24 research outputs found
Memtransistor Devices Based on MoS 2 Multilayers with Volatile Switching due to Ag Cation Migration
In the recent years, the need for fast, robust, and scalable memory devices have spurred the exploration of advanced materials with unique electrical properties. Among these materials, 2D semiconductors are promising candidates as they combine atomically thin size, semiconductor behavior, and complementary metal-oxide-semiconductor compatibility. Here a three-terminal memtransistor device, based on multilayer MoS2 with ultrashort channel length, that combines the usual transistor behavior of 2D semiconductors with resistive switching memory operation is presented. The volatile switching behavior is explained by the Ag cation migration along the channel surface. An extensive physical and electrical characterization to investigate the fundamental properties of the device, is presented. Finally, a chain-type memory array architecture similar to a NAND flash structure consisting of memtransistors is demonstrated, where the individual memory devices can be selected for write and read, paving the way for high-density, 3D memories based on 2D semiconductors
Reservoir Computing with Charge-Trap Memory Based on a MoS2 Channel for Neuromorphic Engineering
Novel memory devices are essential for developing low power, fast, and accurate in-memory computing and neuromorphic engineering concepts that can compete with the conventional complementary metal-oxide-semiconductor (CMOS) digital processors. 2D semiconductors provide a novel platform for advanced semiconductors with atomic thickness, low-current operation, and capability of 3D integration. This work presents a charge-trap memory (CTM) device with a MoS2 channel where memory operation arises, thanks to electron trapping/detrapping at interface states. Transistor operation, memory characteristics, and synaptic potentiation/depression for neuromorphic applications are demonstrated. The CTM device shows outstanding linearity of the potentiation by applied drain pulses of equal amplitude. Finally, pattern recognition is demonstrated by reservoir computing where the input pattern is applied as a stimulation of the MoS2-based CTMs, while the output current after stimulation is processed by a feedforward readout network. The good accuracy, the low current operation, and the robustness to input random bit flip makes the CTM device a promising technology for future high-density neuromorphic computing concepts
Application of the seven-factor-model of personality to an Italian preschool sample
OBJECTIVE: Advances in dimensional assessment of children in healthy and clinical populations has renewed interest in the study of temperament. Cloninger's Temperament and Character Inventory (TCI) has shown high reliability and internal consistency. Adult and adolescent versions have been translated into a number of languages and validated in cross-cultural studies worldwide. To date only one preschool-TCI-based study has been conducted in early infancy with teachers as observers. The present study is aimed to test an Italian Preschool version of the Temperament and Character Inventory (PsTCI). This is the first replication and the first validation study of TCI on preschoolers with parents as observers. METHODS: 395 preschool children, recruited from pediatric communities and day-care centres throughout Italy, participated in the study. Parents of each child enrolled in the study and completed a PsTCI about the child. Standard psychometric tests of reliability and validation were performed. RESULTS: Exploratory factor analyses demonstrated the presence of distinct domains for temperament and character. TCI dimensions had good internal consistency with Cronbach's alpha ranging values (|0.60|-|0.81|). Gender differences were found for Harm Avoidance (β=-0.186; p≤0.001) and Self-Directedness (β=-0.216; p≤0.01), and accounted for 5-35arm-38-702- of the observed variance. CONCLUSION: The present work suggests the psychological complexity of Cloninger's model and confirms its application in pre-school children from diverse environmental and cultural backgrounds. The results confirm that Cloninger's instrument for temperament and character evaluations can also be used with different observers and highlight the importance of considering cultural and demographic differences in the assessment of temperament and character in preschoolers
In vitro bioaccessibility of phenolic acids from a commercial aleurone-enriched bread compared to a whole grain bread
Wheat aleurone, due to its potentially higher bioaccessibility and bioavailability of
micronutrients and phenolic acids, could represent a useful ingredient in the production of
commonly consumed cereal-based food. The aim of the present study was to investigate the in vitro
bioaccessibility of phenolic acids both from an aleurone-enriched bread and from a whole grain bread.
The two bread samples were firstly characterized for the phenolic acid content. An in vitro digestion
was then performed in order to evaluate the release of phenolic acids. The results obtained suggest
that the bioaccessibility of the phenolic acids in the aleurone-enriched bread is higher than in the
whole grain bread. These in vitro results suggest the potential use of aleurone in the production of
foods, and this may represent an attractive possibility to vehicle nutritionally interesting components
to consumers
Hepatitis B Virus DNA Replication Is Coordinated by Core Protein Serine Phosphorylation and HBx Expression
The hepatitis B virus (HBV) core protein forms the capsid of viral particles and is essential for viral genome DNA replication and maturation. The C terminus of core protein contains three serines at positions 155, 162, and 170, phosphorylation of which is important for viral DNA replication. We demonstrate that the phosphorylation of these serines is stimulated by the viral HBx protein, a regulatory protein that activates signal transduction pathways and viral replication. HBx is therefore shown to stimulate HBV replication by increasing core serine phosphorylation. Mutational, biochemical, and mixing studies of C-terminal core serine mutants demonstrate that multiple serine phosphorylations occur on the same core protein. Mutation of individual core protein serines is shown to inhibit HBV replication at distinct stages corresponding to encapsidation of viral pregenomic RNA, reverse transcription, and restriction to synthesis of specific DNA replicative intermediates. We therefore demonstrate that a primary target of HBV replication that is regulated by HBx protein corresponds to increased phosphorylation of the viral core protein. We also demonstrate that core phosphorylation mediated by HBx promotes sequential progression of viral replication through the assembly of capsids primed for different stages of DNA synthesis