These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer‐reviewed by leading experts in the field, making this an essential research companion.

International audienceThe classical model of hematopoiesis established in the mouse postulates that lymphoid cells originate from a founder population of common lymphoid progenitors. Here, using a modeling approach in humanized mice, we showed that human lymphoid development stemmed from distinct populations of CD127(-) and CD127(+) early lymphoid progenitors (ELPs). Combining molecular analyses with in vitro and in vivo functional assays, we demonstrated that CD127(-) and CD127(+) ELPs emerged independently from lympho-mono-dendritic progenitors, responded differently to Notch1 signals, underwent divergent modes of lineage restriction, and displayed both common and specific differentiation potentials. Whereas CD127(-) ELPs comprised precursors of T cells, marginal zone B cells, and natural killer (NK) and innate lymphoid cells (ILCs), CD127(+) ELPs supported production of all NK cell, ILC, and B cell populations but lacked T potential. On the basis of these results, we propose a "two-family" model of human lymphoid development that differs from the prevailing model of hematopoiesis

The far-infrared conductivity of single-wall carbon-nanotube ensembles is dominated by a broad absorption peak around 4 THz whose origin is still debated. We observe an overall depletion of this peak when the nanotubes are excited by a short visible laser pulse. This finding excludes optical absorption due to a particle-plasmon resonance and instead shows that interband transitions in tubes with an energy gap of $10 meV dominate the far-infrared conductivity. A simple model based on an ensemble of two-level systems naturally explains the weak temperature dependence of the far-infrared conductivity by the tubeto-tube variation of the chemical potential.

Intense multiterahertz fields of order megavolts per centimeter are used to coherently promote optically dark and dense paraexcitons in Cu2O from the 1s into the 2p state. The nonlinear field response of the intraexcitonic degrees of freedom is directly monitored in the time domain via ultrabroadband electro-optic sampling. The experimental results are analyzed with a microscopic many-body theory, identifying up to two internal Rabi cycles. The effects of population inversion and ponderomotive contributions are disentangled.

A well-defined scale calibration in flow cytometry can improve many aspects of data acquisition such as cytometer setup, instrument comparison and sample comparison. The theory for scale calibration was proposed by Steen over two decades ago, but it has never been put into regular use due to the lack of a widely available precision light source. The introduction of such a light source, the quantiFlash , gave this possibility. Here, we describe how this light source can be used to characterize a cytometer's PMT performance. We, therefore, characterized the instrument's response over the entire PMT voltage range. As a consequence, we propose a practical method to characterize a cytometer's signal-to-noise ratio (SNR) and dynamic range (DNR). This allows the selection of a voltage/gain corresponding to a PMT's maximum efficiency and hence the lowest electronic noise, which can help with experiment design. We further introduced a decibel (dB) scale for the presentation of SNR and DNR values. SNR and DNR are stand-alone values that allow the direct comparison of different instruments. Finally, with this method, it becomes clear that increased SNR comes at the expense of DNR and thus the limiting factor of modern cytometers is the DNR. © 2017 International Society for Advancement of Cytometry.