Sex disparities in popliteal artery aneurysms.

OBJECTIVE: Only 5% of patients with popliteal artery aneurysms (PAAs) are female. Evidence on PAA treatment and outcomes in women is therefore scarce. The POPART Registry provides one of Europe's largest data collections regarding PAA treatment. Data on clinical presentation, aneurysm morphology, and perioperative outcomes after open surgical PAA repair in women will be presented. METHODS: POPART is a multicenter, noninterventional registry for open and endovascular PAA repair, with 42 participating centers in Germany and Luxembourg. All patients aged >18 years who have been treated for PAA since 2010 are eligible for study inclusion. Data collection is based on an online electronic case report form. RESULTS: Of the 1236 PAAs, 58 (4.8%) were in women. There were no significant differences in age or cardiopulmonary comorbidities. However, female patients had a lower prevalence of contralateral PAAs and abdominal aortic aneurysms (P < .05). PAAs in women were more likely to be symptomatic before surgery (65.5% vs 49.4%; P = .017), with 19% of women presenting with acute limb ischemia (vs 11%; P = .067). Women had smaller aneurysm diameters than men (22.5 mm vs 27 mm; P = .004) and became symptomatic at smaller diameters (20 mm vs 26 mm; P = .002). Only 8.6% of women and 11.6% of men underwent endovascular aneurysm repair (P > .05); therefore, the perioperative outcome analysis focused on open surgical repair. In total, 23.5% of women and 16.9% of men developed perioperative complications (P > .05). There were no differences in major cardiovascular events (P > .05), but women showed a higher incidence of impaired wound healing (15.7% vs 7.2%; P = .05) and major amputation (5.9% vs 1.1%; P = .027). Female sex was significantly associated with the need for nonvascular reinterventions within 30 days after surgery (odds ratio: 2.48, 95% confidence interval: 1.26-4.88), whereas no significant differences in the odds for vascular reinterventions were observed (odds ratio: 1.98, 95% confidence interval: 0.68-5.77). In the multiple logistic regression model, female sex, symptomatic PAAs, poor quality of outflow vessels, and graft material other than vein graft were independently associated with perioperative reinterventions. CONCLUSIONS: Women have smaller PAAs, are more likely to be symptomatic before treatment, and are more often affected by nonvascular reinterventions in the perioperative course. As our understanding of aneurysmatic diseases in women continues to expand, sex-specific treatment strategies and screening options for women in well-selected cohorts with modified screening protocols should be continuously re-evaluated.

Hardness Assessment Considering Nitrided Layers Based on Tempering Tests for Numerical Wear Prediction for Forging Processes.

The nitriding of forging tools is an industrially established standard used to increase the hardness of the tool surface layer and reduce wear. However, this modification of the tool surface layer, as well as the microstructural changes that occur during this operation due to the thermo-mechanical load, cannot be considered during wear calculations with the widely used Archard wear model in the context of FE simulations. Based on previous work, this study further develops two tempering tests for the investigation of the hardness evolution of two nitride profiles based on H11 tool steel. Here, significant tempering effects could be observed depending on temperature, mechanical stress superposition and time. The results are used for setting up a new material model that is implemented in an existing numerical wear model. The validation is carried out in two laboratory forging test series. The evaluation shows that the hardness development in terms of tempering effects of a nitrided forging tool can be numerically predicted, especially for high forging cycles. However, due to the unexpected occurrence of adhesion effects, only limited applicability of the wear prediction then carried out is achieved.

Ceramic-Reinforced γ-TiAl-Based Composites: Synthesis, Structure, and Properties.

In this study, new multilayer TiAl-based composites were developed and characterized. The materials were produced by spark plasma sintering (SPS) of elemental Ti and Al foils and ceramic particles (TiB2 and TiC) at 1250 °C. The matrix of the composites consisted of α2-TiAl and γ-TiAl lamellas and reinforcing ceramic layers. Formation of the α2 + γ structure, which occurred via a number of solid⁻liquid and solid⁻solid reactions and intermediate phases, was characterized by in situ synchrotron X-ray diffraction analysis. The combination of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis revealed that an interaction of TiC with Ti and Al led to the formation of a Ti2AlC Mn+1AXn (MAX) phase. No chemical reactions between TiB2 and the matrix elements were observed. The microhardness, compressive strength, and creep behavior of the composites were measured to estimate their mechanical properties. The orientation of the layers with respect to the direction of the load affected the compressive strength and creep behavior of TiC-reinforced composites. The compressive strength of samples loaded in the perpendicular direction to layers was higher; however, the creep resistance was better for composites loaded in the longitudinal direction. The microhardness of the composites correlated with the microhardness of reinforcing components.

Potentiation of nociceptive responses to low pH injections in humans by prostaglandin E2.

UNLABELLED: Inflammation and trauma lead to tissue acidification and release of inflammatory mediators, including prostaglandin E2 (PGE2). Protons can evoke pain through acid-sensing ion channels (ASICs) and TRPV1 receptors. In this study, we examined whether PGE2 can potentiate proton-induced nociception in humans on injection into skin and muscle. Psychophysical and vascular responses to microinjections of protons (pH 6.0 and 6.5), PGE2 (10-6 and 10-7 M) and their combinations into forearm skin (30 microL) or anterior tibial muscle (50 microL) were assessed in 16 male subjects. Pain intensity, axon reflex erythema, and heat pain thresholds were recorded after skin challenge; pain intensity and thresholds for pressure-evoked pain were recorded after intramuscular injections. Intradermal or intramuscular injections of PGE2 induced very low levels of pain similar to saline. Administration of low pH caused moderate pain within 5 seconds that declined rapidly over 15 to 20 seconds. In comparison, coinjection of low pH with PGE2 led to a biphasic profile of the pain response. Combined pH + PGE2 stimulation provoked significantly increased pain in the second phase after injections (20 to 100 seconds) both in skin and muscle, whereas the initial injection pain was not enhanced. Heat pain thresholds were reduced after PGE2 and combined pH + PGE2, whereas flare responses were rather attenuated on coadministration of low pH with PGE2. Intriguingly, when compared with skin, muscle pain was significantly lower in the initial phase (0 to 15 seconds) but significantly higher in the second phase (20 to 100 seconds after injection). PERSPECTIVE: PGE2 can potentiate nociceptor activation by protons in human skin and muscle, indicated by increased sustained pain ratings. This can be best explained by TRPV1 sensitization in the presence of PGE2, a mechanism potentially relevant for inflammatory and injury-induced pain.