Photoelectrochemical fabrication of spectroscopic diffraction gratings

Photoelectrochemical etching was demonstrated as a means of fabricating a variety of periodic structures in semiconductors. The semiconductor is used as an electrode in an electrochemical cell, and is in contact with a liquid electrolyte. When the crystal is held at a positive voltage and illuminated, etching occurs in only the illuminated regions to a depth proportional to the illumination intensity and exposure time. In Phase 1, it was determined that diffraction gratings could be produced in gallium arsenide crystals by this method, using either a scanned focused laser beam or by uniform illumination of a ruling mask defined in metal or photoresist on the crystal surface. The latter approach was determined to produce V-grooves if the mask is oriented along certain crystallographic directions. These V-grooves were produced with an exceedingly smooth crystal morphology due to the highly controllable nature of the process and the mild electrolytes involved. The results form the basis for photoelectrochemical fabrication of deep, low pitch Eschelle gratings for use in high orders in NASA spectrographic instrumentation such as the Space Telescope Imaging Spectrograph

Photoelectrochemical fabrication of spectroscopic diffraction gratings, phase 2

This program was directed toward the production of Echelle diffraction gratings by a light-driven, electrochemical etching technique (photoelectrochemical etching). Etching is carried out in single crystal materials, and the differential rate of etching of the different crystallographic planes used to define the groove profiles. Etching of V-groove profiles was first discovered by us during the first phase of this project, which was initially conceived as a general exploration of photoelectrochemical etching techniques for grating fabrication. This highly controllable V-groove etching process was considered to be of high significance for producing low pitch Echelles, and provided the basis for a more extensive Phase 2 investigation

La biodiversità

Il tema ci consente di affrontare l’evoluzione del rapporto tra terra e alimentazione, osservando i cambiamenti che hanno interessato le tecniche di produzione e l’attenzione ai problemi legati alla salute e alla tutela dell’ambiente. La vita delle generazioni passate ha sempre avuto come unico centro di riferimento la terra ed i suoi frutti: possedere un appezzamento di terra costituiva una enorme ricchezza perché garantiva il necessario sostentamento per una o più famiglie. La presenza di animali da cortile o di bestiame forniva un contributo allo svolgimento delle attività nei campi e consentiva di variare i pasti da presentare a tavola. Il rapporto del cibo con la terra era diretto, non subiva alcun tipo di passaggio, se non per raggiungere il mercato o la fiera dei paesi limitrofi, dove si proponevano la frutta e la verdura di stagione, il latte prodotto in eccedenza rispetto al fabbisogno domestico, le uova o la carne macellata direttamente dall’allevatore, sebbene molto più raramente

ANEMIA OF INFLAMMATION: INVESTIGATION ON HEPCIDIN IN ACUTELY ILL PATIENTS AND THEIR CLINICAL OUTCOME

The anaemia of inflammation is a normochromic, normocytic anaemia, associated with abnormal iron utilization, erythropoietin hyporesponsiveness, and decreased red blood cells (RBC) survival. It is a very common problem in hospitalized patients for acute inflammatory diseases and develops within few days from the onset of illness. Hepcidin is an interleukin-6 induced hormone previously identified as an antimicrobial peptide. Now it is recognized as the master regulator of iron homeostasis in mammals allowing iron adaptation according to the body iron needs and as the key modulator of inflammation-associated anaemia. Hepcidin is found in the circulation, it is secreted mainly by hepatocytes and to a lesser extent by macrophages, T-lymphocytes and adipocytes. In 60 acutely ill patients (95% affected by infections), the degree of inflammation, indicated by IL-6 and C-RP levels, is associated with elevated concentrations of hepcidin, low iron serum levels, high transferrin saturation and very high ferritin serum levels. Moreover, persistently increased levels of hepcidin-25 on T1 and on T6 are associated with a decrease in haemoglobin during hospitalization. Patients (N=26) anaemic on T1 were still anaemic after one week. Erythropoiesis was still blunted in these patients, despite higher erythropoietin serum levels than notanaemic patients. The high levels of GDF-15 and hepcidin could have a role in the ineffective erythropoiesis. We observed that acute ill patients (N=31) admitted with normal haemoglobin levels develop anaemia after the first week of hospitalization. Analysing hepcidin levels of this subset of patients, we found that a cut-off level of hepcidin concentration of 23 nM/L was able to predict anaemia occurrence after one week with 100% of sensitivity and 90% of specificity. The inflammatory cytokines pattern and its consequence on hepcidin and iron observed in vivo in this study resembles the one described in experimental models of endotoxemia showed by Kemna et al. and by Theurl et al. Also hepcidin serum levels, haemoglobin and iron parameters are very similar to the ones found by van Eijk et al. in their investigation in septic patients admitted to intensive care units. As described in previous studies, we also demonstrated expression of hepcidin mRNA in circulating monocytes of these acutely ill patients. We found that the higher was the inflammation on admission, the higher was hepcidin mRNA expression in circulating monocytes after one week. Moreover we found negative correlation between mRNA levels of monocytes-derived hepcidin and serum ferritin, especially after one week of inflammation persistence. Analysis of interleukin-6 functional receptor (CD126 and gp130) on circulating monocytes showed a negative correlation with monocytes-derived hepcidin mRNA, and positive correlation with serum ferritin levels. These insights in anaemia of inflammation molecular mechanisms will help clinicians to better identify anaemia causes and adequately restore haemoglobin concentration with target therapies, reducing health-care requirements and healthcare costs, in-hospital stay and, finally, ameliorate health of patients

Coronary Revascularization in Patients With Stable Coronary Artery Disease: The Role of Imaging

: In the last decades, the effective management of some cardiovascular risk factors in the general population has led to a progressive decrease in the prevalence of coronary artery disease (CAD). Nevertheless, coronary heart disease remains the major cause of death in developed and developing countries and chronic coronary syndromes (CCS) are still a major target of utilization of non-invasive cardiac imaging and invasive procedures. Current guidelines recommend the use of non-invasive imaging in patients with CCS to identify subjects at higher risk to be referred for invasive coronary angiography and possible revascularization. These recommendations are challenged by two opposite lines of evidence. Recent trials have somewhat questioned the efficacy of coronary revascularization as compared with optimal medical therapy in CCS. As a consequence the role of imaging in these patients and in in patients with ischemic cardiomyopathy is under debate. On the other hand, real-life data indicate that a consistent proportion of patients undergo invasive procedure and are revascularized without any previous non-invasive imaging characterization. On top of this, the impact of COVID-19 pandemic on the sanitary systems caused a change in the current management of patients with CAD. In the present review we will discuss these conflicting data analyzing the evidence which has been recently accumulated as well as the gaps of knowledge which should still be filled

Health-Related Quality of Life in Patients with CVID Under Different Schedules of Immunoglobulin Administration: Prospective Multicenter Study

We assessed the health-related quality of life (HRQoL) in CVID adults receiving different schedules of immunoglobulin replacement therapy (IgRT) by intravenous (IVIG), subcutaneous (SCIG), and facilitated (fSCIG) preparations. For these patients, IgRT schedule was chosen after a period focused on identifying the most suitable individual option

Current Strategies for the manufacture of Small Size Tissue Engineering Vascular Graft

Occlusive arterial disease, including coronary heart disease (CHD) and peripheral arterial disease (PAD), is the main cause of death, with an annual mortality incidence predicted to rise to 23.3 million worldwide by 2030. Current revascularization techniques consist of angioplasty, placement of a stent, or surgical bypass grafting. Autologous vessels, such as the saphenous vein and internal thoracic artery, represent the gold standard grafts for small-diameter vessels. However, they require invasive harvesting and are often unavailable. Synthetic vascular grafts represent an alternative to autologous vessels. These grafts have shown satisfactory long-term results for replacement of large- and medium-diameter arteries, such as the carotid or common femoral artery, but have poor patency rates when applied to small-diameter vessels, such as coronary arteries and arteries below the knee. Considering the limitations of current vascular bypass conduits, a tissue-engineered vascular graft (TEVG) with the ability to grow, remodel, and repair in vivo presents a potential solution for the future of vascular surgery. Here, we review the different methods that research groups have been investigating to create TEVGs in the last decades. We focus on the techniques employed in the manufacturing process of the grafts and categorize the approaches as scaffold-based (synthetic, natural, or hybrid) or self-assembled (cell-sheet, microtissue aggregation and bioprinting). Moreover, we highlight the attempts made so far to translate this new strategy from the bench to the bedside