ETPNav: Evolving Topological Planning for Vision-Language Navigation in Continuous Environments.

Vision-language navigation is a task that requires an agent to follow instructions to navigate in environments. It becomes increasingly crucial in the field of embodied AI, with potential applications in autonomous navigation, search and rescue, and human-robot interaction. In this paper, we propose to address a more practical yet challenging counterpart setting - vision-language navigation in continuous environments (VLN-CE). To develop a robust VLN-CE agent, we propose a new navigation framework, ETPNav, which focuses on two critical skills: 1) the capability to abstract environments and generate long-range navigation plans, and 2) the ability of obstacle-avoiding control in continuous environments. ETPNav performs online topological mapping of environments by self-organizing predicted waypoints along a traversed path, without prior environmental experience. It privileges the agent to break down the navigation procedure into high-level planning and low-level control. Concurrently, ETPNav utilizes a transformer-based cross-modal planner to generate navigation plans based on topological maps and instructions. The plan is then performed through an obstacle-avoiding controller that leverages a trial-and-error heuristic to prevent navigation from getting stuck in obstacles. Experimental results demonstrate the effectiveness of the proposed method. ETPNav yields more than 10% and 20% improvements over prior state-of-the-art on R2R-CE and RxR-CE datasets, respectively. Our code is available at https://github.com/MarSaKi/ETPNav.

[Risk factors of postoperative complications of pancreatoduodenectomy].

BACKGROUND & OBJECTIVE: Pancreatoduodenectomy is the main treatment for pancreatic carcinoma and periampullary carcinoma. This study was to explore risk factors of postoperative complications of pancreatoduodenectomy for pancreatic carcinoma and periampullary carcinoma. METHODS: Clinical data of 94 patients with pancreatic carcinoma or periampullary carcinoma, underwent pancreatoduodenectomy at the second affiliated hospital of Guangzhou Medical Collage and Gansu Provincial Tumor Hospital from Jan. 1993 to Nov. 2006, were analyzed. Thirteen clinicopathologic factors that could possibly influence postoperative mortality and morbidity were selected for univariate analysis and multivariate analysis using Cox proportional hazards model. RESULTS: Univariate analysis showed that major risk factors of postoperative mortality and morbidity of the patients were total serum bilirubin level, serum album level, duration of jaundice, decompression of jaundice, operating time, intra-operative bleeding, and depth of tumor invasion (P<0.05). Multivariate analysis showed that intra-operative bleeding, operating time, total serum bilirubin level, and duration of jaundice were independent risk factors (P<0.01). CONCLUSION: Postoperative mortality and morbidity of pancreatoduodenectomy for periampullary carcinoma are closely related to intra-operative bleeding, operating time, serum bilirubin level and duration of jaundice.

[CK20 mRNA expression in peripheral blood of patients with gastrointestinal carcinoma and its clinical significance].

BACKGROUND & OBJECTIVE: Detecting expression levels of cytokeratin 19 (CK19), CK20, MUC1, and carcinoembryonic antigen (CEA) in peripheral blood,lymph node,and bone marrow is a major method for diagnosing micro-metastasis in patients with gastrointestinal carcinoma of early stages. This study was to examine the expression, before and after operation, of CK20 mRNA in peripheral blood of patients with gastrointestinal carcinoma, to further explore hematogenous-spread micro-metastasis status of these patients, and significance of CK20 mRNA detection in treatment during perioperation period. METHODS: Peripheral blood samples were collected before, and 2 weeks after operation from 62 patients with gastrointestinal carcinoma,and 22 controls (12 patients with benign gastrointestinal disease, and 10 healthy volunteers). CK20 mRNA expression in the blood samples was specifically detected by nested reverse transcriptase-polymerase chain reaction (RT-PCR). Pathologic examination of all cases was done by conventional methods. RESULTS: Of 62 patients with gastrointestinal carcinoma, 34 (54.3%) have positive CK20 mRNA expression before operation,and so did 31 (50.0%) postoperatively, but no CK20 mRNA expressed in 22 controls. In patients of stageI-IV, CK20 mRNA positive rates were 37.5% (3/8), 36.3% (8/22), 66.7% (18/27), and 100% (5/5), respectively, difference between stage I+II (36.9%) and stage III+IV (83.3%) was significant (P< 0.05). Among 35 patients with local lymph node metastasis, 27 (77.1%) were positive for CK20 mRNA; among 27 patients without lymph node metastasis, 7 (25.9%) have positive CK20 mRNA expression (P< 0.01). CK20 mRNA expression was not correlated with tumor cell differentiation,and cancer embolus existance. There was no significant difference in CK20 mRNA expression before and after operation (P >0.05). CONCLUSIONS: CK20 mRNA may be a sensitive marker for detecting micro-metastasis,and recurrence of patients with gastrointestinal carcinoma. It may be helpful for the correct clinical staging,and reasonable treatment for patients.

[Effects of short-term treatment of somatostatin on angiogenesis of gastric carcinoma].

BACKGROUND & OBJECTIVE: It is a hot spot in tumor therapies to inhibit the angiogenesis of carcinoma. Our current study was designed to investigate the inhibitory effect of somatostatin analogue on the angiogenesis of gastric carcinoma by hypodermic injection. METHODS: Twenty-five patients who have positive expression of vascular endothelial growth factor(VEGF) and somatostatin receptor 2(SSTR2)were selected by gastroscopic biopsy and immunohistochemical staining before surgical operation. After 7 days of Sandostatin administration (10 microg/kg, hypodermic injection, twice a day), the tumor extirpations were made. During the Sandostatin treatment, the serum levels of VEGF and the basic fibroblast growth factor(bFGF)were measured by enzyme-linked immunosorbant assay (ELISA) (d1,d3,d7, separately). Before and after operation,the expression levels of VEGF and bFGF were examined by Western blot analysis and the density of micro-vessels was determined by immunohistochemical staining. RESULTS: After a week of Sandostatin therapy,the concentration of VEGF and bFGF in serum was drastically diminished (VEGF:1.02+/-0.41 microg /L vs 1.88+/-0.87 microg/L, P< 0.05;bFGF:0.88+/-0.32 ng/L vs 2.12+/-1.06 ng/L,P< 0.05). The expression levels of VEGF(absorbance:1.306 vs 488,P< 0.01) and bFGF(absorbance:1.287 vs 512,P< 0.01) were obviously decreased after the remedy. The density of micro-vessels turn to the less, but there was no statistical difference before and after operation(P >0.05). CONCLUSION: By the short-term therapy of sandostatin, the expression of VEGF and bFGF can be inhibited. There is a tendency that the serum levels of VEGF and bFGF decrease with the increase of therapy time.