Single-channel EOG sleep staging on a heterogeneous cohort of subjects with sleep disorders.

Sleep staging based on full polysomnography is the gold standard in the diagnosis of many sleep disorders. It is however costly, complex, and obtrusive due to the use of multiple electrodes. Automatic sleep staging based on single-channel electro-oculography (EOG) is a promising alternative, requiring fewer electrodes which could be self-applied below the hairline.

Studying sleep: towards the identification of hypnogram features that drive expert interpretation.

Study Objectives: Hypnograms contain a wealth of information and play an important role in sleep medicine. However, interpretation of the hypnogram is a difficult task and requires domain knowledge and "clinical intuition." This study aimed to uncover which features of the hypnogram drive interpretation by physicians.

Modeling the Impact of Inter-Rater Disagreement on Sleep Statistics Using Deep Generative Learning.

Sleep staging is the process by which an overnight polysomnographic measurement is segmented into epochs of 30 seconds, each of which is annotated as belonging to one of five discrete sleep stages. The resulting scoring is graphically depicted as a hypnogram, and several overnight sleep statistics are derived, such as total sleep time and sleep onset latency. Gold standard sleep staging as performed by human technicians is time-consuming, costly, and comes with imperfect inter-scorer agreement, which also results in inter-scorer disagreement about the overnight statistics.

Representations of temporal sleep dynamics: Review and synthesis of the literature.

Sleep is characterized by an intricate variation of brain activity over time. Measuring these temporal sleep dynamics is relevant for elucidating healthy and pathological sleep mechanisms. The rapidly increasing possibilities for obtaining and processing sleep registrations have led to an abundance of data, which can be challenging to analyze and interpret.

Controlling the Bioreceptor Spatial Distribution at the Nanoscale for Single Molecule Counting in Microwell Arrays.

The ability to detect low concentrations of protein biomarkers is crucial for the early-stage detection of many diseases and therefore indispensable for improving diagnostic devices for healthcare. Here, we demonstrate that by integrating DNA nanotechnologies like DNA origami and aptamers, we can design innovative biosensing concepts for reproducible and sensitive detection of specific targets. DNA origami structures decorated with aptamers were studied as a novel tool to structure the biosensor surface with nanoscale precision in a digital detection bioassay, enabling control of the density, orientation, and accessibility of the bioreceptor to optimize the interaction between target and aptamer.

Graphite and Graphene Fairy Circles: A Bottom-Up Approach for the Formation of Nanocorrals.

A convenient covalent functionalization approach and nanopatterning method of graphite and graphene is developed. In contrast to expectations, electrochemically activated dediazotization of a mixture of two aryl diazonium compounds in aqueous media leads to a spatially inhomogeneous functionalization of graphitic surfaces, creating covalently modified surfaces with quasi-uniform spaced islands of pristine graphite or graphene, coined nanocorrals. Cyclic voltammetry and chronoamperometry approaches are compared.

Intrinsic Properties of Single Graphene Nanoribbons in Solution: Synthetic and Spectroscopic Studies.

We report a novel type of structurally defined graphene nanoribbons (GNRs) with uniform width of 1.7 nm and average length up to 58 nm. These GNRs are decorated with pending Diels-Alder cycloadducts of anthracenyl units and N- n-hexadecyl maleimide.

Self-Assembled Polystyrene Beads for Templated Covalent Functionalization of Graphitic Substrates Using Diazonium Chemistry.

A network of self-assembled polystyrene beads was employed as a lithographic mask during covalent functionalization reactions on graphitic surfaces to create nanocorrals for confined molecular self-assembly studies. The beads were initially assembled into hexagonal arrays at the air-liquid interface and then transferred to the substrate surface. Subsequent electrochemical grafting reactions involving aryl diazonium molecules created covalently bound molecular units that were localized in the void space between the nanospheres.

Thermodynamic Study of the Interaction of Bovine Serum Albumin and Amino Acids with Cellulose Nanocrystals.

The interaction of bovine serum albumin (BSA) with sulfated, carboxylated, and pyridinium-grafted cellulose nanocrystals (CNCs) was studied as a function of the degree of substitution by determining the adsorption isotherm and by directly measuring the thermodynamics of interaction. The adsorption of BSA onto positively charged pyridinium-grafted cellulose nanocrystals followed Langmuirian adsorption with the maximum amount of adsorbed protein increasing linearly with increasing degree of substitution. The binding mechanism between the positively charged pyridinum-grafted cellulose nanocrystals and BSA was found to be endothermic and based on charge neutralization.

Area-selective passivation of sp carbon surfaces by supramolecular self-assembly.

Altering the chemical reactivity of graphene can offer new opportunities for various applications. Here, we report that monolayers of densely packed n-pentacontane significantly reduce the covalent grafting of aryl radicals to graphitic surfaces. The effect is highly local in nature and on fully covered substrates grafting can occur only at monolayer imperfections such as interdomain borders and vacancy defects.

Poly(ethylene oxide) Functionalized Graphene Nanoribbons with Excellent Solution Processability.

Structurally well-defined graphene nanoribbons (GNRs) have attracted great interest as next-generation semiconductor materials. The functionalization of GNRs with polymeric side chains, which can widely broaden GNR-related studies on physiochemical properties and potential applications, has remained unexplored. Here, we demonstrate the bottom-up solution synthesis of defect-free GNRs grafted with flexible poly(ethylene oxide) (PEO) chains.

Chemical vapour deposition of zeolitic imidazolate framework thin films.

Integrating metal-organic frameworks (MOFs) in microelectronics has disruptive potential because of the unique properties of these microporous crystalline materials. Suitable film deposition methods are crucial to leverage MOFs in this field. Conventional solvent-based procedures, typically adapted from powder preparation routes, are incompatible with nanofabrication because of corrosion and contamination risks.

Covalent modification of graphene and graphite using diazonium chemistry: tunable grafting and nanomanipulation.

We shine light on the covalent modification of graphite and graphene substrates using diazonium chemistry under ambient conditions. We report on the nature of the chemical modification of these graphitic substrates, the relation between molecular structure and film morphology, and the impact of the covalent modification on the properties of the substrates, as revealed by local microscopy and spectroscopy techniques and electrochemistry. By careful selection of the reagents and optimizing reaction conditions, a high density of covalently grafted molecules is obtained, a result that is demonstrated in an unprecedented way by scanning tunneling microscopy (STM) under ambient conditions.

On the stability of surface-confined nanoporous molecular networks.

Self-assembly of molecular building blocks into two-dimensional nanoporous networks has been a topic of broad interest for many years. However, various factors govern the specific outcome of the self-assembly process, and understanding and controlling these are key to successful creation. In this work, the self-assembly of two alkylated dehydrobenzo[12]annulene building blocks was compared at the liquid-solid interface.