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The advancement of new immunotherapies necessitates appropriate probes to monitor the presence and distribution of distinct immune cell populations. Considering the key role of CD4+T cells in regulating immunological processes, we generated novel single-domain antibodies (nanobodies, Nbs) that specifically recognize human CD4. After in depth analysis of their binding properties, recognized epitopes, and effects on T cell proliferation, activation and cytokine release, we selected CD4 Nbs that did not interfere with crucial T cell processesin vitroand converted them into immune tracers for non-invasive molecular imaging.By optical imaging, we demonstrate the ability of a high-affinity CD4-Nb to specifically visualize CD4+cellsin vivousing a xenograft model. Furthermore, time-resolved immune positron emission tomography (immunoPET) of a human CD4 knock-in mouse model showed rapid accumulation of64Cu-radiolabeled CD4-Nb in CD4+T cell-rich tissues. We propose that the CD4 Nbs presented here could serve as versatile probes for stratifying patients and monitoring individual immune responses during personalized immunotherapy in both cancer and inflammatory diseases.

Our understanding of the physical principles organizing the genome in the nucleus is limited by the lack of tools to directly exert and measure forces on interphase chromosomes in vivo and probe their material nature. Here, we present a novel approach to actively manipulate a genomic locus using controlled magnetic forces inside the nucleus of a living human cell. We observe viscoelastic displacements over microns within minutes in response to near-picoNewton forces, which are well captured by a Rouse polymer model. Our results highlight the fluidity of chromatin, with a moderate contribution of the surrounding material, revealing the minor role of crosslinks and topological effects and challenging the view that interphase chromatin is a gel-like material. Our new technology opens avenues for future research, from chromosome mechanics to genome functions.

Die Entstehung von Schadstoffen in Flugtriebwerken wird maßgeblich von den Charakteristiken des Kraftstoffsprays in der Brennkammer beeinflusst. Um Zeit und Kosten in der Brennkammerentwicklung einzusparen, ist die frühzeitige Kenntnis über das Emissionsverhalten der Brennkammer unabdinglich. Hierzu muss das Zerstäubungsverhalten der Kraftstoffdüse verstanden sein, da der Kraftstoffzerfall die Charakteristik des Sprays und somit das Brennverhalten entscheidend beeinflusst. Bei der Euler-Lagrange Methode handelt es sich um ein etabliertes Verfahren zur Vorhersage der Sprayausbreitung und -dispersion. Da hierbei die initiale Kraftstoffzerstäubung nicht direkt berechnet wird, werden adäquate Anfangsbedingungen zur Simulation der flüssigen Phase benötigt, um die Spraydispersion und damit Schadstoffemissionen zuverlässig vorhersagen zu können. Im Rahmen dieser Studie werden die Sensitivitäten der Spraydispersion auf unterschiedliche Tropfenstartbedingungen numerisch untersucht. Die Simulationen der dreidimensionalen Zerstäubergeometrie werden mittels der Euler-Lagrange Methode durchgeführt. Eine Erweiterung des Primärzerfallsmodell PAMELA [1–3] wird zur Generierung von Tropfenstartbedingungen verwendet. Numerische Spraycharakteristiken werden mit experimentellen Daten [4] verglichen. Ein starker Einfluss der initialen Tropfengeschwindigkeiten, der Rezirkulationszone, des präzedierenden Wirbelkerns und der Turbulenzmodellierung wird identifiziert. Tropfenstartbedingungen, welche eine gute Übereinstimmung mit den experimentellen Daten liefern, werden ermittelt. Diese Studie demonstriert, dass der dargestellte Ansatz geeignet ist, um die Spraydispersion in Brennkammern abzubilden.

Correction to: European Physical Journal C, vol. 77, issue 2, article number: 98.DOI: 10.1140/epjc/s10052-017-4651-x

We analyze themost recent data for the pion vector form factor in the timelike region, employing a modelindependent approach based on dispersion theory. We confirm earlier observations about the inconsistency of different modern high-precision data sets. Excluding the BaBar data, we find an updated value for the isospin-violating branching ratio B(omega -> pi(+) pi(-)) = (1.46 +/- 0.08) x 10(-2). As a side result, we also extract an improved value for the pion vector or charge radius, root < r(V)(2)> = 0.6603(5)(4) fm, where the first uncertainty is statistical as derived from the fit, while the second estimates the possible size of nonuniversal radiative corrections. In addition, we demonstrate that modern high-quality data for the decay. eta'-> pi(+) pi(-) will allow for an even improved determination of the transition strength omega -> pi(+) pi(-). Correction in: European Physical Journal C, vol. 78, issue 6, article Number: 450.DOI: 10.1140/epjc/s10052-018-5941-7

We analyze the most recent data for the pion vector form factor in the timelike region, employing a model-independent approach based on dispersion theory. We confirm earlier observations about the inconsistency of different modern high-precision data sets. Excluding the BaBar data, we find an updated value for the isospin-violating branching ratio $\mathcal{B}(��\to ��^+��^-) = (1.46\pm 0.08) \times 10^{-2}$. As a side result, we also extract an improved value for the pion vector or charge radius, $\sqrt{\langle r_V^2\rangle} = 0.6603(5)(4)\text{fm}$, where the first uncertainty is statistical as derived from the fit, while the second estimates the possible size of nonuniversal radiative corrections. In addition, we demonstrate that modern high-quality data for the decay $��' \to ��^+��^-��$ will allow for an even improved determination of the transition strength $��\to��^+��^-$., 11+2 pages, 7+1 figures; v3: erratum appended that rectifies erroneous treatment of the BaBar data

We argue that high-quality data on the reaction $e^+e^-\to ��^+��^-��$ will allow one to determine the doubly-virtual form factor $��\to ��^*��^*$ in a model-independent way with controlled accuracy. This is an important step towards a reliable evaluation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. When analyzing the existing data for $e^+e^-\to��^+��^-��$ for total energies squared $k^2>1\text{GeV}^2$, we demonstrate that the effect of the $a_2$ meson provides a natural breaking mechanism for the commonly employed factorization ansatz in the doubly-virtual form factor $F_{����^*��^*}(q^2,k^2)$. However, better data are needed to draw firm conclusions., 15 pages, 10 figures; v2: major revision - author list extended, treatment of the left-hand cut corrected, discussion and references updated; v3: version published in EPJC