Analytical paradigms have limited conventional form-finding methods of tensegrities; therefore, an innovative approach is urgently needed. This paper proposes a new form-finding method based on state-of-the-art deep learning techniques. One of the statical paradigms, a force density method, is substituted for trained deep neural networks to obtain necessary information of tensegrities. It is based on the differential evolution algorithm, where the eigenvalue decomposition process of the force density matrix and the process of the equilibrium matrix are not needed to find the feasible sets of nodal coordinates. Three well-known tensegrity examples including a 2D two-strut, a 3D-truncated tetrahedron and an icosahedron tensegrity are presented for numerical verifications. The cases of the ReLU and Leaky ReLU activation functions show better results than those of the ELU and SELU. Moreover, the results of the proposed method are in good agreement with the analytical super-stable lines. Three examples show that the proposed method exhibits more uniform final shapes of tensegrity, and much faster convergence history than those of the conventional one.
6 August 2016 in Structural and Multidisciplinary Optimization
The appropriate management of vitamin D deficiency and hyperparathyroidism is essential to prevent metabolic bone disorder (MBD) and cardiovascular diseases in chronic kidney disease (CKD). Recently, the 24,25-dihydroxyvitamin D [24,25(OH)2D] and vitamin D metabolite ratio (VMR), i.e., the ratio of 24,25(OH)2D to 25-hydroxyvitamin D [25(OH)D], have emerged as biomarkers of vitamin D level. We analyzed the usefulness of vitamin D biomarkers for the evaluation of MBD in patients with CKD. We analyzed blood and urine samples from 208 outpatients with CKD stage G2–G5. 25(OH)D showed a poor correlation with the estimated glomerular filtration rate (eGFR). Conversely, the 24,25(OH)2D level and VMR were significantly correlated with eGFR and the intact parathyroid hormone level. In conclusion, 24,25(OH)2D and VMR have the potential to be vitamin D biomarkers for the detection of MBD in CKD patients.
Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) and progression to chronic kidney disease (CKD). However, no effective therapeutic intervention has been established for ischemic AKI. Endothelial progenitor cells (EPCs) have major roles in the maintenance of vascular integrity and the repair of endothelial damage; they also serve as therapeutic agents in various kidney diseases. Thus, we examined whether EPCs have a renoprotective effect in an IRI mouse model. Mice were assigned to sham, EPC, IRI-only, and EPC-treated IRI groups. EPCs originating from human peripheral blood were cultured. The EPCs were administered 5 min before reperfusion, and all mice were killed 72 h after IRI. Blood urea nitrogen, serum creatinine, and tissue injury were significantly increased in IRI mice; EPCs significantly improved the manifestations of IRI. Apoptotic cell death and oxidative stress were significantly reduced in EPC-treated IRI mice. Administration of EPCs decreased the expression levels of NLRP3, cleaved caspase-1, p-NF-κB, and p-p38. Furthermore, the expression levels of F4/80, ICAM-1, RORγt, and IL-17RA were significantly reduced in EPC-treated IRI mice. Finally, the levels of EMT-associated factors (TGF-β, α-SMA, Snail, and Twist) were significantly reduced in EPC-treated IRI mice. This study shows that inflammasome-mediated inflammation accompanied by immune modulation and fibrosis is a potential target of EPCs as a treatment for IRI-induced AKI and the prevention of progression to CKD.
Rationale: Renal artery pseudoaneurysm is a rare vascular lesion usually caused by trauma or percutaneous urological procedures. Spontaneous rupture of pseudoaneurysms without predisposing events, especially in hemodialysis patients, has rarely been reported. Patient concerns: A 25-year-old man receiving maintenance hemodialysis visited the emergency room because of sudden severe right flank pain. He had no history of trauma or urological procedures except for a left renal biopsy to diagnose Alport syndrome 10 years prior. Diagnosis: Contrast-enhanced computed tomography revealed a right perirenal hematoma with pseudoaneurysms. Interventions: On renal angiography, multiple pseudoaneurysms were observed in the right renal artery branches and embolization was performed. Outcomes: Post-angiography showed no pseudoaneurysms. His abdominal pain improved, and he was discharged 2 weeks after embolization. Lessons: When maintenance dialysis patients complain of severe abdominal pain, spontaneous rupture of a renal pseudoaneurysm should be considered as a differential diagnosis, even if the patient has no history of trauma or previous urological procedures.