Tailoring spontaneous infrared emission of HgTe quantum dots with laser-printed plasmonic arrays.

Chemically synthesized near-infrared to mid-infrared (IR) colloidal quantum dots (QDs) offer a promising platform for the realization of devices including emitters, detectors, security, and sensor systems. However, at longer wavelengths, the quantum yield of such QDs decreases as the radiative emission rate drops following Fermi's golden rule, while non-radiative recombination channels compete with light emission. Control over the radiative and non-radiative channels of the IR-emitting QDs is crucially important to improve the performance of IR-range devices. Here, we demonstrate strong enhancement of the spontaneous emission rate of near- to mid-IR HgTe QDs coupled to periodically arranged plasmonic nanoantennas, in the form of nanobumps, produced on the surface of glass-supported Au films via ablation-free direct femtosecond laser printing. The enhancement is achieved by simultaneous radiative coupling of the emission that spectrally matches the first-order lattice resonance of the arrays, as well as more efficient photoluminescence excitation provided by coupling of the pump radiation to the local surface plasmon resonances of the isolated nanoantennas. Moreover, coupling of the HgTe QDs to the lattice plasmons reduces the influence of non-radiative decay losses mediated by the formation of polarons formed between QD surface-trapped carriers and the IR absorption bands of dodecanethiol used as a ligand on the QDs, allowing us to improve the shape of the emission spectrum through a reduction in the spectral dip related to this ligand coupling. Considering the ease of the chemical synthesis and processing of the HgTe QDs combined with the scalability of the direct laser fabrication of nanoantennas with tailored plasmonic responses, our results provide an important step towards the design of IR-range devices for various applications.

Ex-vivo haemodynamic models for the study of Stanford type B aortic dissection in isolated porcine aorta.

OBJECTIVES: The aim of this study is to present novel ex-vivo models in the study of complex haemodynamical changes in Stanford type B aortic dissection (TBAD). MATERIALS AND METHODS: Fifteen fresh porcine aortas were harvested and preserved with 4 °C saline. Ex-vivo models were developed to simulate TBAD in three different situations: model A with patent false lumen, model B with distal re-entry only and model C with proximal primary entry only. These models were connected to standardised pulsatile pumps and the pressure waveforms were monitored and compared. The aortas were scanned with ultrasonography and subjected to post-experiment autopsy. RESULTS: The three different models were successfully created (n = 13). Pulsatile flow testing was successful and the shapes of the pressure waveforms were similar to those taken from human aorta. Post-testing gross examination confirmed the success of modelling. CONCLUSION: Porcine aortas may prove to be useful ex-vivo models in the study of aortic dissection haemodynamics. These models are reproducible and may be used in the study of complex haemodynamic forces during the development and propagation of TBAD. Our three porcine models give a potential possibility in helping clinicians isolate and analyse complex haemodynamical factors in the development, propagation and prognosis of TBAD.

Successful emergency endovascular treatment of juxtarenal and infrarental mycotic aortic aneurysms in patients with small diameter aortae using Cook(®) Zenith ESLE Stentgrafts.

BACKGROUND: Endovascular repair of mycotic aneurysm is an alternative to open repair if the patho-anatomy is suitable. The aortic size above and below the mycotic aneurysm may be small. METHODS: A retrospective review was made of prospectively collected departmental computerised database. RESULTS: Three oriental patients with juxta- and infra-renal mycotic aortic aneurysms with a small aortic diameter of 17 mm to 18 mm underwent successful emergency endovascular treatment using Cook(®) Zenith ESLE stentgrafts. These are ancillary devices aimed at iliac extensions usually. CONCLUSION: This is to our knowledge the first case series of Cook(®) Zenith ESLE iliac component endografts for the treatment of aortic mycotic aneurysms with small aortae, and short- and mid-term results are encouraging.

Endovascular repair for abdominal aortic aneurysms: the first hundred cases.

OBJECTIVE: To evaluate the early and mid-term results of the first 100 elective endovascular repairs for abdominal aortic aneurysms. DESIGN: Retrospective analysis of prospectively collected data. SETTING: University teaching hospital, Hong Kong. PATIENTS: The first 100 patients with infrarenal abdominal aortic aneurysms who underwent elective endovascular repair. MAIN OUTCOME MEASURES: Peri-operative data, mortality and morbidities as well as the follow-up details were recorded. Cumulative data on endoleaks, clinical failures, secondary procedures, and survival were evaluated with Kaplan-Meier analyses. RESULTS: There were 85 men and 15 women, with a mean age of 75 (range, 50-90) years. Failed implantations due to access difficulty occurred in two patients during the same period, giving a technical success rate of 98%. The mean aneurysm diameter was 6.2 cm. Access site injury requiring repair occurred in four (4%) of the patients, while wound problems were the most common complications (11%). The median hospital stay was 6 days, and there were two hospital deaths, giving a hospital mortality rate of 2%. During a mean follow-up of 36 (standard deviation, 24) months, there were three aneurysmal ruptures and four elective open conversions, with only one aneurysm-related death after hospital discharge. At 3 years, the cumulative rates of freedom from any endoleak, freedom from primary failure, freedom from secondary failure, freedom from secondary procedures, and survival were 60%, 84%, 89%, 88%, and 78%, respectively. CONCLUSIONS: The early and mid-term results of elective endovascular repair for abdominal aortic aneurysms appear promising. The procedure is effective in preventing aneurysm-related death in the mid-term. Nevertheless, the importance of constant surveillance cannot be over-emphasised, as clinical failures and ruptures are still a concern.