Upu, also called Apu (and Ubi or Upi by some authors), was the region surrounding Damascus of the 1350 BC Amarna letters. Damascus was named Dimašqu/Dimasqu/ etc.

Workspace optimization of 3-UPU parallel platforms with joint constraints
Kinematic sensitivity analysis of the 3-UPU parallel mechanism
Cleavage and isomerization of UpU promoted by dinuclear metal ion complexes
Kinematics and Optimization of a Spatial 3-UPU Parallel Manipulator
Prediction of the pose errors produced by joints clearance for a 3-UPU parallel robot
Unprecedentedly fast hydrolysis of the RNA dinucleoside monophosphates ApA and UpU by rare earth metal ions
Selective Hydrolysis of Phosphate Esters, Nitrophenyl Phosphates and UpU, by Dimeric Zinc Complexes Depends on the Spacer Length
On the mechanism of catalysis by ribonuclease: cleavage and isomerization of the dinucleotide UpU catalyzed by imidazole buffers
Quantitative evidence for the mechanism of RNA cleavage by enzyme mimics. Cleavage and isomerization of UpU by morpholine buffers
Trinuclear copper(II) complex showing high selectivity for the hydrolysis of 2'-5' over 3'-5' for UpU and 3'-5' over 2'-5' for ApA r...