Economic statistical design of x ¥ control charts for systems with gamma ( 5 ,2) in-control times

In this paper, gamma ( 5 ,2) distribution is considered as a failure model for the economic statistical design of x ¥ control charts. The study shows that the statistical performance of control charts can be improved significantly, with only a slight increase in the cost, by adding constraints to the optimization problem. The use of an economic statistical design instead of an economic design results in control charts that may be less expensive to implement, that have lower false alarm rates, and that have a higher probability of detecting process shifts. Numerical examples are presented to support this proposition. The results of economic statistical design are compared with those of a pure economic design. The effects of adding constraints for statistical performance measures, such as Type I error rate and the power of the chart, are extensively investigated.

Short ligands affect modes of QD uptake and elimination in human cells

In order to better understand nanoparticle uptake and elimination mechanisms, we designed a controlled set of small, highly fluorescent quantum dots (QDs) with nearly identical hydrodynamic size (8–10 nm) but with varied short ligand surface functionalization. The properties of functionalized QDs and their modes of uptake and elimination were investigated systematically by asymmetrical flow field–flow fractionation (AF4), confocal fluorescence microscopy, flow cytometry (FACS), and flame atomic absorption (FAA). Using specific inhibitors of cellular uptake and elimination machinery in human embryonic kidney cells (Hek 293) and human hepatocellular carcinoma cells (Hep G2), we showed that QDs of the same size but with different surface properties were predominantly taken up through lipid raft-mediated endocytosis, however, to significantly different extents. The latter observation infers the contribution of additional modes of QD internalization, which include X-AG cysteine transporter for cysteine-functionalized QDs (QD-CYS). [...

Axillary tumour burden in women with one abnormal node on ultrasound compared to women with multiple abnormal nodes.

AIM: To determine if the number of abnormal nodes seen on preoperative axillary ultrasound (AUS) is a predictor of the number of positive nodes at histology for women with needle-biopsy-proven positive nodes. MATERIALS AND METHODS: This prospective multicentre cohort study included consecutive patients with early breast cancer who had needle-biopsy-proven positive nodes on AUS and underwent axillary lymph node dissection (ALND) between October 2015 and July 2016. The number of abnormal nodes at preoperative AUS was recorded by breast radiologists or radiographers. RESULTS: One hundred and twenty-three patients were included in the study. The median age of the women was 62 (range 30-93) years. Fifty-four of the 123 (44%) women had one abnormal node, whereas 69 (56%) had multiple abnormal nodes on AUS. Forty of the 123 (33%) women had two or fewer nodes with metastases at histology after ALND. Tumours ≤20 mm (p<0.001) and one abnormal node on AUS (p<0.001) were associated with two or fewer nodes with metastases at ALND. Both remained significant in logistic regression analysis. The likelihood of at least three metastases based on the combination of these two factors had 95% sensitivity (79 of 83), 35% specificity (14 of 40), a negative predictive value of 78% (14 of 18), and a positive predictive value of 75% (79 of 105). CONCLUSION: Among women with needle-biopsy-proven positive nodes, around three in four women (78%) with an invasive tumour ≤2 cm and one abnormal node on AUS have two or fewer positive nodes at ALND. These women are overtreated by upfront ALND and can be offered sentinel node biopsy (SNB)