Observation of non-Hermitian skin effect in thermal diffusion.

The paradigm shift of Hermitian systems into the non-Hermitian regime profoundly modifies inherent property of the topological systems, leading to various unprecedented effects such as the non-Hermitian skin effect (NHSE). In the past decade, the NHSE has been demonstrated in quantum, optical and acoustic systems. Beside those wave systems, the NHSE in diffusive systems has not yet been observed, despite recent abundant advances in the study of topological thermal diffusion. In this work, we design a thermal diffusion lattice based on a modified Su-Schrieffer-Heeger model and demonstrate the diffusive NHSE. In the proposed model, the asymmetric temperature field coupling inside each unit cell can be judiciously realized by appropriate configurations of structural parameters. We find that the temperature fields trend to concentrate toward the target boundary which is robust against initial excitation conditions. We thus experimentally demonstrated the NHSE in thermal diffusion and verified its robustness against various defects. Our work provides a platform for exploration of non-Hermitian physics in the diffusive systems, which has important applications in efficient heat collection, highly sensitive thermal sensing and others.

High-Performance Curved Piezoelectric Single-Crystal Composites via 3D-Printing-Assisted Dice and Insert Technology for Underwater Acoustic Transducer Applications.

Piezoelectric single-crystal composites (PSCCs) have been studied and applied because of their improved resolution and power source level performance in underwater acoustic transducer applications relative to traditional piezoelectric ceramic composites (PCCs). Currently, the methods to fabricate curved PSCCs are mostly derived from PCCs, including molding with flexible backing, molding with heating, and molding with the casting rubber method. Unfortunately, the methods mentioned above are not suitable for preparing curved PSCCs for underwater acoustic transducer applications because of their brittleness, the large anisotropy of piezoelectric single crystals, and the high thickness (>2 mm) of PSCCs for achieving the low operating frequency (<700 kHz). In the present work, we proposed a preparation method, 3D-printing-assisted dice and insert technology, and successfully prepared curved PSCCs with high performance. Although the PSCCs have a low volume fraction of single crystals in this work (∼33%), a high thickness electromechanical factor kt of 86% and a large piezoelectric coefficient d33 of 1550 pC/N were achieved in the curved 1-3 PSCCs, which are superior to other reported PSCCs and PCCs with nearly the same volume fraction of single crystals and piezoelectric ceramics. This work presents a paradigm for fabricating curved PSCCs for underwater acoustic transducers, and this method shows the potential for large-area, special-shaped PSCCs, which are key materials for next-generation underwater acoustic transducers.

Efficacy and safety of carotid endarterectomy in treatment of different neurological deficits / 局解手术学杂志

Objective To study the efficacy and safety of carotid endarterectomy ( CEA) in the treatment of carotid artery stenosis with different neurological deficits .Methods The clinical data of 59 patients with carotid stenosis treated by carotid endarterectomy in the department of neurosurgery of affiliated hospital of Xuzhou medical university from September 2015 to February 2017 were analyzed retrospectively ,a total of 62 operations were performed in these patients ( including 3 patients accepted bilateral operation ) .According to the preoperative 1 day nerve function which evaluated by the modified Rankin scale (mRS)score,they were divided into mRS <3 group(n=47),mRS≥3 group (n=15).They were followed up for 6 to 24 months,the neurological function of 62 patients was scored again by mRS at 6 months after sur-gery.The clinical data and the difference of surgical efficacy and safety of perioperative period between the 2 groups were analyzed and com-pared.Results The 62 times of operations were successful in patients .The neurological function of the 2 groups were significantly improved compared with the preoperative,the difference was statistically significant(P<0.05).In the mRS≥3 group,there were 1 patients with perio-perative cerebral infarction died of cerebral hernia ,1 case of consciousness disorder caused by high perfusion and 1 cases of postoperative in-tracranial hemorrhage caused by high perfusion .In the mRS<3 group,there was 1 case left contralateral hemiplegia caused by a large area of cerebral infarction .The incidence of cerebral apoplexy within 30 days after procedure in the mRS≥3 group was significantly higher than that in the mRS<3 group.There was no new stroke in 61 patients during the long-term follow-up.Conclusion Mild(mRS<3) and severe(mRS≥3) of patients has improved nervous function from CEA;perioperative risk of patients with severe neurological deficits is relatively higher , but the preventive effect for the prevention of ischemic stroke recurrence is worthwhile .

MiR-206 Attenuates Denervation-Induced Skeletal Muscle Atrophy in Rats Through Regulation of Satellite Cell Differentiation via TGF-ß1, Smad3, and HDAC4 Signaling.

BACKGROUND Denervation-induced skeletal muscle atrophy results in significant biochemical and physiological changes potentially leading to devastating outcomes including increased mortality. Effective treatments for skeletal muscle diseases are currently not available. Muscle-specific miRNAs, such as miR-206, play an important role in the regulation of muscle regeneration. The aim of the present study was to examine the beneficial effects of miR-206 treatment during the early changes in skeletal muscle atrophy, and to study the underlying signaling pathways in a rat skeletal muscle atrophy model. MATERIAL AND METHODS The rat denervation-induced skeletal muscle atrophy model was established. miRNA-206 was overexpressed with or without TGF-ß1 inhibitor in the rats. The mRNA and protein expression of HDAC4, TGF-ß1, and Smad3 was determined by real-time PCR and western blot. The gastrocnemius muscle cross-sectional area and relative muscle mass were measured. MyoD1, TGF-ß1, and Pax7 were determined by immunohistochemical staining. RESULTS After sciatic nerve surgical transection, basic muscle characteristics, such as relative muscle weight, deteriorated continuously during a 2-week period. Injection of miR-206 (30 µg/rat) attenuated morphological and physiological deterioration of muscle characteristics, prevented fibrosis effectively, and inhibited the expression of TGF-ß1 and HDAC4 as assessed 2 weeks after denervation. Moreover, miR-206 treatment increased the number of differentiating (MyoD1+/Pax7+) satellite cells, thereby protecting denervated muscles from atrophy. Interestingly, the ability of miR-206 to govern HDAC4 expression and to attenuate muscle atrophy was weakened after pharmacological blockage of the TGF-b1/Smad3 axis. CONCLUSIONS TGF-ß1/Smad3 signaling pathway is one of the crucial signaling pathways by which miR-206 counteracts skeletal muscle atrophy by affecting proliferation and differentiation of satellite cells. miR-206 may be a potential target for development of a new strategy for treatment of patients with early denervation-induced skeletal muscle atrophy.