188 research outputs found
Effects of enriched artemia on growth and survival of juvenile freshwater crayfish (Astacus leptodactylus Esch. 1823)
The experiment was conducted to investigate the effects of artemia enriched with lipid emulsions containing highly unsaturated fatty acids on growth and survival of juvenile freshwater crayfish Astacus leptodactylus. Juvenile crayfish were fed artemia enriched with commercial emulsions (red pepper and olio ω3) and un-enriched artemia (control). The highest eicosapentaenoic acid (EPA) level was found in artemia enriched with olio ω3 (3.17%) and the highest docosahexaenoic acid (DHA) level was found in artemia enriched with red pepper (3.56%). The weight gain, specific growth, and survival rates of juvenile crayfish increased with increasing amount of EPA and DHA in dietary artemia respectively (0.04%, 2.32%). Finally, the juveniles fed with artemia enriched with olio ω3 and red pepper had a better weight gain, specific growth rate, and survival than those fed with un-enriched artemia (p<0.05)
Experimental validation of a modeling framework for upconversion enhancement in 1D-photonic crystals
Photonic structures can be designed to tailor luminescence properties of materials, which becomes particularly interesting for non-linear phenomena, such as photon upconversion. However, there is no adequate theoretical framework to optimize photonic structure designs for upconversion enhancement. Here, we present a comprehensive theoretical model describing photonic effects on upconversion and confirm the model’s predictions by experimental realization of 1D-photonic upconverter devices with large statistics and parameter scans. The measured upconversion photoluminescence enhancement reaches 82 ± 24% of the simulated enhancement, in the mean of 2480 separate measurements, scanning the irradiance and the excitation wavelength on 40 different sample designs. Additionally, the trends expected from the modeled interaction of photonic energy density enhancement, local density of optical states and internal upconversion dynamics, are clearly validated in all experimentally performed parameter scans. Our simulation tool now opens the possibility of precisely designing photonic structure designs for various upconverting materials and applications
Photoelectrical reading in ZnO/Si NCs/p-Si resistive switching devices
The increasing need for efficient memories with integrated functionalities in a single device has led the electronics community to investigate and develop different materials for resistive switching (RS) applications. Among these materials, the well-known Si nanocrystals (NCs) have demonstrated to exhibit RS properties, which add to the wealth of phenomena that have been studied on this model material platform. In this work, we present ZnO/Si NCs/p-Si resistive switching devices whose resistance state can be electrically read at 0 V under the application of low-power monochromatic illumination. The presented effect is studied in terms of the inner structural processes and electronic physics of the device. In particular, the creation of conductive filaments through the Si NC multilayers induces a low-resistance path for photogenerated carriers to get extracted from the device, whereas in the pristine state charge extraction is strongly quenched due to the insulating nature of the NC-embedding SiO2 matrix. In addition, spectral inspection of the generated photocurrent allowed unveiling the role of Si NCs in the reported effect. Overall, the hereby shown results pave the way to obtain memories whose RS state can be read under low-power conditions
Modulation of CD8\u3csup\u3e+\u3c/sup\u3e T cell responses to AAV vectors with IgG-derived MHC class II epitopes
Immune responses directed against viral capsid proteins constitute a main safety concern in the use of adeno-associated virus (AAV) as gene transfer vectors in humans. Pharmacological immunosuppression has been proposed as a solution to the problem; however, the approach suffers from several potential limitations. Using MHC class II epitopes initially identified within human IgG, named Tregitopes, we showed that it is possible to modulate CD8+ T cell responses to several viral antigens in vitro. We showed that incubation of peripheral blood mononuclear cells with these epitopes triggers proliferation of CD4+CD25+FoxP3+ T cells that suppress killing of target cells loaded with MHC class I antigens in an antigen- specific fashion, through a mechanism that seems to require cell-to-cell contact. Expression of a construct encoding for the AAV capsid structural protein fused to Tregitopes resulted in reduction of CD8+ T cell reactivity against the AAV capsid following immunization with an adenoviral vector expressing capsid. This was accompanied by an increase in frequency of CD4+CD25+FoxP3+ T cells in spleens and lower levels of inflammatory infiltrates in injected tissues. This proof-of-concept study demonstrates modulation of CD8+ T cell reactivity to an antigen using regulatory T cell epitopes is possible
Lung Transplantation for Primary Ciliary Dyskinesia and Kartagener Syndrome: A Multicenter Study.
Primary ciliary dyskinesia, with or without situs abnormalities, is a rare lung disease that can lead to an irreversible lung damage that may progress to respiratory failure. Lung transplant can be considered in end-stage disease. This study describes the outcomes of the largest lung transplant population for PCD and for PCD with situs abnormalities, also identified as Kartagener's syndrome. Retrospectively collected data of 36 patients who underwent lung transplantation for PCD from 1995 to 2020 with or without SA as part of the European Society of Thoracic Surgeons Lung Transplantation Working Group on rare diseases. Primary outcomes of interest included survival and freedom from chronic lung allograft dysfunction. Secondary outcomes included primary graft dysfunction within 72 h and the rate of rejection ≥A2 within the first year. Among PCD recipients with and without SA, the mean overall and CLAD-free survival were 5.9 and 5.2 years with no significant differences between groups in terms of time to CLAD (HR: 0.92, 95% CI: 0.27-3.14, p = 0.894) or mortality (HR: 0.45, 95% CI: 0.14-1.43, p = 0.178). Postoperative rates of PGD were comparable between groups; rejection grades ≥A2 on first biopsy or within the first year was more common in patients with SA. This study provides a valuable insight on international practices of lung transplantation in patients with PCD. Lung transplantation is an acceptable treatment option in this population
Silicon nanocrystals-based electroluminescent resistive switching device
In the last few years, the emergence of studies concerning the resistive switching (RS) phenomenon has resulted in the finding of a large amount of materials being capable of acting as an active layer in such devices, i.e., the layer where the change in resistance takes place. Whereas the normal operation consists of the electrical readout of the modified resistance state of the device after electrical writing, electro-photonic approaches seek the involvement of light in these devices, be it either for the active Set or Reset operations or the readout. We propose in this work silicon nanocrystal multilayers (Si NC MLs) as an active material for being used in RS devices, taking advantage of their outstanding optical properties. The resistance states of Si NC MLs were obtained by electrical excitation, whose readout is carried out by electrical and electro-optical means, thanks to a distinguishable electroluminescence emission under each state. To achieve this, we report on an adequate design that combines both the Si NC MLs with ZnO as a transparent conductive oxide, whose material properties ensure the device RS performance while allowing the electro-optical characterization. Overall, such an occurrence states the demonstration of a Si NCs-based electroluminescent RS device, which paves the way for their future integration into photonic integrated circuits
A high-performance 8 nV/root Hz 8-channel wearable and wireless system for real-time monitoring of bioelectrical signals
Background: It is widely accepted by the scientific community that bioelectrical signals, which can be used for the identification of neurophysiological biomarkers indicative of a diseased or pathological state, could direct patient treatment towards more effective therapeutic strategies. However, the design and realisation of an instrument that can precisely record weak bioelectrical signals in the presence of strong interference stemming from a noisy clinical environment is one of the most difficult challenges associated with the strategy of monitoring bioelectrical signals for diagnostic purposes. Moreover, since patients often have to cope with the problem of limited mobility being connected to bulky and mains-powered instruments, there is a growing demand for small-sized, high-performance and ambulatory biopotential acquisition systems in the Intensive Care Unit (ICU) and in High-dependency wards. Finally, to the best of our knowledge, there are no commercial, small, battery-powered, wearable and wireless recording-only instruments that claim the capability of recording electrocorticographic (ECoG) signals. Methods: To address this problem, we designed and developed a low-noise (8 nV/√Hz), eight-channel, battery-powered, wearable and wireless instrument (55 × 80 mm2). The performance of the realised instrument was assessed by conducting both ex vivo and in vivo experiments. Results: To provide ex vivo proof-of-function, a wide variety of high-quality bioelectrical signal recordings are reported, including electroencephalographic (EEG), electromyographic (EMG), electrocardiographic (ECG), acceleration signals, and muscle fasciculations. Low-noise in vivo recordings of weak local field potentials (LFPs), which were wirelessly acquired in real time using segmented deep brain stimulation (DBS) electrodes implanted in the thalamus of a non-human primate, are also presented. Conclusions: The combination of desirable features and capabilities of this instrument, namely its small size (~one business card), its enhanced recording capabilities, its increased processing capabilities, its manufacturability (since it was designed using discrete off-the-shelf components), the wide bandwidth it offers (0.5 – 500 Hz) and the plurality of bioelectrical signals it can precisely record, render it a versatile and reliable tool to be utilized in a wide range of applications and environments
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