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Many of the workflows in the bio/pharmaceutical industry are done under controlled conditions in cleanrooms. But, are these always designed in the best possible way? The heat distribution in cleanrooms [...]

Neurotransmitter release in chemical synapses is fundamental to diverse brain functions such as motor action, learning, cognition, emotion, perception, and consciousness. Moreover, improper functioning or abnormal release of neurotransmitter is associated with numerous neurological disorders such as epilepsy, sclerosis, schizophrenia, Alzheimer’s disease, and Parkinson’s disease. We have utilized hysteresis engineering in a back-gated MoS2field effect transistor (FET) in order to mimic such neurotransmitter release dynamics in chemical synapses. All three essential features, i.e., quantal, stochastic, and excitatory or inhibitory nature of neurotransmitter release, were accurately captured in our experimental demonstration. We also mimicked an important phenomenon called long-term potentiation (LTP), which forms the basis of human memory. Finally, we demonstrated how to engineer the LTP time by operating the MoS2FET in different regimes. Our findings could provide a critical component toward the design of next-generation smart and intelligent human-like machines and human–machine interfaces.

This article provides a comprehensive review of recent advances in heterostructures of two-dimensional (2-D) layered materials for future electronic and optoelectronic applications. We also discuss the progress in capping heterostructures, where an inert 2-D material serves as a passivation layer and provides environmental stability to the relatively unstable 2-D material. Such capping of heterostructures often enhances the electronic properties (e.g., the carrier mobility) of the active 2-D layer by orders of magnitude. Finally, we elucidate the progress in large-area growth of these heterostructures using various state-of-the-art techniques.

The effect of diameter variation on electrical characteristics of long-channel InAs nanowire metal–oxide–semiconductor field-effect transistors is experimentally investigated. For a range of nanowire diameters, in which significant band gap changes are observed due to size quantization, the Schottky barrier heights between source/drain metal contacts and the semiconducting nanowire channel are extracted considering both thermionic emission and thermally assisted tunneling. Nanowires as small as 10 nm in diameter were used in device geometry in this context. Interestingly, while experimental and simulation data are consistent with a band gap increase for decreasing nanowire diameter, the experimentally determined Schottky barrier height is found to be around 110 meV irrespective of the nanowire diameter. These observations indicate that for nanowire devices the density of states at the direct conduction band minimum impacts the so-called branching point. Our findings are thus distinctly different from bulk-type results when metal contacts are formed on three-dimensional InAs crystals.

In this work, the concept of band-to-band tunneling (BTBT) devices is explored and the benefits of Ge/Si core/shell nanowire heterostructures (NWHs) as a material/geometry-related choice are discussed, namely increased performance accessible by 1D material systems that operate in the quantum capacitance limit (QCL), higher tunneling currents than available to Si-based tunneling structures, and compatibility of Ge/Si platforms with current manufacturing processes. The realization of such devices requires a degenerately doped source with an atomically abrupt source/channel interface. Toward this end, we present the electrical characterization of n+-Si shells around Ge cores that are close to the range suitable for the fabrication of optimized tunneling field effect transistors (TFETs). Specifically, we show that tuning the shell growth temperature from 470 to 600 degC has a significant impact on the morphology and transport properties of the grown Ge/Si core/shell nanowires.

Data from the standardization of the Wechsler Preschool and Primary Scale of Intelligence in Shiraz, Iran (193 girls, 203 boys 4 to 6.5 yr. old) were used to develop a short form. Four subtests (Vocabulary, Arithmetic, Picture Completion, and Block Design) were selected on the basis of their high correlations with Full Scale IQs. The validity coefficients were high and significant. The standard errors for the short form were 4.0 to 6.0 points. The short form classified correctly about 73% of the subjects by category of intelligence but tended to underestimate the IQs of subjects of high intelligence and to overestimate the IQs of subjects with low intelligence. Further work is required.

A Persian form of the Otis Self-administering Tests of Mental Ability, Intermediate Form, was administered to a representative sample of Iranian secondary school pupils (944 boys and 554 girls). Iranian Ss as a group scored strikingly lower than their American counterparts. Boys scored significantly higher than girls both in different grades and across grades. Scores correlated significantly with a past academic performance criterion. Test-retest reliability coefficients over a 2-wk. interval were low relative to those given in the test manual.

85 children were administered a conservation proportion task in which they were to judge the relative fullness of a series of glasses in order to determine functioning at the symbolic level of representation. The results indicate that: (a) as age increases (7 to 9 yr.) the number of children functioning at the symbolic level increases, (b) a majority of 9-yr.-old children did not function at the symbolic level and, (c) the percentage of contradictory errors decreased as age increased.

Retest reliability of the Wechsler Preschool and Primary Scale of Intelligence test scores was performed in Iran using 30 subjects in a time interval of 5 to 6 wk. The results of this analysis suggest that this restandardization of the WPPSI provides a consistent measure of intelligence for application in Iran. Reliability coefficients of .83, .90, and .88 were found for Verbal IQ, Performance IQ, and Full Scale IQ, respectively.