HOUSTON — Rice Management Co., the entity that acts as steward of Rice University’s endowment, has signed new tenants to leases totaling roughly 35,000 square feet at The Ion District, a 12-block office, life sciences and innovation hub in Houston. Among the new tenants are carbon capture company Carbon Clean, Norwegian software developer Cognite and medical equipment manufacturer Motif Neurotech. These tenants join Houston-based private equity firm Ara Partners and coworking concept Common Desk. Savills represented ownership in all lease negotiations. Construction of new lab space is also now underway at The Ion District.