Cell counting for in vivo flow cytometry signals with baseline drift

In biomedical research fields, the in vivo flow cytometry (IVFC) is a widely used technology which is able to monitor target cells dynamically in living animals. Although the setup of IVFC system has been well established, baseline drift is still a challenge in the process of quantifying circulating cells. Previous methods, i.e., the dynamic peak picking method, counted cells by setting a static threshold without considering the baseline drift, leading to an inaccurate cell quantification. Here, we developed a method of cell counting for IVFC data with baseline drift by interpolation fitting, automatic segmentation and wavelet-based denoising. We demonstrated its performance for IVFC signals with three types of representative baseline drift. Compared with non-baseline-correction methods, this method showed a higher sensitivity and specificity, as well as a better result in the Pearson’s correlation coefficient and the mean-squared error (MSE)

ICAM-1 depletion in the center of immunological synapses is important for calcium releasing in T-cells

T-cell activation requires the formation of the immunological synapse (IS) between a T-cell and an antigen-presenting cell (APC) to control the development of the adaptive immune response. However, calcium release, an initial signal of T-cell activation, has been found to occur before IS formation. The mechanism for triggering the calcium signaling and relationship between calcium release and IS formation remains unclear. Herein, using live-cell imaging, we found that intercellular adhesion molecule 1 (ICAM-1), an essential molecule for IS formation, accumulated and then was depleted at the center of the synapse before complete IS formation. During the process of ICAM-1 depletion, calcium was released. If ICAM-1 failed to be depleted from the center of the synapse, the sustained calcium signaling could not be induced. Moreover, depletion of ICAM-1 in ISs preferentially occurred with the contact of antigen-specific T-cells and dendritic cells (DCs). Blocking the binding of ICAM-1 and lymphocyte function-associated antigen 1 (LFA-1), ICAM-1 failed to deplete at the center of the synapse, and calcium release in T-cells decreased. In studying the mechanism of how the depletion of ICAM-1 could influence calcium release in T-cells, we found that the movement of ICAM-1 was associated with the localization of LFA-1 in the IS, which affected the localization of calcium microdomains, ORAI1 and mitochondria in IS. Therefore, the depletion of ICAM-1 in the center of the synapse is an important factor for an initial sustained calcium release in T-cells

Visualization 1: Simultaneous two-color stimulated Raman scattering microscopy by adding a fiber amplifier to a 2 ps OPO-based SRS microscope

Epi-SRS in vivo mouse skin imaging. Originally published in Optics Letters on 01 February 2017 (ol-42-3-523

Boys zone, boys talk about girls and masculinity

The morphology of a CD4+ T cell changes from round to round-flattened during the IS formation. TCR is shown red, ICAM-1 is green, and scale bar is 2 Οm. Before IS formation, TCR was uniformed on the surface of T cell. After IS formation, TCR and ICAM-1 was accumulated at the interface of T-DC

Additional file 6: Figure S4. of Morphological change of CD4+ T cell during contact with DC modulates T-cell activation by accumulation of F-actin in the immunology synapse

Ca2+ responses in CD4+ T cells were measured and presented by △F/F. (A) The shape index change and Ca2+ signal in a CD4+ T cell whose morphology changed to elongated-flattened (top panel). (B) The shape index change and Ca2+ signal of a CD4+ T cell whose morphology changed to flattened (top panel). (C) The shape index change and Ca2+ signal in a resting T cell. (A-C) Ca2+ signalling was obtained every 10-s or 40-s. (D) Average Ca2+ responses of CD4+ T cells whose morphology changed to round-flattened or to elongated-flattened. (Data are shown as mean ± s.e.m., two-tailed Student’s t-test, ***p < 0.001). (E) Ca2+ response of a CD4+ T cell after it contacted DC pulsed OVA(323–339) in the presence of the cytochalasin D or not. (F) Average Ca2+ responses were measured in CD4+ T cells during the IS formation in the presence of cytochalasin D, nocodazole, TG or cytochalasin D and TG. (mean ± s.e.m, n = 25, three independent experiments), ***P < 0.001 (two-tailed Student’s t-test). (G) Average Ca2+ responses were measured in elongated and/ or CD4+ T cells during contact with DC in the presence of the cytochalasin D or TG treatment. (mean ± s.e.m, n = 25, three independent experiments), ** P < 0.01, ***P < 0.001 (two-tailed Student’s t-test). (H) Ca2+ response in a CD4+ T cell with TG stimulation and in a CD4+ T cell forming IS with TG pretreatment. (I) Ca2+ response of a CD4+ T cell with the cytochalasin D and TG treatment and a CD4+ T cells that formed IS with the cytochalasin D and TG pretreatment

Additional file 7: Figure S5. of Morphological change of CD4+ T cell during contact with DC modulates T-cell activation by accumulation of F-actin in the immunology synapse

The distribution of microtubules in CD4+ T cells which made contact with DCs. The distribution of microtubules was measured in an elongated-flattened CD4+ T cell (top line) or a round-flattened CD4+ T cell (middle line). In the presence of the nocodazole, the distribution of microtubules was measured in a CD4+ T cell (bottom line). TCR (red) and ICAM-1 (green) are used to mark the structure of IS, respectively. Dotted white line depicts the contact boundary of CD4+ T cells and DCs. Scale bar is 2 Οm

Surface Engineering of a Nickel Oxide–Nickel Hybrid Nanoarray as a Versatile Catalyst for Both Superior Water and Urea Oxidation

Developing efficient and low-cost oxygen evolution reaction (OER) electrodes is a pressing but still challenging task for energy conversion technologies such as water electrolysis, regenerative fuel cells, and rechargeable metal–air batteries. Hence, this study reports that a nickel oxide–nickel hybrid nanoarray on nickel foam (NiO–Ni/NF) could act as a versatile anode for superior water and urea oxidation. Impressively, this anode could attain high current densities of 50 and 100 mA cm^–2 at extremely low overpotentials of 292 and 323 mV for OER, respectively. Besides, this electrode also shows excellent activity for urea oxidation with the need for just 0.28 and 0.36 V (vs SCE) to attain 10 and 100 mA cm^–2 in 1.0 M KOH with 0.33 M urea, respectively. The enhanced oxidation performance should be due to the synergistic effect of NiO and Ni, improved conductivity, and enlarged active surface area

Additional file 8: Figure S6. of Morphological change of CD4+ T cell during contact with DC modulates T-cell activation by accumulation of F-actin in the immunology synapse

The relationship between morphological changes and T-cell activation before and after IS formation. (A) Shape index changes and Ca2+ signals in a CD4+ T cell whose morphology changed to elongated-flattened (left panel). At 1,080 s, IS between CD4+ T cell and DC was formed. Before IS formation, the morphology of CD4+ T cell changed from round to elongated-flattened. At 1,680 s, the morphology of CD4+ T cell changed from elongated-flattened to round-flattened. The peak of Ca2+ signal was occurred before IS formation (at 800 s) and Ca2+ signal sustained at a low level. Images of the morphology and Ca2+ signals of the elongated-flattened T cell before and after IS formations are shown in the right panel. (B) Shape index changes and Ca2+ signals in a CD4+ T cell whose morphology changed to flattened (left panel). Images of the morphology and Ca2+ signals of the round-flattened T cell are shown in the right panel. IS between T cell and DC was formed at 560 s, when Ca2+ signal was at the highest level. The dotted white line depicts the contact boundary between the OT-II CD4+ T cells and the DCs. The calcium intensity was pseudo-colored with hues ranging from blue (low) to red (high). Ca2+ signalling was obtained every 40 s. ICAM-1 was labelled to be green. TCR was labelled to be red. After IS formation, TCR and ICAM-1 were accumulated into the IS of DC-T. Scale bar = 2 μm. (C-E) The distribution of ZAP-70, PLC-γ, PKC-θ (blue) and TCR (red) in the resting CD4+ T cell are shown in panel C to E, reseparately. Scale bar = 2 μm