BALLU2: A Safe and Affordable Buoyancy Assisted Biped.

This work presents the first full disclosure of BALLU, Buoyancy Assisted Lightweight Legged Unit, and describes the advantages and challenges of its concept, the hardware design of a new implementation (BALLU2), a motion analysis, and a data-driven walking controller. BALLU is a robot that never falls down due to the buoyancy provided by a set of helium balloons attached to the lightweight body, which solves many issues that hinder current robots from operating close to humans. The advantages gained also lead to the platform's distinct difficulties caused by severe nonlinearities and external forces such as buoyancy and drag. The paper describes the nonconventional characteristics of BALLU as a legged robot and then gives an analysis of its unique behavior. Based on the analysis, a data-driven approach is proposed to achieve non-teleoperated walking: a statistical process using Spearman Correlation Coefficient is proposed to form low-dimensional state vectors from the simulation data, and an artificial neural network-based controller is trained on the same data. The controller is tested both on simulation and on real-world hardware. Its performance is assessed by observing the robot's limit cycles and trajectories in the Cartesian coordinate. The controller generates periodic walking sequences in simulation as well as on the real-world robot even without additional transfer learning. It is also shown that the controller can deal with unseen conditions during the training phase. The resulting behavior not only shows the robustness of the controller but also implies that the proposed statistical process effectively extracts a state vector that is low-dimensional yet contains the essential information of the high-dimensional dynamics of BALLU's walking.

The Prognostic Value of Circumferential Resection Margin Involvement in Patients with Extraperitoneal Rectal Cancer.

The prognostic influence of circumferential resection margin (CRM) status in extraperitoneal rectal cancer probably differs from that of intraperitoneal rectal cancer because of its different anatomical and biological behaviors. However, previous reports have not provided the data focused on extraperitoneal rectal cancer. Therefore, the aim of this study was to examine the prognostic significance of the CRM status in patients with extraperitoneal rectal cancer. From January 2005 to December 2008, 248 patients were treated for extraperitoneal rectal cancer and enrolled in a prospectively collected database. Extraperitoneal rectal cancer was defined based on tumors located below the anterior peritoneal reflection, as determined intraoperatively by a surgeon. Cox model was used for multivariate analysis to examine risk factors of recurrence and mortality in the 248 patients, and multivariate logistic regression analysis was performed to identify predictors of recurrence and mortality in 135 patients with T3 rectal cancer. CRM involvement for extraperitoneal rectal cancer was present in 29 (11.7%) of the 248 patients, and was the identified predictor of local recurrence, overall recurrence, and death by multivariate Cox analysis. In the 135 patients with T3 cancer, CRM involvement was found to be associated with higher probability of local recurrence and mortality. In extraperitoneal rectal cancer, CRM involvement is an independent risk factor of recurrence and survival. Based on the results of the present study, it seems that CRM involvement in extraperitoneal rectal cancer is considered an indicator for (neo)adjuvant therapy rather than conventional TN status.

Implication of minimal extrathyroidal extension as a prognostic factor in papillary thyroid carcinoma.

PURPOSE: Extrathyroidal extension (ETE) of papillary thyroid carcinoma (PTC) is a risk factor for tumor recurrence. By TNM Classification (7th edition), differentiated thyroid carcinoma with ETE is designated T3 (minimal invasion), T4a (extended invasion), or T4b (more extensive unresectable invasion), according to the degree of tumor involvement. We subsequently focused our investigation on minimal ETE (MEE), analyzing the clinicopathologic characteristics, recurrence rate, and recurrence-free survival (RFS) in this setting. METHODS: A retrospective study was conducted, based on 332 patients undergoing thyroidectomy for PTC between January 2005 and December 2006. RESULTS: The study population was stratified into two groups: PTC with MEE (103/332; 31.0%) and PTC without MEE (229/332; 69.0%). In patients with PTC, MEE correlated with gender, tumor size, multifocality, lymph node (LN) metastasis, underlying Hashimoto's thyroiditis, and the nature of the surgery. However, no significant intergroup differences were evident with respect to age, recurrence rate, and LN metastasis. In multivariate analysis, LN metastasis (odds ratio = 2.273; 95% confidence interval, 1.280-4.037) was recognized as an independent correlate of mETE (p = 0.005). However, recurrence-free survival did not differ significantly between the groups (p = 0.153), even when further stratified by the presence or absence of LN metastasis. CONCLUSION: In patients with PTC, MEE does not impact RFS. Thus, appropriate surgical intervention and postoperative follow up are mandatory in PTC, regardless of its extent.

Adipose-derived stem cells on the healing of ischemic colitis: a therapeutic effect by angiogenesis.

BACKGROUND: There has been no specific treatment for ischemic colitis. We verified the effects of adipose-derived stem cells (ASCs) on ischemia-induced colitis in a rat model. METHODS: Forty male Sprague-Dawley rats (10 weeks old; weight, 350 ± 20 g) were divided into two groups: a control group (only fibrinogen and thrombin injected, n = 20) and an ASC group (local implantation of ASCs mixed with thrombin and fibrinogen, n = 20). An ischemic colitis model was established by modifying Nagahata's methods with double-blind randomization. ASCs (1 × 10(6) cells) were implanted intramurally into the ischemic area using a fibrin glue mixture. The severity of adhesion, degree of ileus, the number and size of the ulcers, Wallace macroscopic and microscopic scores, and microvascular density were measured. RESULTS: The degree of ileus was significantly lower, and significantly fewer and smaller ulcerations were found in the ASC group than those in the control group. Wallace macroscopic and microscopic scores were lower in the ASC group than in the control group (1.90 ± 1.22 versus 3.25 ± 1.83, p < 0.01 and 1.55 ± 1.88 versus 2.84 ± 1.89, p < 0.05, respectively). Microvascular density was higher in the ASC group than in the control (54.45 ± 19.45 versus 26.54 ± 13.14, p < 0.01, respectively). CONCLUSIONS: Local implantation of ASCs into an ischemic-injured colonic wall reduced the grade of ischemic injury and enhanced tissue healing by promoting angiogenesis.