras de Tumor/genética
13.
Front Cell Dev Biol ; 9: 661155, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33834027

RESUMO

Bisphenol A (BPA) is one of the ubiquitous environmental endocrine disruptors (EEDs). Previous studies have shown that the reproduction toxicity of BPA could cause severe effects on the mammal oocytes and disturb the quality of mature oocytes. However, the toxic effects of BPA on the organelles of mouse oocytes have not been reported. In this study, to investigate whether BPA can be toxic to the organelles, we used different concentrations of BPA (50, 100, and 200 µM) to culture mouse oocytes in vitro. The results showed that 100 µM BPA exposure could significantly decrease the developmental capacity of oocytes. Then, we used the immunofluorescence staining, confocal microscopy, and western blotting to investigate the toxic effects of BPA on the organelles. The results revealed that mitochondrial dysfunction is manifested by abnormal distribution and decreased mitochondrial membrane potential. Moreover, the endoplasmic reticulum (ER) is abnormally distributed which is accompanied by ER stress showing increased expression of GRP78. For the Golgi apparatus, BPA-exposed dose not disorder the Golgi apparatus distribution but caused abnormal structure of Golgi apparatus, which is manifested by the decrease of GM130 protein expression. Moreover, we also found that BPA-exposed led to the damage of lysosome, which were shown by the increase of LAMP2 protein expression. Collectively, our findings demonstrated that the exposure of BPA could damage the normal function of the organelles, which may explain the reduced maturation quality of oocytes.

14.
Inorg Chem ; 58(9): 6000-6007, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31021616

RESUMO

Two transition-metal-substituted compounds K10H10{[Co(H2O)2]2[Co(H2O)3]2(Ge4W36O130)}·32H2O (1Co) and K10H10{[Ni(H2O)2]2[Ni(H2O)3]2(Ge4W36O130)}·32H2O (2Ni), have been successfully synthesized, both of which consist of the S-shaped tetrameric structure {Ge4W36} constructed from trivacant Keggin-type germanotungstate precursor K8Na2[ A-α-GeW9O34]·25H2O. These compounds were characterized by single crystal X-ray diffraction crystallography, X-ray powder diffraction (XRD), Raman spectra, thermogravimetric analysis (TGA), electrochemistry, and IR spectra. In addition, the UV spectra and the electrospray-ionization mass spectra (ESI-MS) were employed to investigated the stable pH value range of 1Co and 2Ni in aqueous solution.


Assuntos
Cobalto/química , Germânio/química , Níquel/química , Compostos de Tungstênio/química , Ânions/síntese química , Ânions/química , Cristalografia por Raios X , Modelos Moleculares , Difração de Pó , Compostos de Tungstênio/síntese química , Difração de Raios X
16.
Mol Cancer ; 17(1): 163, 2018 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-30466461

RESUMO

tRNA-derived small non-coding RNAs (tsncRNAs), a class of newly defined small non-coding RNA, have been considered to be involved in various cellular biological processes through regulating gene expression at both transcriptional and post-transcriptional level. However, the presence of circulating tsncRNAs and their diagnostic potential is largely unclear. In this study, we investigate the serum-derived public transcriptome data from ovarian tumor patients and non-cancer controls, and find that circulating tsncRNAs cover a high proportion of total small RNA and are non-random degradation products in serum (ranging from 2.5-29.4%), which are enriched in several specific types of related tRNA (e.g., Gly-tRNA). Particularly, four tsncRNAs are differentially expressed in serum from cancer patients compared to those from healthy controls, and can predict abnormal cell proliferation with high accuracy. Our results reveal the ubiquitous presence of circulating tsncRNAs in serum, and diagnostic potential of specific tsncRNAs for ovarian tumor.


Assuntos
Biomarcadores Tumorais , Ácidos Nucleicos Livres , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/genética , Pequeno RNA não Traduzido , RNA de Transferência , Feminino , Humanos , Neoplasias Ovarianas/sangue , Prognóstico , Curva ROC
17.
Nanomaterials (Basel) ; 8(10)2018 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-30274166

RESUMO

An auxiliary electrode introduced in traditional spinneret electrospinning is an effective and powerful technique to improve the production rate of nanofibers. In this work, the effects of the arrangement of auxiliary electrode, applied voltage, injection speed, and the distance between the electrode tip and the spinneret tip (ESD) on the jet number and the morphology of polyvinyl alcohol (PVA) nanofibers were investigated systematically. The results showed that the number of jets firstly increased and then decreased with the increase of applied voltage and ESD, respectively, while increasing with the injection speed in both the auxiliary electrode in the vertical position and parallel position. The average nanofiber diameter decreased with increasing of applied voltage and injection speed, but decreasing in ESD in these two positions. The numerical simulation results revealed that the auxiliary electrode primarily influenced the electric field intensity in the spinning area. This work provides a deep understanding of multiple jets in electrospinning.

18.
Polymers (Basel) ; 10(12)2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30961235

RESUMO

Porous polym er materials have received great interest in both academic and industrial fields due to their wide range of applications. In this work, a porous polyamide 6 (PA6) material was prepared by a facile solution foaming strategy. In this approach, a sodium carbonate (SC) aqueous solution acted as the foaming agent that reacted with formic acid (FA), generating CO2 and causing phase separation of polyamide (PA). The influence of the PA/FA solution concentration and Na2CO3 concentration on the microstructures and physical properties of prepared PA foams were investigated, respectively. PA foams showed a hierarchical porous structure along the foaming direction. The mean pore dimension ranged from hundreds of nanometers to several microns. Low amounts of sodium salt generated from a neutralization reaction played an important role of heterogeneous nucleation, which increased the crystalline degree of PA foams. The porous PA materials exhibited low thermal conductivity, high crystallinity and good mechanical properties. The novel strategy in this work could produce PA foams on a large scale for potential engineering applications.

19.
Polymers (Basel) ; 10(6)2018 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-30966606

RESUMO

Multiple jets ejection in electrospinning has been a major approach to achieving a high production rate of ultrafine fibers, also known as nanofibers. This work studies the effect of solution parameters-including dielectric constant, polarity, conductivity and surface tension-on the jet number and jet evolution in the auxiliary electrode electrospinning approach. The results show that it is easier to generate 2⁻6 jets with short stable jet length (1.7⁻6.9 mm) under low voltage (5.03⁻7.13 kV) when solutions have higher dielectric constant (32.2⁻78.6) and larger surface tension (31.8⁻41.29 mN/m). The influence of solution properties on stable jet length and the influence of applied voltage to produce multiple jets are discussed in detail. This work provides a new perspective for understanding jet evolution and mass production of nanofibers in electrospinning.

20.
Ann Transplant ; 22: 75-82, 2017 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-28184034

RESUMO

BACKGROUND Ischemia-reperfusion injury (IRI) is a clinically common pathologic process defined as the inability to improve neuronal function. This study aimed to investigate the pathological mechanism of IRI and to explore effects of hyperbaric oxygenation (HBO) on autophagy and inflammatory response in IRI. MATERIAL AND METHODS Ninety Sprague-Dawley (SD) rats were randomly divided into a Sham group, a kidney transplant group (Trans), and a kidney transplant plus HBO treatment group (Trans+HBO). The kidney was harvested from the donor and transplanted to recipient rats according to a previously reported study. Rats were anesthetized using pentobarbital-natrium, and the kidney was resected and fixed in 4% paraformaldehyde. Serum creatinine (Scr) was detected using an automatic biochemical analyzer. The interleukin-6 (IL-6) level was assessed using enzyme-linked immunosorbent assay (ELISA). LC-3 was examined using indirect immunofluorescence assay and immunochemistry assay. LC-3 mRNA levels were analyzed using real-time PCR (RT-PCR). RESULTS The kidney transplant IRI model was successfully established. Scr and IL-6 levels were significantly increased in the Trans group (P<0.05). HBO significantly enhanced Scr and IL-6 levels. Scr was positively correlated with IL-6 levels (r-0.607, P<0.05). HBO increased LC-3 protein and mRNA expression in kidney-transplanted rats compared to the Sham and Trans group (P<0.05). Moreover, immunofluorescence assay also showed that LC-3 protein mainly distributes along renal tubular epithelial cells in a linear manner. CONCLUSIONS Autophagy dysfunction and inflammatory response after renal transplantation play important roles in processes of IRI. HBO treatment protects against the renal injury of IRI in renal tissues at the early stage, which may be triggered by the IL-6 pathway.


Assuntos
Autofagia/fisiologia , Oxigenoterapia Hiperbárica , Inflamação/patologia , Rim/irrigação sanguínea , Traumatismo por Reperfusão/prevenção & controle , Animais , Creatinina/sangue , Inflamação/sangue , Interleucina-6/sangue , Rim/patologia , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologia
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