BackgroundThe most effective and radical treatment for pancreatic neuroendocrine tumors (PNETs) is surgical resection. Minimally invasive surgery has been increasingly used in pancreatectomy. Initial results in robotic distal pancreatectomy (RDP) have been encouraging. Nonetheless, data comparing outcomes of RDP with those of laparoscopic distal pancreatectomy (LDP) in treating PNETs are rare. The aim of this study was to compare the safety and efficacy of RDP and LDP for PNETs.MethodsFrom September 2010 to January 2017, operative parameters and perioperative outcomes in an initial experience with 43 consecutive patients undergoing RDP were collected and compared with those in 31 patients undergoing LDP.ResultsPatients undergoing RDP and LDP demonstrated equivalent age, sex, ASA score, tumor location and tumor size. Operating time, length of resected pancreas, postoperative length of hospital stay and rates of conversion to open, pancreatic fistula, transfusion and reoperation were not statistically different. Patients in the RDP group were associated with significantly higher overall (79.1 vs. 48.4 %, P = 0.006) and Kimura spleen preservation rates (72.1 vs. 16.1%, P < 0.001) and had reduced risk of excessive blood loss (50 vs. 200mL, P < 0.001). Oncological outcomes in this series were superior for the RDP group with more lymph node harvest for G2 and G3 PNETs (3.5 vs. 2, P = 0.034).ConclusionsBoth RDP and LDP are efficacious and safe methods in treating PNETs located in the body or tail of pancreas. Robotic approach offers advantages with less intraoperative blood loss, higher spleen preservation rate and more lymph node harvest. It may be sensible to choose RDP for patients who fit indications for scheduled spleen preservation.

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In this paper, we study the problem of reliable collective communication (broadcast or gossip) with the objective of maximizing the reliability of the collective communication. The need for collective communication arises in many problems of parallel and distributed computing, including Grid or cloud computing and database management. We describe the network model, formulate the reliable collective communication problem, prove that the maximum reliable collective communication problem is NP-hard, and provide an integer linear program (ILP) formulation for the problem. We then provide a greedy approximation algorithm to construct collective communication (through a spanning tree) that achieves an approximation ratio of , where is the average number of shared link risk groups (SRLGs) along links, and and are the total number of vertices and edges of the network, respectively. Simulations demonstrate that our approximation algorithm achieves good performance in both small and large networks and that, in almost 95% of total cases, our algorithm outperforms the modified minimum spanning tree algorithms. Index Terms-Approximation algorithm, optical network, reliable collective communication (RCC), shared link risk group (SRLG).

Magnetic resonance imaging (MRI) is a non-invasive imaging technology to diagnose health conditions, showing the weakness of low sensitivity. Herein, we synthesize a contrast agent, SPIO@SiO2@MnO2, which shows decreased T1 and T2 contrast intensity in normal physiological conditions. In the acid environment of tumor or inflamed tissue, the manganese dioxide (MnO2) layer decomposes into magnetically active Mn2+ (T1-weighted), and the T1 and T2 signals are sequentially recovered. In addition, both constrast quenching-activation degrees of T1 and T2 images can be accurately regulated by the silicon dioxide (SiO2) intermediate layer between superparamagnetic iron oxide (SPIO) and MnO2. Through the “dual-contrast enhanced subtraction” imaging processing technique, the contrast sensitivity of this MRI contrast agent is enhanced to a 12.3-time difference between diseased and normal tissue. Consequently, SPIO@SiO2@MnO2 is successfully applied to trace the tiny liver metastases of approximately 0.5 mm and monitor tissue inflammation.