A Fast Online Elastic-Spine-Based Stiffness Adjusting Mechanism for Fishlike Swimming.

Fish tunes fishtail stiffness by coordinating its tendons, muscles, and other tissues to improve swimming performance. For robotic fish, achieving a fast and online fishlike stiffness adjustment over a large-scale range is of great significance for performance improvement. This article proposes an elastic-spine-based variable stiffness robotic fish, which adopts spring steel to emulate the fish spine, and its stiffness is adjusted by tuning the effective length of the elastic spine. The stiffness can be switched in the maximum adjustable range within 0.26 s. To optimize the motion performance of robotic fish by adjusting fishtail stiffness, a Kane-based dynamic model is proposed, based on which the stiffness adjustment strategy for multistage swimming is constructed. Simulations and experiments are conducted, including performance measurements and analyses in terms of swimming speed, thrust, and so on, and online stiffness adjustment-based multistage swimming, which verifies the feasibility of the proposed variable stiffness robotic fish. The maximum speed and lowest cost of transport for robotic fish are 0.43 m/s (equivalent to 0.81 BL/s) and 7.14 J/(kg·m), respectively.

Effect of pretreatment with a small dose of esketamine on sufentanil-induced cough during anesthesia induction: a randomized controlled trial.

BACKGROUND: Sufentanil-induced cough is common during the induction of anesthesia. The objective of this study was to determine whether pretreatment with a small dose of esketamine is effective in treating sufentanil-induced cough. METHODS: 220 patients were screened, and 200 patients who had scheduled elective surgery and were between 18 and 70 years old were randomly divided into two groups. Before sufentanil was administered, esketamine group (group K) was injected with 0.15 mg/kg esketamine at 5 s, and control group (group C) was administered with the same volume. Within 1 min after sufentanil(0.4ug/kg) injection during induction, cough incidence and severity were evaluated. After sufentanil was injected, we recorded its hemodynamic changes and side effects. RESULTS: In the esketamine group (group K) and control group (group C), there was an incidence of cough of 5 and 34%, respectively. The esketamine group (group K) had a significantly lower incidence and severity of cough compared to the control group (group C) immediately after sufentanil injection (P < 0.05). MAP and HR did not differ significantly between the two groups during three different times of general anesthesia induction (P > 0.05). CONCLUSION: In our study, we found that sufentanil-induced cough was significantly reduced by pretreatment with 0.15 mg/kg esketamine, but with no significant changes in the hemodynamic status. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2200063821, registered date: 17/09/2022), http://www.chictr.org.cn.

Esketamine inhibits the c-Jun N-terminal kinase pathway in the spinal dorsal horn to relieve bone cancer pain in rats.

Cancer-induced bone pain (CIBP) is one of the most common and feared symptoms in patients with advanced tumors. The X-C motif chemokine ligand 12 (CXCL12) and the CXCR4 receptor have been associated with glial cell activation in bone cancer pain. Moreover, mitogen-activated protein kinases (MAPKs), as downstream CXCL12/CXCR4 signals, and c-Jun, as activator protein AP-1 components, contribute to the development of various types of pain. However, the specific CIBP mechanisms remain unknown. Esketamine is a non-selective N-methyl-d-aspartic acid receptor (NMDA) inhibitor commonly used as an analgesic in the clinic, but its analgesic mechanism in bone cancer pain remains unclear. We used a tumor cell implantation (TCI) model and explored that CXCL12/CXCR4, p-MAPKs, and p-c-Jun were stably up-regulated in the spinal cord. Immunofluorescence images showed activated microglia in the spinal cord on day 14 after TCI and co-expression of CXCL12/CXCR4, p-MAPKs (p-JNK, p-ERK, p-p38 MAPK), and p-c-Jun in microglia. Intrathecal injection of the CXCR4 inhibitor AMD3100 reduced JNK and c-Jun phosphorylations, and intrathecal injection of the JNK inhibitor SP600125 and esketamine also alleviated TCI-induced pain and reduced the expression of p-JNK and p-c-Jun in microglia. Overall, our data suggest that the CXCL12/CXCR4-JNK-c-Jun signaling pathway of microglia in the spinal cord mediates neuronal sensitization and pain hypersensitivity in cancer-induced bone pain and that esketamine exerts its analgesic effect by inhibiting the JNK-c-Jun pathway.

Tail-stiffness optimization for a flexible robotic fish.

Undulation regulation in a robotic fish propelled by a passive flexible tail is more similar to that of a natural fish than with a rigid tail, owing to the smooth curvature of the flexible tail. Moreover, it has been observed that fish change the stiffness of their bodies to adapt to various swimming states. Inspired by this, a stiffness optimization scheme is explored for a novel elastic tail, which can improve the performance of the robotic fish. Spring steels are used as passive flexible joints of the fishtail; these can be easily expanded into multi-joint structures and the joint stiffness can be altered by changing the joint size. In this study, the Lagrangian dynamic method is employed to establish a dynamic model of the robotic fish in which passive flexible joints are simplified by a pseudo-rigid-body model. In addition, the hydrodynamics of the head and tail are analyzed using the simplified Morison equation and quasi-steady wing theory, respectively. Furthermore, to determine unknown hydrodynamic parameters in the dynamic model, a parameter identification method is applied. The results show that the identified simulation speeds fit the experimental speeds well within a wide range of stiffness values. Finally, to improve performance, the influence of joint stiffness and frequency on swimming speed is investigated based on the identified dynamic model. At each frequency, the optimal joint stiffness distribution is one that reduces the stiffness from the front to the rear. At the maximum driving frequency of 2.5 Hz, the optimal swimming speed is 0.3 body lengths per second, higher than that when rigid joints are used.

Use of the peritoneum or the round ligament of the liver in radical surgery for pancreatic cancer.

BACKGROUND: At present, the materials commonly used for venous reconstruction in radical surgery for pancreatic cancer combined with vascular reconstruction include artificial blood vessels, autologous veins, and allogeneic blood vessels, but these materials all have their own disadvantages. In contrast, the use of the peritoneum and the round ligament of the liver for radical surgery for pancreatic cancer combined with vascular reconstruction provides new options. METHODS: A retrospective descriptive study was performed. Clinical data were collected from 11 patients (5 males and 6 females with a median age of 62 years and an age range of 48-72 years) who underwent pancreatic cancer surgery combined with resection and reconstruction of the portal vein (PV) and superior mesenteric vein (SMV) using the peritoneum (including the round ligament of the liver) from November 2018 to November 2020 in the Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, and the Department of General Surgery, Affiliated Hospital of Shaoxing University. Intraoperative conditions and postoperative conditions were observed. Data were analyzed using SPSS 19.0 Normally distributed measurement data are expressed as the mean ± SD, whereas nonnormally distributed measurement data are expressed as the median (range). Count data are expressed as absolute numbers. RESULTS: (I) Intraoperative condition: all 11 patients completed the operation successfully, including total pancreatectomy (TP) in 4 patients and pancreatoduodenectomy (PD) in 7 patients. In the 11 patients, the duration of surgery was 503±183 min, and the volume of intraoperative bleeding was 332±268 mL. (II) Postoperative condition: of the 11 patients, 5 presented with complications, including pancreatic leak in 3 patients, bleeding in 1 patient, and thrombosis in 1 patient. Postoperative pathological examination showed that 10 of the 11 patients had adenocarcinoma, and 1 had a neuroendocrine tumor. CONCLUSIONS: The peritoneum and the round ligament of the liver are feasible materials and provide clinical options for reconstruction of the PV and SMV.

Erratum: GATA3 is downregulated in HCC and accelerates HCC aggressiveness by transcriptionally inhibiting slug expression.

[This corrects the article DOI: 10.3892/ol.2021.12492.].

GATA3 is downregulated in HCC and accelerates HCC aggressiveness by transcriptionally inhibiting slug expression.

Previous studies have reported that GATA3 is downregulated in multiple types of tumours, including gastric cancer and osteosarcoma. The aim of this study was to explore whether GATA3 serves as a tumour suppressor to inhibit hepatocellular carcinoma (HCC) development. Tumour tissue specimens and adjacent normal tissue specimens were obtained from 162 patients diagnosed with HCC in the Affiliated Hospital of Shaoxing University from July 2000 to May 2018. The result of the present study demonstrated that GATA3 was downregulated in HCC tumour tissues compared with that of adjacent normal tissues. The expression of GATA3 was also negatively associated with tumour size, TNM stage and lymph node metastasis. Additionally, analysis of the follow-up data revealed that low GATA3 expression was closely correlated with poor survival. Gain and loss of function analyses revealed that overexpression of GATA3 decreased the ability of proliferation, migration and invasion in HCC cell lines, whereas inhibition of GATA3 promoted the ability of proliferation, migration and invasion. In addition, GATA3 suppressed EMT through the regulation of slug expression. Additionally, slug overexpression attenuated the inhibitory effects of GATA3 overexpression on cancer cell proliferation, migration and invasion. Thus, GATA3 is downregulated in HCC, and suppresses cell proliferation, migration and invasion. Moreover, GATA3 transcriptionally inhibits slug expression, thereby suppressing EMT in HCC.