UNASSIGNED: The 2015 American Thyroid Association (ATA) Guidelines recommend the following size cut-offs based on sonographic appearances for subjecting nodules to fine-needle aspiration (FNA) biopsy: low risk: 15 mm and intermediate risk and high risk: 10 mm.
UNASSIGNED: We conducted a \'real-world\' study evaluating the diagnostic performance of the ATA cut-offs against increased thresholds, in the interest of safely limiting FNAs.
UNASSIGNED: We performed a retrospective analysis of prospectively collected data on 604 nodules which were sonographically risk-stratified as per the ATA Guidelines and subsequently subjected to ultrasound-guided FNA. Nodules were cytologically stratified into \'benign\' (Bethesda class 2) and \'non-benign\' (Bethesda classes 3-6). We obtained the negative predictive value (NPV), accuracy, FNAs that could be spared, missed \'non-benign\' cytologies and missed carcinomas on histology, according to the ATA cut-offs compared to higher cut-offs.
UNASSIGNED: In low-risk nodules, the high performance of NPV (≈91%) is unaffected by increasing the cut-off to 25 mm, and accuracy improves by 39.4%; 46.8% of FNAs could be spared at the expense of few missed B3-B6 cytologies (7.9%) and no missed carcinomas. In intermediate-risk nodules, a 15 mm cut-off increases the NPV by 11.3% and accuracy by 40.7%. The spared FNAs approach 50%, while B3-B6 cytologies are minimal, with no missed carcinomas. In high-risk nodules, low NPV (<35%) and accuracy (<46%) were obtained regardless of cut-off. Moreover, the spared FNAs achieved at higher cut-offs involved numerous missed \'non-benign\' cytologies and carcinomas.
UNASSIGNED: It would be clinically safe to increase the ATA cut-offs for FNA in low-risk nodules to 25 mm and in intermediate-risk nodules to 15 mm.

Intertidal organisms are subjected to intense hydrodynamic forces as waves break on the shore. These repeated insults can cause a plant or animal\'s structural materials to fatigue and fail, even though no single force would be sufficient to break the organism. Indeed, the survivorship and maximum size of at least one species of seaweed is set by the accumulated effects of small forces rather than the catastrophic imposition of a single lethal force. One might suppose that fatigue would be especially potent in articulated coralline algae, in which the strain of the entire structure is concentrated in localized joints, the genicula. However, previous studies of joint morphology suggest an alternative hypothesis. Each geniculum is composed of a single tier of cells, which are attached at their ends to the calcified segments of the plant (the intergenicula) but have minimal connection to each other along their lengths. This lack of neighborly attachment potentially allows the weak interfaces between cells to act as \'crack stoppers\', inhibiting the growth of fatigue cracks. We tested this possibility by repeatedly loading fronds of Calliarthron cheilosporioides, a coralline alga common on wave-washed shores in California. When repeatedly loaded to 50-80% of its breaking strength, C. cheilosporioides commonly survives more than a million stress cycles, with a record of 51 million. We show how this extraordinary fatigue resistance interacts with the distribution of wave-induced water velocities to set the limits to size in this species.