Wavelength-swept Yb-fiber master-oscillator-power-amplifier with 70 nm rapid tuning range

A continuous-wave all-polarization maintaining ytterbium-doped fiber master oscillator power amplifier, with a tuning range of 70 nm addressable at tuning rates of up to 20 nm/ms, is described. Up to 10 W of linearly polarized output was generated with an amplified spontaneous emission content of less than 0.2% throughout the tuning range.

Registration of Alfvén resonances in TCABR tokamak by the scanning reflectometer at sideband frequencies

A frequency scanning O-mode reflectometer was used for studies of plasma density oscillations during local Alfvén wave (LAW) excitation in the Tokamak Chauffage Alfvén Brésilien (TCABR) at the frequency f(A) = 5 MHz. It was found that the spectrum of the reflectometer output signal, which consists mainly of the "beat" frequency f(B), is modified by the LAW excitation, and two additional frequency peaks appear, which are symmetrical in relation to the LAW excitation frequency f = f(A) ± f(B). This result opens the possibility to improve the efficiency of studying the LAW induced density oscillations. The symmetry of these frequency peaks yields the possibility of finding the microwave frequency at which the reflectometer cutoff layer coincides with radial position of the LAW resonance zone in the TCABR tokamak.

p73 deficiency results in impaired self renewal and premature neuronal differentiation of mouse neural progenitors independently of p53

The question of how neural progenitor cells maintain its self-renewal throughout life is a fundamental problem in cell biology with implications in cancer, aging and neurodegenerative diseases. In this work, we have analyzed the p73 function in embryonic neural progenitor cell biology using the neurosphere (NS)-assay and showed that p73-loss has a significant role in the maintenance of neurosphere-forming cells in the embryonic brain. A comparative study of NS from Trp73−/−, p53KO, p53KO;Trp73−/− and their wild-type counterparts demonstrated that p73 deficiency results in two independent, but related, phenotypes: a smaller NS size (related to the proliferation and survival of the neural-progenitors) and a decreased capacity to form NS (self-renewal). The former seems to be the result of p53 compensatory activity, whereas the latter is p53 independent. We also demonstrate that p73 deficiency increases the population of neuronal progenitors ready to differentiate into neurons at the expense of depleting the pool of undifferentiated neurosphere-forming cells. Analysis of the neurogenic niches demonstrated that p73-loss depletes the number of neural-progenitor cells, rendering deficient niches in the adult mice. Altogether, our study identifies TP73 as a positive regulator of self-renewal with a role in the maintenance of the neurogenic capacity. Thus, proposing p73 as an important player in the development of neurodegenerative diseases and a potential therapeutic target.

Force production and spatial arm coordination profile in arm crawl swimming in a fixed position

This study analyzed the relationship between mechanical force production and spatial arm position of the swimming movement for each side of the swimmer. Eight internationally recognized male swimmers performed fix positioned arm only swimming with a dynamometer synchronized with underwater cameras. The upper arm positions (α in side, β in frontal view) and the elbow angles (γ in 3D) were determined at the moment where the force production reached the peak (Fmax) and the maximal values of rate of force development (RFDmax). RFDmax and α values showed significant differences between the sides (P<0.05). To show the motion integration structure of the performance, Multiple Regression Analysis (MRA) was employed separately for both sides. For the criterion variable, the impulse of force (ImpF50%) was calculated. The defined parameters as the mechanical and spatial predictor system were used for the model. The results of the MRA showed that the predictor system yielded the model structure of the variables that explain the criterion variables for ImpF50% by the dominant (P=0.007) and by the nondominant side (P=0.001), respectively. The alternate contribution of the variables to the models can objectively express the performance difference between the two sides of the swimmer.

Improved time-frequency analysis of ASDEX Upgrade reflectometry data using the reassigned spectrogram technique

The spectrogram is one of the best-known time-frequency distributions suitable to analyze signals whose energy varies both in time and frequency. In reflectometry, it has been used to obtain the frequency content of FM-CW signals for density profile inversion and also to study plasma density fluctuations from swept and fixed frequency data. Being implemented via the short-time Fourier transform, the spectrogram is limited in resolution, and for that reason several methods have been developed to overcome this problem. Among those, we focus on the reassigned spectrogram technique that is both easily automated and computationally efficient requiring only the calculation of two additional spectrograms. In each time-frequency window, the technique reallocates the spectrogram coordinates to the region that most contributes to the signal energy. The application to ASDEX Upgrade reflectometry data results in better energy concentration and improved localization of the spectral content of the reflected signals. When combined with the automatic (data driven) window length spectrogram, this technique provides improved profile accuracy, in particular, in regions where frequency content varies most rapidly such as the edge pedestal shoulder.

[Endovascular aneurysms repair: 100 consecutive cases outcome analysis]

OBJECTIVE

To evaluate the effectiveness and clinical outcomes of endovascular aneurysm repair in a single regional centre Methods: The medical records one hundred consecutive patients who underwent elective endovascular repair of nonruptured infra-renal abdominal aortic aneurysm were retrospectively reviewed. The assessed outcomes were all-cause mortality, aneurysm-related mortality, incidence of perioperative complications and reinterventions. Patient demographics and procedure characteristics were also analysed.

RESULTS

The patient's mean age was 74.4 years-old. There was a male preponderance, with only 5 women treated. Two-thirds were American Society of Anesthesiologists (ASA) class ≥3. Loco-regional blockade was the anaesthetic technique most commonly used (65%). There were no perioperative deaths. Medical complications occurred in 10.3% of cases, pulmonary and cardiac being the most frequent. The 30-day reintervention rate was 6.1% (SE: 2.4%). The overall median hospital length of stay was 5 days. At 8 years, all cause mortality was 28.5%(SE: 8.5%) and aneurysm-related death was 1.3% (SE: 1.3%). During the follow-up period, 87.9% (SE: 3.7%) of patients remained free from reintervention

CONCLUSIONS

In our institution, EVAR is associated with no early mortality and significantly good perioperative outcomes such as low rate of systemic complications, minimal blood loss, low rate of postoperative mechanical ventilation use and short hospital stay. Although the high reintervention rate for EVAR has been confirmed in several studies, our study did not find such a high need for secondary procedures. We found a durable benefit since aneurysm-related mortality is very low and late overall survival is similar to other reports. In this study's setting, our findings support endovascular management of large AAAs.

[Hybrid treatment of an aortic arch aneurysm]

Traditional open repair of aortic arch aneurysms is a complex and demanding surgery that requires cardiopulmonary bypass, hypothermia and circulatory arrest, being associated with considerable morbidity and mortality. Even with significant advances in pre-operative assessment and optimization, advanced anaesthetic techniques and intensive care, conventional aortic arch repairs remain amongst the highest risk of across all surgical specialties. Therefore, a hybrid approach with sequential transposition of the supra-aortic branches and endovascular stent-graft placement is a less invasive alternative treatment that opens the indication for repair to more critical patients. We report our institution's first experience in the hybrid surgery of aortic arch aneurysms.

[Supra-aortic trunks occlusive disease: three different treatment approaches]

Unlike carotid bifurcation atherosclerotic stenosis, supra-aortic trunks (SAT) occlusive disease is rare and its revascularization uncommon, accouting for less than 10% of the operations performed on the extracranial brain-irrigating arteries. There are three different treatment approaches: transthoracic, extra-anatomic cervical and endovascular. Endovascular repair is gaining popularity as first-line therapy for proximal lesions with favorable anatomy because of its low morbidity and rare mortality. Extra-anatomic bypass is a safe and durable reconstruction and should be considered in patients with single vessel disease, with cardiopulmonary high-risk or with limited life expectancy. If cardiac surgery is needed, central transthoracic reconstruction is preferable, and the two procedures should be combined. The long-term patency of bypasses with aortic origin, specially when multiple vessels are involved, is superior to other repair techniques. We present three clinical cases that illustrate each of these therapeutic strategies: central brachiocephalic revascularization and synchronous cardiac surgery in a patient with complex SAT atherosclerosis disease; subclavian-carotid transposition for disabling upper limb claudication; and subclavian artery stenting for subclavian-steal syndrome. Surgical approach selection should be based on the individual patient's anatomy and operative risk.