Una Macchina Nozionale per Architetture dei Calcolatori come possibile collegamento tra gli insegnamenti del primo anno della laurea in Informatica

In questo articolo presentiamo un esperimento basato sull’adozione del modello RAM di Cook e Reckhow come macchina nozionale per introdurre il linguaggio macchina RISC-V e di un linguaggio visuale a blocchi per avvicinare i novizi ai concetti di base dell’assembler e delle architetture di calcolo. L’esperimento si `e tenuto nella prima parte del corso di Ar chitetture dei Calcolatori nell’anno accademico 2022/23 con 320 studenti con conoscenze molto eterogenee. La scelta di combinare RISC-V, modello RAM e linguaggio a blocchi `e stata dettata dal tentativo di adottare una macchina nozionale in grado di rappresentare i concetti di base di architetture load-store anche per novizi e dalla quale poter ricostrui re i costrutti che nel corso di Introduzione alla Programmazione venivano nel frattempo presentati attraverso il C++

Ligand of Numb proteins LNX1p80 and LNX2 interactwith the human glycoprotein CD8a and promote itsubiquitylation and endocytosis

E3 ubiquitin ligases give specificity to the ubiquitylation process by selectively binding substrates. Recently, their function has emerged as a crucial modulator of T-cell tolerance and immunity. However, substrates, partners and mechanism of action for most E3 ligases remain largely unknown. In this study, we identified the human T-cell co-receptor CD8 a-chain as binding partner of the ligand of Numb proteins X1 (LNX1p80 isoform) and X2 (LNX2). Both LNX mRNAs were found expressed in T cells purified from human blood, and both proteins interacted with CD8a in human HPB-ALL T cells. By using an in vitro assay and a heterologous expression system we showed that the interaction is mediated by the PDZ (PSD95-DlgA-ZO-1) domains of LNX proteins and the cytosolic C-terminal valine motif of CD8a. Moreover, CD8a redistributed LNX1 or LNX2 from the cytosol to the plasma membrane, whereas, remarkably, LNX1 or LNX2 promoted CD8a ubiquitylation, downregulation from the plasma membrane, transport to the lysosomes, and degradation. Our findings highlight the function of LNX proteins as E3 ligases and suggest a mechanism of regulation for CD8a localization at the plasma membrane by ubiquitylation and endocytosis

Antioxidant Efficacy of Olive By-Product Extracts in Human Colon HCT8 Cells

The production of olive oil is accompanied by the generation of a huge amount of waste and by-products including olive leaves, pomace, and wastewater. The latter represents a relevant environmental issue because they contain certain phytotoxic compounds that may need specific treatments before the expensive disposal. Therefore, reducing waste biomass and valorizing by-products would make olive oil production more sustainable. Here, we explore the biological actions of extracts deriving from olive by-products including olive pomace (OP), olive wastewater (OWW), and olive leaf (OLs) in human colorectal carcinoma HCT8 cells. Interestingly, with the same phenolic concentration, the extract obtained from the OWW showed higher antioxidant ability compared with the extracts derived from OP and OLs. These biological effects may be related to the differential phenolic composition of the extracts, as OWW extract contains the highest amount of hydroxytyrosol and tyrosol that are potent antioxidant compounds. Furthermore, OP extract that contains a higher level of vanillic acid than the other extracts displayed a cytotoxic action at the highest concentration. Together these findings revealed that phenols in the by-product extracts may interfere with signaling molecules that cross-link several intracellular pathways, raising the possibility to use them for beneficial health effects

Radioactivity and Heavy Metals Concentration in Italian (Calabrian) DOC Wines

Wine is an alcoholic drink, largely used to accompany food, with a key role in the protective effects on cardiovascular diseases. This study was developed to investigate radioisotopes and heavy metal content of twenty red, rose and white Italian wines, belonging to controlled origin denomination (DOC) geographic areas of the Calabria region, south of Italy. High Purity Germanium (HPGe) Gamma Spectrometry was employed to evaluate anthropogenic (137Cs) and natural (40K) radionuclides specific activity. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess any possible heavy metals contamination by a comparison between Cu, Zn, Pb, B, As and Cd concentrations with the limits set by the Italian Legislation. Calculated annual effective doses due to the ingestion of investigated samples are under allowable levels (1 mSv/year), thus excluding the risk of ionizing radiation effects on humans. Regarding to the metals concentration, experimental results show that they are lower than the contamination threshold values, thus excluding their presence as pollutants