| 1. |
|
|
| 2. |
- Beal, Jacob, et al.
(author)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 3. |
- Cui, Xing-Mei, et al.
(author)
-
Unique UV-Erasable In-Ga-Zn-O TFT Memory With Self-Assembled Pt Nanocrystals
- 2013
-
In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 34:8, s. 1011-1013
-
Journal article (peer-reviewed)abstract
- Semiconducting amorphous indium-gallium-zinc oxide (a-IGZO) films are integrated with an Al2O3/Pt-nanocrystals/ Al2O3 gate-stack to form UV-erasable thin-film transistor (TFT) memory. The threshold voltage (V-th), sub-threshold swing, I-ON/I-OFF ratio, and effective electron mobility of the fabricated devices are 2.1 V, 0.39 V/decade, similar to 10(6), and 8.4 cm(2)/V.s, respectively. A positive V-th shift of 2.25 V is achieved after 1-ms programming at 10 V-th, whereas a negative V-th shift as large as 3.48 V is attained after 5-s UV erasing. In addition, a 10-year memory window of 2.56 V is extrapolated at room temperature. This high-performance a-IGZO TFT memory is suitable for optical touch-panel applications.
|
|
| 4. |
- Ding, Mei, et al.
(author)
-
Regulation of hypoxia-inducible factor 2-a is essential for integrity of the glomerular barrier
- 2013
-
In: American Journal of Physiology - Renal Physiology. - : American Physiological Society. - 0363-6127 .- 1522-1466 .- 1931-857X. ; 304:1, s. F120-F126
-
Journal article (peer-reviewed)abstract
- Deletion of the von Hippel-Lindau tumor suppressor (Vhl) gene from renal podocytes of mice (podVhl KO) leads to rapidly progressive glomerulonephritis (RPGN), a clinical syndrome characterized by rapid loss of renal function and crescents on renal biopsy. Genomic profiling of glomeruli isolated from podVhl knockout (KO) mice and from patients with RPGN identified a fingerprint of genes regulated by hypoxia-inducible factors (HIF), important substrates of the product of the VHL gene. Here, we show that stabilization of Hifs in podocytes is both required and sufficient for the glomerular phenotype observed in podVhl KO mice. Genetic deletion of the obligate dimerization partner Arnt/Hif1b that is essential for Hif transcriptional function rescues the phenotype. Conversely, stabilization of HIF2A alone in podocytes results in crescentic glomerular disease. Together, our results show that the Hif pathway and Hif2a in particular are key players in maintenance of the glomerular barrier.
|
|
| 5. |
- Ding, Mei, 1965
(author)
-
Role of intermediate filaments and expression of GFAP and S-100 in astrocytes
- 2000
-
Doctoral thesis (other academic/artistic)abstract
- Astrocytes participate in a variety of important physiologic and pathologic processes in the central nervous system (CNS). One of the most remarkable characteristics of astrocytes is their vigorous response to CNS injuries. Reactive astrocytosis is characterized by increased production of intermediate filament (IF) proteins, such as glial fibrillary acidic protein (GFAP) and vimentin. Such conditions also involve the overexpression of a number of neurotrophic/neuroprotective factors. These alterations contribute significantly to the pathogenesis of CNS injuries, i.e., after ischemia, trauma, seizures and hypoxia. The S-100 protein, which is abundant in astrocytes, has been shown to exert neurotrophic effects. However, only a few studies on the involvement of S-100 has been reported in neurodegenerative disorders. With regard to IF proteins, the lack of knowledge about the function of astrocytic intermediate filaments in normal cells precludes the understanding of the functional implications of certain cytoskeletal changes in reactive astrocytes. The thesis aims to reach a better understanding of the functions of S-100, GFAP and vimentin. An animal model for temporal lobe epilepsy induced by systemic kainic acid (KA) administration and primary cultures of astrocytes prepared from mice lacking GFAP and /or vimentin were used.The immunochemical results show that systemic KA administration induced a reactive gliosis as revealed by increased GFAP content in the hippocampus and the amygdala/pyriform cortex which was preceded by a decrease in NSE (an indication of neuronal density), while the gliosis in the frontal cerebral cortex and the striatum was not preceded by changes in NSE. These events were paralleled by a longlasting decrease in tissue levels of S-100 and a transient increase in cerebrospinal fluid levels of S-100. Immunocytochemically, the reactive astrocytes with overexpressed S-100 immunoreactivity were observed in the layers bordering the regions with a high degree of neuronal degeneration in the hippocampus 3 and 7 days after KA. Regions with a high degree of neuronal degeneration, such as the CA3 pyramidal layer and the hilus of the dentate gyrus showed a loss of both GFAP and S-100 immunoreactivity, suggesting a damage to or loss of astrocytes. S-100 immunoreactivity was also elevated at 3-7 days in a region with axonal sprouting, somewhat distant from the lesioned neurons, i.e. the inner third of molecular layer of the dentate gyrus. Together with the observation that tissue S-100 levels were increased in association with normalised/recovered NSE in the hippocampus at day 27, the present results would give support to the proposed role of S-100 as a neurotrophic factor. The importance of astrocytic IF proteins GFAP and vimentin for astrocyte function was studied by investigating primary cultures of astrocytes from GFAP-/- and/or vimentin -/- mice. A reduction in the GFAP expression led to an increase in glutamine levels of the primary cultured astrocytes. This was not dependent on the presence of vimentin. The total absence of IFs (GFAP-/-vim-/-) induced a substantial reduction of the regulatory volume decrease (RVD)-related taurine release in astrocytes. However, the stimulated taurine efflux was not significantly affected in GFAP-/- or vimentin-/- astrocytes which have decreased amount of IFs or differences in their composition. These results implicate an involvement of IFs in astrocyte volume regulation and in the control of glutamine levels. The effects of IFs may not be only a reflection of generally altered metabolism of astrocytes, since the deficiency of IFs does not alter normal functions of astrocytes with respect to glucose, ascorbate and taurine transport under normal culturing conditions.
|
|
| 6. |
|
|
| 7. |
- Ding, Mei, et al.
(author)
-
Secretome screening reveals immunomodulating functions of IFNα-7, PAP and GDF-7 on regulatory T-cells
- 2021
-
In: Scientific Reports. - : Springer Nature. - 2045-2322. ; , s. 16767-
-
Journal article (peer-reviewed)abstract
- Regulatory T cells (Tregs) are the key cells regulating peripheral autoreactive T lymphocytes. Tregs exert their function by suppressing effector T cells. Tregs have been shown to play essential roles in the control of a variety of physiological and pathological immune responses. However, Tregs are unstable and can lose the expression of FOXP3 and suppressive functions as a consequence of outer stimuli. Available literature suggests that secreted proteins regulate Treg functional states, such as differentiation, proliferation and suppressive function. Identification of secreted proteins that affect Treg cell function are highly interesting for both therapeutic and diagnostic purposes in either hyperactive or immunosuppressed populations. Here, we report a phenotypic screening of a human secretome library in human Treg cells utilising a high throughput flow cytometry technology. Screening a library of 575 secreted proteins allowed us to identify proteins stabilising or destabilising the Treg phenotype as suggested by changes in expression of Treg marker proteins FOXP3 and/or CTLA4. Four proteins including GDF-7, IL-10, PAP and IFNα-7 were identified as positive regulators that increased FOXP3 and/or CTLA4 expression. PAP is a phosphatase. A catalytic-dead version of the protein did not induce an increase in FOXP3 expression. Ten interferon proteins were identified as negative regulators that reduced the expression of both CTLA4 and FOXP3, without affecting cell viability. A transcriptomics analysis supported the differential effect on Tregs of IFNα-7 versus other IFNα proteins, indicating differences in JAK/STAT signaling. A conformational model experiment confirmed a tenfold reduction in IFNAR-mediated ISG transcription for IFNα-7 compared to IFNα-10. This further strengthened the theory of a shift in downstream messaging upon external stimulation. As a summary, we have identified four positive regulators of FOXP3 and/or CTLA4 expression. Further exploration of these Treg modulators and their method of action has the potential to aid the discovery of novel therapies for both autoimmune and infectious diseases as well as for cancer.
|
|
| 8. |
- Ding, Mei, et al.
(author)
-
Water Signatures and Their Thermal Stability in Bedded Salt for Nuclear Waste Storage: An Incoherent Inelastic Neutron Spectroscopy Study
- 2015
-
In: Environmental Science & Technology Letters. - : American Chemical Society (ACS). - 2328-8930. ; 2:11, s. 308-313
-
Journal article (peer-reviewed)abstract
- The forms of water and their thermal stability in bedded salt are crucial in determining the material's suitability for heat-generating nuclear waste storage. Here we show first-of-its-kind incoherent inelastic neutron scattering (IINS) results of bedded salts to distinguish three water environments: intergranular water molecules confined to grain boundaries, water trapped as brine in fluid inclusions, and structural water in intracrystalline hydrous minerals. Sixteen spectral lines can be distinguished unambiguously in the 0-1100 cm(-1) multiphonon and librational domain, yielding an unprecedented high resolution for a natural material. The spectral response to temperature illustrates the bimodality of the technique enabling the intergranular water component to be distinguished from that of brine, shedding light on a nearly 30-year-old problem in characterizing different forms of water in rock salt. This pioneering study shows that IINS provides insight into the cause and effect of moisture migration and its coupling to thermomechanical properties in salt formations. Our results are pertinent to subsurface energy exploration and storage, including nuclear waste storage, in salts.
|
|
| 9. |
- Ding, Yun Mei, et al.
(author)
-
Effect of social support on illness perception in patients with atrial fibrillation during “Blanking Period” : Mediating role of sense of mastery
- 2023
-
In: Nursing Open. - : Wiley. - 2054-1058. ; 10:1, s. 115-122
-
Journal article (peer-reviewed)abstract
- Aim: To explore whether sense of mastery can mediate the relationship between social support and illness perception in patients with atrial fibrillation (AF) who were at the “Blanking Period.”. Design: A cross-sectional design. Methods: 405 patients with AF who were at the “Blanking Period” in the Affiliated Hospital of Qingdao University were recruited; they completed a set of questionnaires, including the Perceived Social Support Scale, the Personal Mastery Scale and the Brief Illness Perception Questionnaire. Results: Social support and sense of mastery were both adversely connected to illness perception. The indirect effect of social support on illness perception through sense of mastery was negative, accounting for 86.04% of the total effect. Conclusion: During the “Blanking Period,” better social support and sense of mastery contribute to a positive illness perception of AF patients. Social support also can influence patients' illness perception indirectly via the mediator of sense of mastery.
|
|
| 10. |
- Jennbacken, Karin, et al.
(author)
-
Phenotypic Screen with the Human Secretome Identifies FGF16 as Inducing Proliferation of iPSC-Derived Cardiac Progenitor Cells
- 2019
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:23
-
Journal article (peer-reviewed)abstract
- Paracrine factors can induce cardiac regeneration and repair post myocardial infarction by stimulating proliferation of cardiac cells and inducing the anti-fibrotic, antiapoptotic, and immunomodulatory effects of angiogenesis. Here, we screened a human secretome library, consisting of 923 growth factors, cytokines, and proteins with unknown function, in a phenotypic screen with human cardiac progenitor cells. The primary readout in the screen was proliferation measured by nuclear count. From this screen, we identified FGF1, FGF4, FGF9, FGF16, FGF18, and seven additional proteins that induce proliferation of cardiac progenitor cells. FGF9 and FGF16 belong to the same FGF subfamily, share high sequence identity, and are described to have similar receptor preferences. Interestingly, FGF16 was shown to be specific for proliferation of cardiac progenitor cells, whereas FGF9 also proliferated human cardiac fibroblasts. Biosensor analysis of receptor preferences and quantification of receptor abundances suggested that FGF16 and FGF9 bind to different FGF receptors on the cardiac progenitor cells and cardiac fibroblasts. FGF16 also proliferated naive cardiac progenitor cells isolated from mouse heart and human cardiomyocytes derived from induced pluripotent cells. Taken together, the data suggest that FGF16 could be a suitable paracrine factor to induce cardiac regeneration and repair.
|
|
