Unveiling quantum-limited operation of interband cascade lasers

A comprehensive experimental analysis of the frequency fluctuations of a mid-infrared interband cascade laser, down to the quantum-limited operation, is reported. These lasers differ from any other class of semiconductor lasers in their structure and internal carrier generation and transport processes. Although already commercially available, a full evaluation of their potential has not been possible, until now, mainly because their internal dynamics are not yet understood well enough. The measured intrinsic linewidth, down to 10 kHz, ranks them in between quantum cascade and bipolar semiconductor lasers. Understanding the noise features is especially important for demanding applications and is a necessary step for a deeper knowledge of the physical behavior for this class of lasers, in view of the development of novel designs for improved performance.A comprehensive experimental analysis of the frequency fluctuations of a mid-infrared interband cascade laser, down to the quantum-limited operation, is reported. These lasers differ from any other class of semiconductor lasers in their structure and internal carrier generation and transport processes. Although already commercially available, a full evaluation of their potential has not been possible, until now, mainly because their internal dynamics are not yet understood well enough. The measured intrinsic linewidth, down to 10 kHz, ranks them in between quantum cascade and bipolar semiconductor lasers. Understanding the noise features is especially important for demanding applications and is a necessary step for a deeper knowledge of the physical behavior for this class of lasers, in view of the development of novel designs for improved performance

Prunus persica var. platycarpa (Tabacchiera Peach): bioactive compounds and antioxidant activity of pulp, peel and seed ethanolic extracts

A comparative analysis of ethanol extracts from peel, pulp and seed of Prunus persica var. platycarpa (Tabacchiera peach) was done. The total phenols, flavonoids and carotenoids content as well as the antioxidant properties were evaluated. Peach pulp extract was characterized by the highest total phytonutrients content and exhibited the highest antioxidant activity in all in vitro assays. Interestingly, pulp extract showed IC50 values of 2.7 and 2.2 g/mL at 30 and 60 minutes of incubation, respectively using -carotene bleaching test. A remarkable result was also obtained by using Fe-chelating assay (IC50 of 2.9 g/mL vs 1.3 g/mL for positive control BHT). Pulp extract was subjected to liquid chromatography-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS). Six main compounds, namely gallic acid, protocatechuic acid, protocatechualdehyde, chlorogenic acid, p-coumaric acid, and ferulic acid, were identified. Overall, the results suggest that Prunus persica var. platycarpa displays a good antioxidant activity and its consumption could be promote

Real-time terahertz digital holography with a quantum cascade laser

Coherent imaging in the THz range promises to exploit the peculiar capabilities of these wavelengths to penetrate common materials like plastics, ceramics, paper or clothes with potential breakthroughs in non-destructive inspection and quality control, homeland security and biomedical applications. Up to now, however, THz coherent imaging has been limited by time-consuming raster scanning, point-like detection schemes and by the lack of adequate coherent sources. Here, we demonstrate real-time digital holography (DH) at THz frequencies exploiting the high spectral purity and the mW output power of a quantum cascade laser combined with the high sensitivity and resolution of a microbolometric array. We show that, in a one-shot exposure, phase and amplitude information of whole samples, either in reflection or in transmission, can be recorded. Furthermore, a 200 times reduced sensitivity to mechanical vibrations and a significantly enlarged field of view are observed, as compared to DH in the visible range. These properties of THz DH enable unprecedented holographic recording of real world dynamic scenes

Retrieval of phase relation and emission profile of quantum cascade laser frequency combs

The major development recently undergone by quantum cascade lasers has effectively extended frequency comb emission to longer-wavelength spectral regions, i.e. the mid and far infrared. Unlike classical pulsed frequency combs, their mode-locking mechanism relies on four-wave mixing nonlinear processes, with a temporal intensity profile different from conventional short-pulses trains. Measuring the absolute phase pattern of the modes in these combs enables a thorough characterization of the onset of mode-locking in absence of short-pulses emission, as well as of the coherence properties. Here, by combining dual-comb multi-heterodyne detection with Fourier-transform analysis, we show how to simultaneously acquire and monitor over a wide range of timescales the phase pattern of a generic frequency comb. The technique is applied to characterize a mid-infrared and a terahertz quantum cascade laser frequency comb, conclusively proving the high degree of coherence and the remarkable long-term stability of these sources. Moreover, the technique allows also the reconstruction of electric field, intensity profile and instantaneous frequency of the emission.Comment: 20 pages. Submitted to Nature Photonic

Argonaute 2 drives miR-145-5p-dependent gene expression program in breast cancer cells

To perform their regulatory functions, microRNAs (miRNAs) must assemble with any of the four mammalian Argonaute (Ago) family of proteins, Ago1–4, into an effector complex known as the RNA-induced silencing complex (RISC). While the mature miRNA guides the RISC complex to its target mRNA, the Ago protein represses mRNA translation. The specific roles of the various Ago members in mediating miRNAs activity, however, haven’t been clearly established. In this study, we investigated the contribution of Ago2, the only human Ago protein endowed with nuclease activity, to the function of tumor-suppressor miR-145-5p in breast cancer (BC). We show that miR-145-5p and Ago2 protein are concomitantly downregulated in BC tissues and that restoration of miR-145-5p expression in BC cells leads to Ago2 protein induction through the loosening of Ago2 mRNA translational repression. Functionally, miR-145-5p exerts its inhibitory activity on cell migration only in presence of Ago2, while, upon Ago2 depletion, we observed increased miR-145/Ago1 complex and enhanced cell motility. Profiling by microarray of miR-145-5p target mRNAs, in BC cells depleted or not of Ago2, revealed that miR-145-5p drives Ago2-dependent and -independent activities. Our results highlight that the Ago2 protein in cancer cells strictly dictates miR-145-5p tumor suppressor activity

Oral Antiplatelet Therapy for Secondary Prevention of Non-Cardioembolic Ischemic Cerebrovascular Events

Stroke is the leading cause of disability and mortality worldwide. After an acute cerebrovascular ischemia, recurrent vascular events, including recurrent stroke or transient ischemic accidents (TIA), occur in around 20% of cases within the first 3 months. In order to minimize this percentage, antiplatelet therapy may play a key role in the management of non-cardioembolic cerebrovascular events. This review will focus on the current evidence of antiplatelet therapies most commonly discussed in practice guidelines and used in clinical practice for the treatment of stroke/TIA complications. The antiplatelet therapies most commonly used and discussed are as follows: aspirin, clopidogrel, and ticagrelor

Exploring the application of Corynebacterium glutamicum single cell protein in the diet of flathead grey mullet (Mugil cephalus): effects on growth performance, digestive enzymes activity and gut microbiota

The capacity of utilising a single cell protein (SCP) ingredient coming from Corynebacterium glutamicum was assessed on adult grey mullet (Mugil cephalus) reared in captive conditions. The experiment was carried out using triplicate groups of grey mullet of 68 g average initial body weight. Three diets, SCP0, SCP10 and SCP20 with increasing inclusion of SCP (0%, 10% and 20%) in substitution of soybean, poultry and fish meal were formulated to contain 30% protein, 10% fat and 18.5 Mj/kg feed of digestible energy. After 113 days, fish fed SCP diets presented significantly lower growth performance and a significant lower activity of the alkaline proteases and aminopeptidases compared to fish fed diet without SCP inclusion. Gut microbiota appeared modulated by SCP inclusion being dominated at the phylum level by Fusobacteria in fish fed SCP0 (51.1%), while in fish fed SCP10 (67.3%) and SCP20 (53.2%) Proteobacteria was dominant. Data evinces a deficiency in the protein utilisation as a cause of the poor growth performance in fish fed the SCP diets. A hypothesis has been proposed that an incomplete SCP cell-wall lysis accounts for this outcome because of the particular organisation of the digestive system of grey mullet (which lack of an acidic stomach digestion) and the failing in the development of a functional gizzard (no access to sand in captive conditions). Even though the outcomes of this research were quite unexpected, they will improve our knowledge on the digestive system of flathead grey mullet and provide some theoretical basis for an improved development of low FM and SBM aquafeed for the species.This research was undertaken as a part of the FEAMP 2014-2020 project, action 3A. Pilot project for the application of techniques and methods aimed at the enhancement and diversification of fish products from Valliculture financed by Emilia Romagna region. Analyses of digestive enzymes conducted at IRTA were supported by the ACUISOST project funded by the Ministerio de Agricultura, Pesca y Alimentación from the Spanish Government and EU Next Generation funds (PRTR).info:eu-repo/semantics/publishedVersio

Presence of Mycobacterium bovis in slaughterhouses and risks for workers

An investigation was carried out to detect the presence of Mycobacterium bovis in slaughterhouses where intradermal tuberculin test positive cattle were slaughtered, and to evaluate the risk of contamination by M. bovis among exposed slaughterhouse workers. Swabs were taken from the carcasses of slaughtered animals showing autoptic signs of non-generalized forms of tuberculosis, thus authorized for free consumption. Swabs were also taken from the hands and clothes of the staff employed in the butchery production line. Environmental samplings were conducted on the slaughterhouse air using filters and air aspiration devices, and on water used to wash the carcasses after slaughter. Samples from the carcasses of healthy animals were also taken on a following slaughtering session. The swabs were analysed by means of Polymerase Chain Reaction for the detection of mycobacteria. M. bovis was detected on meats, on the hands of one worker, and in the washing water. The results obtained from this study confirm that workers are highly exposed to infection by zoonotic tuberculosis, and that cleaning procedures were ineffective in our setting

Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy: A Contemporary Perspective

Alcohol septal ablation is a minimally invasive procedure for the treatment of left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM) who remain symptomatic despite optimal medical therapy. The procedure causes a controlled myocardial infarction of the basal portion of the interventricular septum by the injection of absolute alcohol with the aim of reducing LVOT obstruction and improving the patient's hemodynamics and symptoms. Numerous observations have demonstrated the efficacy and safety of the procedure, making it a valid alternative to surgical myectomy. In particular, the success of alcohol septal ablation depends on appropriate patient selection and the experience of the institution where the procedure is performed. In this review, we summarize the current evidence on alcohol septal ablation and highlight the importance of a multidisciplinary approach involving a team of clinical and interventional cardiologists and cardiac surgeons with high expertise in the management of HOCM patients-the Cardiomyopathy Team