Cascading Failures in Power Grids: A Load Capacity Model with Node Centrality

Power grids,due to their lack of network redundancy and structural interdependence,are particularly vulnerable to cascading failures,a phenomenon where a few failed nodes—having their loads exceeding their capacities—can trigger a widespread collapse of all nodes.Here,we extend the cascading failure(Motter-Lai)model to a more realistic perspective,where each node’s load capacity is determined to be nonlinearly correlated with the node’s centrality.Our analysis encompasses a range of synthetic networks featuring small-world or scale-free properties,as well as real-world network configurations like the IEEE bus systems and the US power grid.We find that fine-tuning this nonlinear relationship can significantly enhance a network’s robustness against cascading failures when the network nodes are under attack.Additionally,the selection of initial nodes and the attack strategies also impact overall network robustness.Our findings offer valuable insights for improving the safety and resilience of power grids,bringing us closer to understanding cascading failures in a more realistic context.

Network Invulnerability Enhancement Algorithm Based on WSN Closeness Centrality

Wireless Sensor Network(WSN)is an important part of the Internet of Things(IoT),which are used for information exchange and communication between smart objects.In practical applications,WSN lifecycle can be influenced by the unbalanced distribution of node centrality and excessive energy consumption,etc.In order to overcome these problems,a heterogeneous wireless sensor network model with small world characteristics is constructed to balance the centrality and enhance the invulnerability of the network.Also,a new WSN centrality measurement method and a new invulnerability measurement model are proposed based on the WSN data transmission characteristics.Simulation results show that the life cycle and data transmission volume of the network can be improved with a lower network construction cost,and the invulnerability of the network is effectively enhanced.

Nonintubated thoracoscopic lobectomy plus lymph node dissection following segmentectomy for central type pulmonary masses

Lung cancer is the most common cancer worldwide. In the United States, it causes more cancer-related deaths than the next four causes （breast cancer, prostate cancer, colon cancer, and pancreatic cancer） of cancer-related mortality combined （1）. About 30% of people have already progressed to stage III lung cancer and 40% to stage IV at the time they are diagnosed （2）. Although chest X-ray and sputum cytology, when applied in health check-ups, can identify some relatively small tumors, they are not able to lower the overall mortality （3）. More recently,

Residual tumor and central lymph node metastasis after thermal ablation of papillary thyroid carcinoma: A case report and review of literature

BACKGROUND Debate exists regarding the use of thermal ablation(TA)to treat papillary thyroid carcinoma(PTC).Some studies have recommended TA as a new,ef
cient and safe technology for PTC.In this article,we report one case of a residual tumor and central lymph node metastasis(CLNM)after TA for PTC.CASE SUMMARY A 63-year-old female underwent bilateral ultrasound(US)-guided radiofrequency ablation for PTC.Three months later,she was diagnosed as thyroid cancer with suspected CLNM by US and contrast-enhanced computed tomography.The subsequent fine-needle aspiration(FNA)biopsies were negative.Due to her strong personal preference,she underwent total thyroidectomy and central lymph node dissection.Local tissue adhesion and a difficult dissection were noted during the operation.The pathology of the frozen sections during the operation was still negative.The final pathology results of paraffin-embedded sections revealed residual tumor cells at the edge of the PTC and CLNM.CONCLUSION TA may lead to a residual tumor in patients with PTC.Follow-up using US and FNA biopsy may not be adequate to evaluate the residual tumor.TA should be carefully considered in PTC treatment.

The Number of Lymph Nodes and Relationship with Presence of Thyroiditis and Thymic Tissue in the Central Neck Dissection Materials for Thyroid Papillary Carcinoma: Pathologic Analysis

Background: Central lymph node dissection (CLND) for papillary thyroid carcinoma (PTC) allows correct pathologic staging of lymph nodes and planning of postoperative management. The purpose of this study was to determine the number of the lymph nodes in the CLND and the relationship to presence of chronic lymphocytic thyroiditis (CLT) and thymic tissue (TT). Methods: Total thyroidectomy and CLND materials from 153 patients with PTC were included in this study. Two histopathologic features (presence of CLT and TT) were evaluated for their value in adequacy of CLND. Results: Histopathologic examination revealed CLT and TT in CLND materials in 70 (46%) and 63 (41%) patients, respectively. Total number of lymph nodes in CLND materials was significantly higher in CLT (+) and TT (+) groups (p Conclusions: Our study demonstrates that presence of CLT in thyroid gland has been associated with higher number of central lymph nodes mainly due to increased number of benign hyperplastic lymph nodes. It may be possible to conclude that upper limit of lymph nodes for satisfactory CLND would be higher to correctly evaluate central lymph node status in existing staging systems if specimens have CLT. Results of this study also show that the presence of TT in surgical materials may represent the adequacy of CLND.

Reassembly of the axon initial segment and nodes of Ranvier in regenerated axons of the central nervous system

Myelinated axons of the peripheral and central nervous system（PNS＆CNS）are divided into molecularly distinct excitable domains,including the axon initial segment（AIS）and nodes of Ranvier.The AIS is composed of a dense network of cytoskeletal proteins,cell adhesion molecules,and voltage gated ion channels and is located at the proximal most region of the axon（Koleand Stuart, 2012）.

Finding Key Node Sets in Complex Networks Based on Improved Discrete Fireworks Algorithm

Finding out the key node sets that affect network robustness has great practical significance for network protection and network disintegration.In this paper,the problem of finding key node sets in complex networks is defined firstly.Because it is an NP-hard combinatorial optimization problem,discrete fireworks algorithm is introduced to search the optimal solution,which is a swarm intelligence algorithm and is improved by the prior information of networks.To verify the effect of improved discrete fireworks algorithm(IDFA),experiments are carried out on various model networks and real power grid.Results show that the proposed IDFA is obviously superior to the benchmark algorithms,and networks suffer more damage when the key node sets obtained by IDFA are removed from the networks.The key node sets found by IDFA contain a large number of non-central nodes,which provides the authors a new perspective that the seemingly insignificant nodes may also have an important impact on the robustness of the network.

Brittleness Analysis and Important Nodes Discovery in Large Time-Evolving Complex Networks

The brittleness analysis and important nodes detection have been a hot spot in the complex networks.How to get the overall feature of the whole network and how to find out some important nodes are requisites to solve these problems. In this paper, we adopt the trace of the adjacency matrix and the centrality of the complex networks to give a quantitative and qualitative analysis of networks being studied. Results show that the k-shell plays a more important role than the degree centrality and the betweenness in finding important nodes, and it can also be used to give direction on the immunization and maintenance of complex networks.

Comparative Study between Robotic Total Thyroidectomy with Central Lymph Node Dissection via Bilateral Axillo-breast Approach and Conventional Open Procedure for Papillary Thyroid Microcarcinoma

Background： A large proportion of the patients with papillary thyroid microcarcinoma are young women. Therefore, minimally invasive endoscopic thyroidectomy with central neck dissection （CND） emerged and showed well-accepted results with improved cosmetic outcome, accelerated healing, and comforting the patients. This study aimed to evaluate the safety and effectiveness of robotic total thyroidectomy with CND via bilateral axillo-breast approach （BABA）, compared with conventional open procedure in papillary thyroid microcarcinoma. Methods： One-hundred patients with papillary thyroid microcarcinoma from March 2014 to January 2015 in Jinan Military General Hospital of People＇s Liberation Army （PLA） were randomly assigned to robotic group or conventional open approach group （17 = 50 in each group）. The total operative time, estimated intraoperative blood loss, numbers of lymph node removed, visual analog scale （VAS）, postoperative hospital stay time, complications, and numerical scoring system （NSS, used to assess cosmetic effect） were analyzed. Results： The robotic total thyroidectomy with CND via BABA was successfully performed in robotic group. There were no conversion from the robotic surgeries to open or endoscopic surgery. The subclinical central lymph node metastasis rate was 35%. The mean operative time of the robotic group was longer than that of the conventional open approach group （118.8± 16.5 min vs. 90.7± 10.3 min, P 〈 0.05）. The study showed significant differences between the two groups in terms of the VASs （2.1 ± 1.0 vs. 3.8 ±~ 1.2, P 〈 0.05） and NSS （8.9 ± 0.8 vs. 4.8 ± 1.7, P 〈 0.05）. The differences between the two groups in the estimated intraoperative blood loss, postoperative hospital stay time, numbers of lymph node removed, postoperative thyroglobulin levels, and complications were not statistically significant （all P 〉 0.05）. Neither iatrogenic implantation nor metastasis occurred in punctured porous channel or chest wall in both groups. Postoperative cosmetic results were very satisfactory in the robotic group. Conclusions： Robotic total thyroidectomy with CND via BABA is safe and effective for Chinese patients with papillary thyroid microcarcinoma who worry about the neck scars.