The Natural Neighbor Radial Point Interpolation Method Extended to the Crack Growth Simulation

In the present work, the Natural Neighbor Radial Point Interpolation Method (NNRPIM) is used to simulate the crack growth phenomenon in brittle materials. In order to discretize the problem domain, the NNRPIM only requires an unstructured nodal distribution. With the spatial information of the computational nodes, the NNRPIM is capable to automatically establish the nodal connectivity and to construct the interpolation functions. Additionally, using the natural neighbor geometrical concept, the NNRPIM is able to obtain, from the unstructured nodal distribution, the integration background mesh required to numerically integrate the integro-differential equations ruling the studied physical phenomenon. In this work, a crack opening path algorithm is adapted and combined with the NNRPIM. The developed algorithm is able to predict the crack growth by relocating iteratively the crack tip. The stress field in the vicinity of the crack tip is determined in each iteration and then, using the maximum circumferential stress criterion, the direction of the crack propagation is calculated. Here, the repositioning of the crack tip requires a local re-meshing. However, due to the flexibility of the natural neighbor concept, the local re-meshing do not represent a numerical difficulty. Additionally, in order to show the efficiency of the proposed approach, several demanding crack growth benchmark examples are solved.

Detection of Sentinel Nodes for Endometrial Cancer With Robotic Assisted Fluorescence Imaging: Cervical Versus Hysteroscopic Injection

ObjectiveSentinel lymph node (SLN) mapping with indocyanine green (ICG) detected by robotic near infrared (NIR) imaging is a feasible technique. The optimal site of injection (cervical or endometrial) for endometrial cancer has yet to be determined. We prospectively evaluated SLN mapping after cervical and endometrial injections of ICG to compare the detection rates and patterns of nodal distribution.MethodsTwenty-nine subjects with endometrial cancer undergoing robotic hysterectomy with lymphadenectomy by a single surgeon received SLN mapping with robotic fluorescence imaging. Seventeen patients received cervical injections of 1 mg of ICG and 12 patients received hysteroscopic endometrial injections of 0.5-mg ICG. Detection rates between the 2 groups were compared using Fisher exact tests. Continuous variables such as operating room times and body mass index were compared usingttests.ResultsThe SLN detection rate was 82% (14/17) for cervical and 33% (4/12) for hysteroscopic injection (P= 0.027). Sentinel lymph nodes were seen bilaterally in 57% (8/14) of the cervical injection group and 50% (2/4) of the hysteroscopic group. Para-aortic SLNs were seen in 71% (10/14) of patients who mapped after cervical injection and 75% (3/4) patients who mapped after hysteroscopic injection. There was 1 false-negative SLN in the cervical injection group.ConclusionsCervical ICG injection achieves a higher SLN detection rate and a similar anatomic nodal distribution as hysteroscopic endometrial injection for SLN mapping in patients with endometrial cancer.

Nodal distribution of free polyamines in cotton ovaries

SUMMARYThe nodal distribution of free polyamines (important regulators of flower induction) in cotton (Gossypium hirsutum L.) ovaries was determined by high-performance liquid chromatography (HPLC). The objective of the study was to investigate the nodal distribution of putrescine (Put), spermidine (Spd) and spermine (Sp) of cotton lines (G. hirsutum L.), and to determine whether there are differences in ovarian polyamine content among three commercial cotton cultivars. A field study was conducted in 2005 and 2006 using the cultivars FM960BR, ST5599BR and DP444BR. Free polyamines Put, Spd and Sp were determined in ovarian tissue of first-position white flowers starting at the beginning of anthesis and collected from the 7th, 9th, 11th and 13th main-stem nodes for four consecutive weeks. There was no significant nodal position by cultivar interaction; thus, the main effects were tested. Put content decreased acropetally along the main stem of the cotton plant with the highest content observed at the 7th node and the lowest at the 13th node. Spd content decreased below and above the 9th node, with the 9th node showing the highest amount of Spd and the 13th node the lowest in both years of the study. Similarly, Sp content decreased below and above the 9th node. In general, the 7th and the 9th node had the highest titre of free polyamines. Among the cultivars tested, FM960BR showed higher polyamine content in one season; however, the observation was not consistent from year to year. The highest amounts of polyamines were observed at the 7th and the 9th node of cotton and this may be associated with the known yield distribution: almost 0·80 of the total yield of cotton is derived from these nodal positions.