126 research outputs found

    Factors impacting the benefits and pathogenicity of Th17 cells in the tumor microenvironment

    Get PDF
    Tumor development is closely associated with a complex tumor microenvironment, which is composed of tumor cells, blood vessels, tumor stromal cells, infiltrating immune cells, and associated effector molecules. T helper type 17 (Th17) cells, which are a subset of CD4+ T cells and are renowned for their ability to combat bacterial and fungal infections and mediate inflammatory responses, exhibit context-dependent effector functions. Within the tumor microenvironment, different molecular signals regulate the proliferation, differentiation, metabolic reprogramming, and phenotypic conversion of Th17 cells. Consequently, Th17 cells exert dual effects on tumor progression and can promote or inhibit tumor growth. This review aimed to investigate the impact of various alterations in the tumor microenvironment on the antitumor and protumor effects of Th17 cells to provide valuable clues for the exploration of additional tumor immunotherapy strategies

    Strain sensing characterization of polymer optical fibre Bragg gratings

    Full text link
    Static tensile strain is applied to polymer optical fibre Bragg gratings for the strain sensing characterization. Experimental results indicate that the strain coefficient of polymer fiber Bragg gratings is larger that that of silica fibre Bragg gratings. It is also demonstrated the large strain sensing range with good reproducibility, reversibility and repeatability is achieved. As a result, the study shows the great potential of polymer fibre Bragg gratings in the fibre strain sensing applications

    Polymer fiber gragg gratings with 28-dB transmission rejection

    Full text link
    Polymer fiber Bragg gratings (FBGs) with 28-dB transmission rejection and a line width less than 0.5 nm has been achieved for the first time. This result is achieved based on the systematic investigation of growth dynamics of polymer FBGs. We have observed that the growth of polymer FBGs bears some similarities to that of silica FBGs. This work links the mechanism of polymer fiber gratings formation to silica fiber grating and helps to gain better understanding of polymer fiber grating formation proces

    Thermal characterization of type I and Type II polymer optical fiber Bragg gratings

    Full text link
    Two different types of POF gratings, named as Type I and Type I POF gratings, have been distinctively identified in our previous report. Thermal characterization for Type I and Type II POF gratings is carried out in this paper. Our investigation shows that the thermal sensitivity for Type I and Type II POF gratings are the same, while Type II are more thermally stable than Type I POF gratings. Furthermore, it is also demonstrated that POF gratings have much better thermal tunability and higher thermal sensitivity than that of silica fiber gratings

    A simple strain sensor using polymer fibre Bragg grating and long period fibre grating

    Full text link
    We develop a simple strain sensor using polymer optical fibre Bragg grating and long period fibre grating. The sensor head is formed by a polymer optical fiber Bragg grating. A long period fibre grating is used for strain related wavelength shift demodulation. This particular combination of two quite different gratings could offer very large dynamic, up to tens of thousands micro-strains, for strain sensing. The preliminary experimental results have demonstrated that this sensing scheme provides good linearity, high resolution and large dynamic range

    A flow cytometer based protocol for quantitative analysis of bloom-forming cyanobacteria (Microcystis) in lake sediments

    Get PDF
    A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium

    Carnosic Acid Mitigates Early Brain Injury After Subarachnoid Hemorrhage: Possible Involvement of the SIRT1/p66shc Signaling Pathway

    Get PDF
    Carnosic acid (CA) has been reported to exhibit a variety of bioactivities including antioxidation, neuroprotection, and anti-inflammation; however, the impact of CA on subarachnoid hemorrhage (SAH) has never been elucidated. The current study was undertaken to explore the role of CA in early brain injury (EBI) secondary to SAH and the underlying mechanisms. Adult male Sprague-Dawley rats were perforated to mimic a clinical aneurysm with SAH. CA or vehicle was administered intravenously immediately after the SAH occurred. Mortality, SAH grade, neurologic function scores, brain water content, Evans blue extravasation, and the levels of reactive oxygen species (ROS) levels in the ipsilateral cortex were determined 24 h after the SAH occurred. Western blot, immunofluorescence, Fluoro-Jade C (FJC) and TUNEL staining were also performed. Our results showed that CA decreased ROS levels, alleviated brain edema and blood-brain barrier permeability, reduced neuronal cell death, and promoted neurologic function improvement. To probe into the potential mechanisms. We showed that CA increased SIRT1, MnSOD, and Bcl-2 expression, as well as decreased p66shc, Bax, and cleaved caspase-3 expression. Interestingly, sirtinol, a selective inhibitor of SIRT1, abolished the anti-apoptotic effects of CA. Taken together, these data revealed that CA has a neuroprotective role in EBI secondary to SAH. The potential mechanism may involve suppression of neuronal apoptosis through the SIRT1/p66shc signaling pathway. CA may provide a promising therapeutic regimen for management of SAH

    The Lysosomal v-ATPase-Ragulator Complex Is a Common Activator for AMPK and mTORC1, Acting as a Switch between Catabolism and Anabolism

    Get PDF
    林圣彩教授课题组长期致力于细胞信号转导的研究。近年来,该课题组潜心研究,不断攻关,取得了一系列重大成果,如揭示细胞如何应对生长因子缺乏的内在机理,发现了细胞自噬“路线图”、还发现了细胞如何感应“饥饿”信号AMP的信号传导通路等。其中,“发现细胞自噬‘路线图’”成果曾登上《科学》杂志,并入选2012年度“中国科学十大进展”。AMPK and mTOR play principal roles in governing metabolic programs; however, mechanisms underlying the coordination of the two inversely regulated kinases remain unclear. In this study we found, most surprisingly, that the late endosomal/lysosomal protein complex v-ATPase-Ragulator, essential for activation of mTORC1, is also required for AMPK activation. We also uncovered that AMPK is a residential protein of late endosome/lysosome. Under glucose starvation, the v-ATPase-Ragulator complex is accessible to AXIN/LKB1 for AMPK activation. Concurrently, the guanine nucleotide exchange factor (GEF) activity of Ragulator toward RAG is inhibited by AXIN, causing dissociation from endosome and inactivation of mTORC1. We have thus revealed that the v-ATPase-Ragulator complex is also an initiating sensor for energy stress and meanwhile serves as an endosomal docking site for LKB1-mediated AMPK activation by forming the v-ATPase-Ragulator-AXIN/LKB1-AMPK complex, thereby providing a switch between catabolism and anabolism. Our current study also emphasizes a general role of late endosome/lysosome in controlling metabolic programs
    corecore