Product-service system (PSS) complexity is rapidly increasing in order to meet complex user requirements. Increased complexity leads to PSSs failing to meet sustainability requirements in their initial design. To enhance PSS sustainability and support social benefits, this paper proposes a sustainable PSS development framework based on design-centric complexity (DCC) theory. In the early design stage of a PSS, DCC theory is used to analyze the complexity of the system. Determination of the types of complexity in the system and the corresponding problems is then performed. By combining the sub-field model of TRIZ, the problems can be converted and solved, and the functional periodicity may be established to reduce system complexity. By using this development framework, the conflicts and potential problems of design attributes can be reduced and the possibility of achieving PSSs functional requirements (FRs) can be enhanced. This will maintain the long-term operation stability for the system and enhance the sustainability of the PSS. Finally, the feasibility of the development framework is verified here through the case analysis of a bicycle sharing service and management system.

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Rationale: Reversible splenial lesion syndrome (RESLES) is a recently identified clinico-radiological syndrome, the etiology is miscellaneous. Atrial septal defect (ASD) as an underlying etiology for RESLES has not been reported. We first report a rare case of RESLES associated with ASD. The clinical, radiological, and ultrasonic profiles were presented and the pathophysiological mechanism was analyzed. Patient concerns: A 23-year-old man presented with headache, drowsiness, occasional paraphasia, and paroxysmal dry cough. Brain magnetic resonance imaging (MRI) on admission showed an ovoid isolated lesion in the splenium of corpus callosum, which exhibited hyperintensity on diffusion-weighted imaging and hypointensity on apparent diffusion coefficient, and completely disappeared on the follow-up MRI 14 days later. ASD was found by transthoracic echocardiography, Right-to-left shunts were detected on color Doppler of transesophageal echocardiography, and microemboli were captured by transcranial Doppler ultrasound. Diagnoses: According to his clinical history and imaging results, we confirmed the diagnosis of RESLES associated with ASD. Interventions: The patient was treated by oral aspirin and lopidogrel sulfate to inhibit platelet aggregation. In addition, oral nimodipine to suppress vasoconstriction. Outcomes: After 14 days treatment, all the symptoms presenting on admission resolved completely. Subsequently, a repair surgery of ASD under thoracoscopy was successfully performed. Lessons: To our knowledge, this is the first reported case of ASD may be an underlying etiology for RESLES and need require an etiotropic treatment.