Mechanical Anisotropy in Two-Dimensional Selenium Atomic Layers.

Two-dimensional (2D) trigonal selenium (t-Se) has become a new member in 2D semiconducting nanomaterial families. It is composed of well-aligned one-dimensional Se atomic chains bonded via van der Waals (vdW) interaction. The contribution of this unique anisotropic nanostructure to its mechanical properties has not been explored. Here, for the first time, we combine experimental and theoretical analyses to study the anisotropic mechanical properties of individual 2D t-Se nanosheets. It was found that its fracture strength and Young's modulus parallel to the atomic chain direction are much higher than along the transverse direction, which was attributed to the weak vdW interaction between Se atomic chains as compared to the covalent bonding within individual chains. Additionally, two distinctive fracture modes along two orthogonal loading directions were identified. This work provides important insights into the understanding of anisotropic mechanical behaviors of 2D semiconducting t-Se and opens new possibilities for future applications.

Field-effect at electrical contacts to two-dimensional materials.

The inferior electrical contact to two-dimensional (2D) materials is a critical challenge for their application in post-silicon very large-scale integrated circuits. Electrical contacts were generally related to their resistive effect, quantified as contact resistance. With a systematic investigation, this work demonstrates a capacitive metal-insulator-semiconductor (MIS) field-effect at the electrical contacts to 2D materials: The field-effect depletes or accumulates charge carriers, redistributes the voltage potential, and gives rise to abnormal current saturation and nonlinearity. On one hand, the current saturation hinders the devices' driving ability, which can be eliminated with carefully engineered contact configurations. On the other hand, by introducing the nonlinearity to monolithic analog artificial neural network circuits, the circuits' perception ability can be significantly enhanced, as evidenced using a coronavirus disease 2019 (COVID-19) critical illness prediction model. This work provides a comprehension of the field-effect at the electrical contacts to 2D materials, which is fundamental to the design, simulation, and fabrication of electronics based on 2D materials. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material (results of the simulation and SEM) is available in the online version of this article at 10.1007/s12274-021-3670-y.

Anisotropic Signal Processing with Trigonal Selenium Nanosheet Synaptic Transistors.

Hardware implementation of an artificial neural network requires neuromorphic devices to process information with low energy consumption and high heterogeneity. Here we demonstrate an electrolyte-gated synaptic transistor (EGT) based on a trigonal selenium (t-Se) nanosheet. Due to the intrinsic low conductivity of the Se channel, the t-Se synaptic transistor exhibits ultralow energy consumption, less than 0.1 pJ per spike. More importantly, the intrinsic low symmetry of t-Se offers a strong anisotropy along its c- and a-axis in electrical conductance with a ratio of up to 8.6. The multiterminal EGT device exhibits an anisotropic response of filtering behavior to the same external stimulus, which enables it to mimic the heterogeneous signal transmission process of the axon-multisynapse biostructure in the human brain. The proof-of-concept device in this work represents an important step to develop neuromorphic electronics for processing complex signals.

Preparation of microcapsule antioxidative wall materials of pine nut oil by the Maillard reaction.

BACKGROUND: Maillard reaction products contribute to the amelioration of the biological functions or physical properties of foods and can be used to make dependable antioxidant wall materials for microcapsules of pine nut oil. The present study aimed to analyze the effects of temperature on the Maillard reaction of dry heat processes using gelatin/gum arabic (GE/GA) or gelatin/gum arabic/maltodextrin (GE/GA/MD) models and the products of the Maillard reaction as encapsulants to protect pine nut oil, as well as to evaluate the characteristics of the microcapsules. RESULTS: The grafting degree of the product increased with the temperature increments during the Maillard reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the polysaccharide covalently linked to the protein. The antioxidant capability of the Maillard products at 80 °C was the highest. The 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, lipid peroxidation-inhibiting activity and reducing power of the GE/GA/MD model were higher than those of the GE/GA model. With in vitro digestion of Maillard products, GE/GA/MD pine nut oil microcapsules exhibited greater oil release in artificial gastric and enteric juices. Microencapsulated pine nut oil had more stable oxygen, which protected the oil, compared to unencapsulated pine nut oil. CONCLUSION: Temperature affects the degree of the Maillard reaction on GE/GA and GE/GA/MD models. © 2018 Society of Chemical Industry.

A model for interprofessional health care: lessons learned from craniofacial teams.

Seventy-six years ago, Herbert K. Cooper, DDS, DSc, LHD, FACD, created the first interprofessional health care team in response to the frequency of craniofacial anomalies and related speech and hearing deficits in Lancaster, Pa. His experiences and those from subsequent "medical-dental-nursing-pharmacy allied health professions" craniofacial teams inform and provide "best practices" for the future of interprofessional education. This paper revisits the genesis of craniofacial teams and highlights successes, challenges and cost benefits applicable today.

Molecular characterization of a rice mutator-phenotype derived from an incompatible cross-pollination reveals transgenerational mobilization of multiple transposable elements and extensive epigenetic instability.

BACKGROUND: Inter-specific hybridization occurs frequently in plants, which may induce genetic and epigenetic instabilities in the resultant hybrids, allopolyploids and introgressants. It remains unclear however whether pollination by alien pollens of an incompatible species may impose a "biological stress" even in the absence of genome-merger or genetic introgression, whereby genetic and/or epigenetic instability of the maternal recipient genome might be provoked. RESULTS: We report here the identification of a rice mutator-phenotype from a set of rice plants derived from a crossing experiment involving two remote and apparently incompatible species, Oryza sativa L. and Oenothera biennis L. The mutator-phenotype (named Tong211-LP) showed distinct alteration in several traits, with the most striking being substantially enlarged panicles. Expectably, gel-blotting by total genomic DNA of the pollen-donor showed no evidence for introgression. Characterization of Tong211-LP (S0) and its selfed progenies (S1) ruled out contamination (via seed or pollen) or polyploidy as a cause for its dramatic phenotypic changes, but revealed transgenerational mobilization of several previously characterized transposable elements (TEs), including a MITE (mPing), and three LTR retrotransposons (Osr7, Osr23 and Tos17). AFLP and MSAP fingerprinting revealed extensive, transgenerational alterations in cytosine methylation and to a less extent also genetic variation in Tong211-LP and its immediate progenies. mPing mobility was found to correlate with cytosine methylation alteration detected by MSAP but not with genetic variation detected by AFLP. Assay by q-RT-PCR of the steady-state transcript abundance of a set of genes encoding for the various putative DNA methyltransferases, 5-methylcytosine DNA glycosylases, and small interference RNA (siRNA) pathway-related proteins showed that, relative to the rice parental line, heritable perturbation in expression of 12 out of the 13 genes occurred in the mutator-phenotype and its sefled progenies. CONCLUSION: Transgenerational epigenetic instability in the form of altered cytosine methylation and its associated TE activity occurred in a rice mutator-phenotype produced by pollinating the rice stigma with pollens of O. biennis. Heritably perturbed homeostatic expression-state of genes involved in maintenance of chromatin structure is likely an underlying cause for the alien pollination-induced transgenerational epigenetic/genetic instability, and which occurred apparently without entailing genome merger or genetic introgression.