Tailored Permeation Through ≈1 nm Thick Carbon Nanomembranes by Subtle Changes in Their Molecular Design.

Due to their nanoscale thickness (≈1 nm) and exceptional selectivity for permeation of gases, nanomembranes made of 2D materials possess high potential for energy-efficient nanofiltration applications. In this respect, organic carbon nanomembranes (CNMs), synthesized via electron irradiation-induced crosslinking of aromatic self-assembled monolayers (SAMs), are particularly attractive, as their structure can be flexibly tuned by choice of molecular precursors. However, tailored permeation of CNMs, defined by their molecular design, has not been yet demonstrated. In this work, it is shown that the permeation of helium (He), deuterium (D2) and heavy water (D2O) for CNMs synthesized from biphenyl-based SAMs on silver (C6H5-C6H4-(CH2)n-COO/Ag, n = 2-6) can be tuned by orders of magnitude by changing the structure of the molecular precursors by just a single methylene unit. The selectivity in permeation of D2O/D2 with an unprecedented value of 200 000 can be achieved in this way. The temperature-dependent study reveals a clear correlation between the molecular design and the permeation mechanisms facilitating therewith tailored synthesis of molecular 2D materials for separation technologies.

Gas Transport Mechanisms through Molecular Thin Carbon Nanomembranes.

Molecular thin carbon nanomembranes (CNMs) synthesized by electron irradiation induced cross-linking of aromatic self-assembled monolayers (SAMs) are promising 2D materials for the next generation of filtration technologies. Their unique properties including ultimately low thickness of ≈1 nm, sub-nanometer porosity, mechanical and chemical stability are attractive for the development of innovative filters with low energy consumption, improved selectivity, and robustness. However, the permeation mechanisms through CNMs resulting in, e.g., an ≈1000 times higher fluxes of water in comparison to helium have not been yet understood. Here, a study of the permeation of He, Ne, D2 , CO2 , Ar, O2 and D2 O using mass spectrometry in the temperature range from room temperature to ≈120 °C is studied. As a model system, CNMs made from [1″,4',1',1]-terphenyl-4-thiol SAMs are investigated. It is found out that all studied gases experience an activation energy barrier upon the permeation which scales with their kinetic diameters. Moreover, their permeation rates are dependent on the adsorption on the nanomembrane surface. These findings enable to rationalize the permeation mechanisms and establish a model, which paves the way toward the rational design not only of CNMs but also of other organic and inorganic 2D materials for energy-efficient and highly selective filtration applications.

Improving care for patients with dementia hospitalized for acute somatic illness in a specialized care unit: a feasibility study.

BACKGROUND: Persons with dementia hospitalized for an acute illness have a high risk of poor outcomes and add to the burden on acute care systems. We developed a segregated Special Care Unit (SCU) in a somatic hospital for patients with challenging behavior resulting from dementia and/or delirium. This pilot study evaluates the feasibility and patient outcomes. METHODS: The SCU was established with environmental features that allow for safe and unrestricted ambulation within the unit and create a home-like atmosphere. Daytime activities structure the day and assure additional professional presence. The staff received intensive specialized training. Feasibility criteria were: acceptance by the staff, avoidance of transfers to geriatric psychiatry, lack of serious falls and mortality. Patient outcome criteria were ADL (Barthel index), mobility scores and behavior scores (Wilcoxon's, McNemar tests, pre-post design). RESULTS: 332 consecutively admitted patients were enrolled. The SCU has been well received by the staff. Length of hospital stay did not differ from other hospital patients (15.3 +/- 8.3 vs. 15.0 +/- 10.3 days, p = 0.54). Six patients were transferred to geriatric psychiatry. Two patients suffered a fall-related hip fracture. The median Barthel Index improved significantly (admission 30, discharge 45, p < 0.001), with only 8.5% of patients suffering functional loss. Wandering, aggression and agitation were significantly reduced (p < 0.001). CONCLUSIONS: The SCU has improved the care of patients with challenging behavior. Decline in ADL function and institutionalization occurred to a lesser degree than would be expected in this group of patients. Despite the selection of patients with behavioral problems, transfer to psychiatry was rare.

A special care unit for acutely ill patients with dementia and challenging behaviour as a model of geriatric care.

This paper describes the development and management of a new model of care for hospitalized patients with challenging behaviour evoked by dementia and/or delirium. To ameliorate care for patients with dementia in a geriatric acute care hospital a segregated Special Care Unit for patients with challenging behaviour was created. Environmental features allow for safe and unrestricted ambulation within the unit and create a home-like atmosphere. Day-time activities structure the day and assure additional professional presence in the unit. An intensive training program for the staff was provided. The SCU has been well accepted by the staff and is considered to be an improvement in care. Psychological burden of the nurses did not increase over a time period of one year in caring for these difficult patients.