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T cells are required to clear infection, and T cell motion plays a role in how quickly a T cell finds its target, from initial naive T cell activation by a dendritic cell to interaction with target cells in infected tissue. To better understand how different tissue environments affect T cell motility, we compared multiple features of T cell motion including speed, persistence, turning angle, directionality, and confinement of T cells moving in multiple murine tissues using microscopy. We quantitatively analyzed naive T cell motility within the lymph node and compared motility parameters with activated CD8 T cells moving within the villi of small intestine and lung under different activation conditions. Our motility analysis found that while the speeds and the overall displacement of T cells vary within all tissues analyzed, T cells in all tissues tended to persist at the same speed. Interestingly, we found that T cells in the lung show a marked population of T cells turning at close to 180^o, while T cells in lymph nodes and villi do not exhibit this “reversing” movement. T cells in the lung also showed significantly decreased meandering ratios and increased confinement compared to T cells in lymph nodes and villi. These differences in motility patterns led to a decrease in the total volume scanned by T cells in lung compared to T cells in lymph node and villi. These results suggest that the tissue environment in which T cells move can impact the type of motility and ultimately, the efficiency of T cell search for target cells within specialized tissues such as the lung. 

The crystal structures of ligand precursor bis(imidazolium) salts 1,1′-methylenebis(3- tert -butylimidazolium) dibromide monohydrate, C 15 H 26 N 4 + ·2Br − ·H 2 O or [ t Bu NHC 2 Me][Br] 2 ·H 2 O, 1,1′-(ethane-1,2-diyl)bis(3- tert -butylimidazolium) dibromide dihydrate, C 16 H 28 N 4 + ·2Br − ·2H 2 O or [ t Bu NHC 2 Et][Br] 2 ·2H 2 O, 1,1′-methylenebis[3-(2,4,6-trimethylphenyl)imidazolium] dibromide dihydrate, C 25 H 30 N 4 2+ ·2Br − ·2H 2 O or [ Mes NHC 2 Me][Br] 2 ·2H 2 O, and 1,1′-(ethane-1,2-diyl)bis[3-(2,4,6-trimethylphenyl)imidazolium] dibromide tetrahydrate, C 26 H 32 N 4 2+ ·2Br − ·4H 2 O or [ Mes NHC 2 Et][Br] 2 ·4H 2 O, are reported. At 293 K, [ t Bu NHC 2 Me][Br] 2 ·H 2 O crystallizes in the P 2 1 / c space group, while [ t Bu NHC 2 Et][Br] 2 ·2H 2 O crystallizes in the P 2 1 / n space group at 100 K. At 112 K, [ Mes NHC 2 Me][Br] 2 ·2H 2 O crystallizes in the orthorhombic space group Pccn while [ Mes NHC 2 Et][Br] 2 ·4H 2 O crystallizes in the P 2 1 / c space group at 100 K. Bond distances and angles within the imidazolium rings are generally comparable among the four structures. All four bis(imidazolium) salts co-crystallize with one to four molecules of water. 

Abstract A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work. 

Abstract The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules.During Run 2 (2015–2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb -1 to the ATLAS experiment at a centre-of-mass proton-proton collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector.Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2.It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%.Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.