Tandem catalysis by ultrathin metal–organic nanosheets formed through post-synthetic functionalisation of a layered framework

Covalent post-synthetic functionalisation of layered metal–organic frameworks is demonstrated as a new approach to forming ultrathin nanosheets for use in catalysis. An aminoterephthalate framework was partially functionalised with sulfonate chains and exfoliated to form predominantly monolayer nanosheets able to catalyse a two-step acid–base reaction in one pot

Overheating in Scotland: contributing factors in occupied homes

There is growing awareness of the overheating risks in new-build properties in the UK. However, this tends to be considered a problem principally for the southern regions in the UK, only becoming a serious issue in the north of England in the medium-term and in the long-term for Scotland. This notion tends to be largely predicated upon climate change predictions, differences in latitude and summer air temperatures. This paper describes the results from Building Performance Evaluation (BPE) studies over a two-year period from 26 occupied new-build homes across Scotland which demonstrated incidences of overheating. Results suggest that low-energy buildings are susceptible to overheating despite northerly latitudes, with 54% of houses studied overheating for more than six months annually, and 27% of homes overheating for less than 10% of the year. Evidence indicated that commonly used prediction tools do not appear to anticipate overheating adequately. This paper maps common overheating causes due to design and the role of occupants, identifying the risks due to the regulatory system, prediction and procurement processes, and design and construction. A common finding was that design and occupancy factors appear to have a greater impact on overheating more than location and climatic factors

The oblique plane deformity in slipped capital femoral epiphysis.

Background Slipped capital femoral epiphysis (SCFE) is commonly treated with in situ pinning. However, a severe slip may not be suitable for in situ pinning because the required screw trajectory is such that it risks perforating the posterior cortex and damaging the remaining blood supply to the capital epiphysis. In such cases, an anteriorly placed screw may also cause impingement. It is also possible to underestimate the severity of the slip using conventional radiographs. The aim of this study was to describe and evaluate a novel method for calculating the true deformity in SCFE and to assess the interobserver and intraobserver reliability of this technique. Methods We selected 20 patients with varying severity of SCFE who presented to our institution. Cross-sectional imaging [either axial computed tomography (CT) scans or magnetic resonance imaging (MRI) scans] and anteroposterior (AP) pelvis radiographs were assessed by four reviewers with varying levels of experience on two occasions. The degree of slip on the axial image and on the AP pelvis radiographs were measured and, from this, the oblique plane deformity was calculated using the method as popularised by Paley. The intraclass correlation coefficient (ICC) was calculated to determine the interobserver and intraobserver reliabilities between and amongst the raters. Results The interobserver reliability for the calculated oblique plane deformity in SCFE ICC was 0.947 [95 % confidence interval (CI) 0.90–0.98] and the intraobserver reliability for the calculated oblique plane deformity of individual raters ranged from 0.81 to 0.94. The deformity in the oblique plane was always greater than the deformity measured in the axial or the coronal plane alone. Conclusion This method for calculating the true deformity in SCFE has excellent interobserver and intraobserver reliability and can be used to guide treatment options. This technique is a reliable and reproducible method for assessing the degree of deformity in SCFE. It may help orthopaedic surgeons with varying degrees of experience to identify which hips are suitable for in situ pinning and those which require surgical dislocation and anatomical reduction, given that plain radiographs in a single plane will underestimate the true deformity in the oblique plane. Level of evidence Level II diagnostic study

Absolute Calibration of a 200 MeV Proton Polarimeter for Use with the Brookhaven Linac

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

Differentially Addressable Cavities within Metal-Organic Cage-Cross-Linked Polymeric Hydrogels

Here we report a new class of hydrogels formed by polymers that are cross-linked through subcomponent self-assembled metal–organic cages. Selective encapsulation of guest molecules within the cages creates two distinct internal phases within the hydrogel, which allows for contrasting release profiles of related molecules depending on their aptitude for encapsulation within the cages. The hydrogels were fabricated into microparticles via a droplet-based microfluidic approach and proved responsive to a variety of stimuli, including acid and competing amine or aldehyde subcomponents, allowing for the triggered release of cargo

Increasing alkyl chain length in a series of layered metal–organic frameworks aids ultrasonic exfoliation to form nanosheets

Metal–organic framework nanosheets (MONs) are attracting increasing attention as a diverse class of two-dimensional materials derived from metal–organic frameworks (MOFs). The principles behind the design of layered MOFs that can readily be exfoliated to form nanosheets, however, remain poorly understood. Here we systematically investigate an isoreticular series of layered MOFs functionalized with alkoxy substituents in order to understand the effect of substituent alkyl chain length on the structure and properties of the resulting nanosheets. A series of 2,5-alkoxybenzene-1,4-dicarboxylate ligands (O2CC6H2(OR)2CO2, R = methyl–pentyl, 1–5, respectively) was used to synthesize copper paddle-wheel MOFs. Rietveld and Pawley fitting of powder diffraction patterns for compounds Cu(3–5)(DMF) showed they adopt an isoreticular series with two-dimensional connectivity in which the interlayer distance increases from 8.68 Å (R = propyl) to 10.03 Å (R = pentyl). Adsorption of CO2 by the MOFs was found to increase from 27.2 to 40.2 cm3 g–1 with increasing chain length, which we attribute to the increasing accessible volume associated with increasing unit-cell volume. Ultrasound was used to exfoliate the layered MOFs to form MONs, with shorter alkyl chains resulting in higher concentrations of exfoliated material in suspension. The average height of MONs was investigated by AFM and found to decrease from 35 ± 26 to 20 ± 12 nm with increasing chain length, with the thinnest MONs observed being only 5 nm, corresponding to five framework layers. These results indicate that careful choice of ligand functionalities can be used to tune nanosheet structure and properties, enabling optimization for a variety of applications

Anthropogenic Space Weather

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

Metal‐organic framework nanosheets: programmable 2D materials for catalysis, sensing, electronics, and separation applications

Metal-organic framework nanosheets (MONs) have recently emerged as a distinct class of 2D materials with programmable structures that make them useful in diverse applications. In this review, the breadth of applications that have so far been investigated are surveyed, thanks to the distinct combination of properties afforded by MONs. How: 1) The high surface areas and readily accessible active sites of MONs mean they have been exploited for a variety of heterogeneous, photo-, and electro-catalytic applications; 2) their diverse surface chemistry and wide range of optical and electronic responses have been harnessed for the sensing of small molecules, biological molecules, and ions; 3) MONs tunable optoelectronic properties and nanoscopic dimensions have enabled them to be harnessed in light harvesting and emission, energy storage, and other electronic devices; 4) the anisotropic structure and porous nature of MONs mean they have shown great promise in a variety of gas separation and water purification applications; are discussed. The aim is to draw links between the uses of MONs in these different applications in order to highlight the common opportunities and challenges presented by this promising class of nanomaterials

Fluctuating Nematic Elastomer Membranes: a New Universality Class

We study the flat phase of nematic elastomer membranes with rotational symmetry spontaneously broken by in-plane nematic order. Such state is characterized by a vanishing elastic modulus for simple shear and soft transverse phonons. At harmonic level, in-plane orientational (nematic) order is stable to thermal fluctuations, that lead to short-range in-plane translational (phonon) correlations. To treat thermal fluctuations and relevant elastic nonlinearities, we introduce two generalizations of two-dimensional membranes in a three dimensional space to arbitrary D-dimensional membranes embedded in a d-dimensional space, and analyze their anomalous elasticities in an expansion about D=4. We find a new stable fixed point, that controls long-scale properties of nematic elastomer membranes. It is characterized by singular in-plane elastic moduli that vanish as a power-law eta_lambda=4-D of a relevant inverse length scale (e.g., wavevector) and a finite bending rigidity. Our predictions are asymptotically exact near 4 dimensions.Comment: 18 pages, 4 eps figures. submitted to PR

Targeted nasal vaccination provides antibody-independent protection against Staphylococcus aureus.

Despite showing promise in preclinical models, anti-Staphylococcus aureus vaccines have failed in clinical trials. To date, approaches have focused on neutralizing/opsonizing antibodies; however, vaccines exclusively inducing cellular immunity have not been studied to formally test whether a cellular-only response can protect against infection. We demonstrate that nasal vaccination with targeted nanoparticles loaded with Staphylococcus aureus antigen protects against acute systemic S. aureus infection in the absence of any antigen-specific antibodies. These findings can help inform future developments in staphylococcal vaccine development and studies into the requirements for protective immunity against S. aureus