Imprinted Networks as Chiral Pumps

We investigate the interaction between a chirally imprinted network and a solvent of chiral molecules. We find, a liquid crystalline polymer network is preferentially swollen by one component of a racemic solvent. This ability to separate is linked to the chiral order parameter of the network, and can be reversibly controlled via temperature or a mechanical deformation. It is maximal near the point at which the network loses its imprinted structure. One possible practical application of this effect would be a mechanical device for sorting mixed chiral molecules.Comment: 4 pages, 5 figure

Ground-based remote sensing of an elevated forest fire aerosol layer at Whistler, BC: implications for interpretation of mountaintop chemistry

On 30 August 2009, intense forest fires in interior British Columbia (BC) coupled with winds from the east and northeast resulted in transport of a broad forest fire plume across southwestern BC. The physico-chemical and optical characteristics of the plume as observed from Saturna Island (AERONET), CORALNet-UBC and the Whistler Mountain air chemistry facility were consistent with forest fire plumes that have been observed elsewhere in continental North America. However, the importance of three-dimensional transport in relation to the interpretation of mountaintop chemistry observations is highlighted on the basis of deployment of both a <i>CL31</i> ceilometer and a single particle mass spectrometer (SPMS) in a mountainous setting. The SPMS is used to identify the biomass plume based on levoglucosan and potassium markers. Data from the SPMS are also used to show that the biomass plume was correlated with nitrate, but not correlated with sulphate or sodium. This study not only provides baseline measurements of biomass burning plume physico-chemical characteristics in western Canada, but also highlights the importance of lidar remote sensing methods in the interpretation of mountaintop chemistry measurements

Forming reproducible non-lithographic nanocontacts to assess the effect of contact compressive strain in nanomaterials

The application of electrical nanoprobes to measure and characterize nanomaterials has become widely spread. However, the formation of quality electrical contacts using metallic probes on nanostructures has not been directly assessed. We investigate here the electrical behaviour of non-lithographically formed contacts to ZnO nanowires (NWs) and develop a method to reproducibly form Ohmic contacts for accurate electrical measurement of the nanostructures. The contacting method used in this work relies on an electrical feedback mechanism to determine the point of contact to the individual NWs, ensuring minimal compressive strain at the contact. This developed method is compared with the standard tip deflection contacting technique and shows a significant improvement in reproducibility. The effect of excessive compressive strain at the contact was investigated, with a change from rectifying to ohmic I–V behaviour observed as compressive strain at the contact was increased, leading to irreversible changes to the electrical properties of the NW. This work provides an ideal method for forming reproducible non-lithographic nanocontacts to a multitude of nanomaterials

Visible Light Communication Using a Blue GaN μLED and Fluorescent Polymer Color Converter

This letter presents a novel technique to achieve high-speed visible light communication (VLC) using white light generated by a blue GaN mu LED and a yellow fluorescent copolymer. We generated white light suitable for room illumination by optimizing the ratio between the blue electroluminescence of the mu LED and yellow photoluminescence of the copolymer color converter. Taking advantage of the components' high bandwidth, we demonstrated 1.68 Gb/s at a distance of 3 cm (at 240 lx illumination). To the best of our knowledge, this is the fastest white light VLC results using a single blue LED/color converter combination.PostprintPeer reviewe

Optimal combinable and dedicated energy crop scenarios for marginal land

Modern biomass energy sources account for less than 2% of primary world energy supplies while major economies have enabled legislation that aims to increase bioenergy production. In response to controversies over first generation biofuel, it has been argued that ‘marginal land’ should be used to produce dedicated energy crops (DECs). However, defining marginality of agricultural land is complex, and moreover, DECs would have to out-compete current agricultural production in these areas. Utilising a bio-economic farm-level modelling approach we investigate the impact that crop yield penalties resulting from production in marginal land contexts have on financially optimal farm-level crop plans. Where farm businesses choose to de-invest in own farm machinery, yield reductions of less than 10% for winter wheat result in a financially optimal switch to 100% miscanthus production. By contrast, in the presence of own farm machinery, winter wheat yield penalties of 30% are required before 100% miscanthus production is financially optimal. However, under circumstances where DECs also suffer yield penalties on marginal land, the financially optimal crop mix includes combinable crops. The results demonstrate that the optimal crop mix is dependent upon the relative combinable and DEC yields, together with farm-level decisions towards machinery ownership. The focus of much policy attention relating to production of DECs on ‘marginal land’ is therefore argued to be incomplete. Policies which encourage farmers to de-invest in own farm machinery, or incentivise the purchase of specific DEC machinery, may play an important role in assisting the development of DEC production

The incidence of myocardial injury following post-operative Goal Directed Therapy.

BACKGROUND: Studies suggest that Goal Directed Therapy (GDT) results in improved outcome following major surgery. However, there is concern that pre-emptive use of inotropic therapy may lead to an increased incidence of myocardial ischaemia and infarction. METHODS: Post hoc analysis of data collected prospectively during a randomised controlled trial of the effects of post-operative GDT in high-risk general surgical patients. Serum troponin T concentrations were measured at baseline and on day 1 and day 2 following surgery. Continuous ECG monitoring was performed during the eight hour intervention period. Patients were followed up for predefined cardiac complications. A univariate analysis was performed to identify any associations between potential risk factors for myocardial injury and elevated troponin T concentrations. RESULTS: GDT was associated with fewer complications, and a reduced duration of hospital stay. Troponin T concentrations above 0.01 microg l-1 were identified in eight patients in the GDT group and six in the control group. Values increased above 0.05 microg l-1 in four patients in the GDT group and two patients in the control group. There were no overall differences in the incidence of elevated troponin T concentrations. The incidence of cardiovascular complications was also similar. None of the patients, in whom troponin T concentrations were elevated, developed ECG changes indicating myocardial ischaemia during the intervention period. The only factor to be associated with elevated troponin T concentrations following surgery was end-stage renal failure. CONCLUSION: The use of post-operative GDT does not result in an increased incidence of myocardial injury

Trends, patterns and psychological influences on COVID-19 vaccination intention: Findings from a large prospective community cohort study in England and Wales (Virus Watch)

Background: Vaccination intention is key to the success of any vaccination programme, alongside vaccine availability and access. Public intention to take a COVID-19 vaccine is high in England and Wales compared to other countries, but vaccination rate disparities between ethnic, social and age groups has led to concern. Methods: Online survey of prospective household community cohort study participants across England and Wales (Virus Watch). Vaccination intention was measured by individual participant responses to ‘Would you accept a COVID-19 vaccine if offered?’, collected in December 2020 and February 2021. Responses to a 13-item questionnaire collected in January 2021 were analysed using factor analysis to investigate psychological influences on vaccination intention. // Results: Survey response rate was 56% (20,785/36,998) in December 2020 and 53% (20,590/38,727) in February 2021, with 14,880 adults reporting across both time points. In December 2020, 1,469 (10%) participants responded ‘No’ or ‘Unsure’. Of these people, 1,266 (86%) changed their mind and responded ‘Yes’ or ‘Already had a COVID-19 vaccine’ by February 2021. Vaccination intention increased across all ethnic groups and levels of social deprivation. Age was most strongly associated with vaccination intention, with 16–24-year-olds more likely to respond “Unsure” or “No” versus “Yes” than 65–74-year-olds in December 2020 (OR: 4.63, 95 %CI: 3.42, 6.27 & OR 7.17 95 %CI: 4.26, 12.07 respectively) and February 2021 (OR: 27.92 95 %CI: 13.79, 56.51 & OR 17.16 95 %CI: 4.12, 71.55). The association between ethnicity and vaccination intention weakened, but did not disappear, over time. Both vaccine- and illness-related psychological factors were shown to influence vaccination intention. // Conclusions: Four in five adults (86%) who were reluctant or intending to refuse a COVID-19 vaccine in December 2020 had changed their mind in February 2021 and planned to accept, or had already accepted, a vaccine

Leaching as a pretreatment process to complement torrefaction in improving co-firing characteristics of Jatropha curcas seed cake

The presence of certain inorganic elements in biomass causes issues such as slagging, fouling and corrosion when co-firing with coal for power generation. In this work, the efficacy of leaching to remove these elements from Jatropha curcas seed cake was investigated. Leaching of both untorrefied and torrefied seed cakes was carried out in Milli-Q water at temperatures of 20, 35 and 50 °C. At 20 °C, the two critical elements, potassium and chlorine, decreased by as much as 85 and 97 %, respectively. Leaching at higher temperatures was only beneficial for the more intensely torrefied biomass, since they were more resistant to leaching. The electrical conductivity and ion content of the leachates were measured, as were the inorganic elemental content, dry ash content, volatile matter content and higher heating value (HHV) of the solid seed cake. A secondary benefit of the leaching was an increase in the HHV by up to 10 %

Nanomechanical detection of antibiotic-mucopeptide binding in a model for superbug drug resistance

The alarming growth of the antibiotic-resistant superbugs methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) is driving the development of new technologies to investigate antibiotics and their modes of action. We report the label-free detection of vancomycin binding to bacterial cell wall precursor analogues (mucopeptides) on cantilever arrays, with 10 nM sensitivity and at clinically relevant concentrations in blood serum. Differential measurements quantified binding constants for vancomycin-sensitive and vancomycin-resistant mucopeptide analogues. Moreover, by systematically modifying the mucopeptide density we gain new insights into the origin of surface stress. We propose that stress is a product of a local chemical binding factor and a geometrical factor describing the mechanical connectivity of regions affected by local binding in terms of a percolation process. Our findings place BioMEMS devices in a new class of percolative systems. The percolation concept will underpin the design of devices and coatings to significantly lower the drug detection limit and may also impact on our understanding of antibiotic drug action in bacteria.Comment: Comments: This paper consists of the main article (6 pages, 5 figures) plus Supplemental Material (6 pages, 3 figures). More details are available at http://www.london-nano.co

Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B.1.1.7 lineage in London, UK: a whole-genome sequencing and hospital-based cohort study

BACKGROUND: Emergence of variants with specific mutations in key epitopes in the spike protein of SARS-CoV-2 raises concerns pertinent to mass vaccination campaigns and use of monoclonal antibodies. We aimed to describe the emergence of the B.1.1.7 variant of concern (VOC), including virological characteristics and clinical severity in contemporaneous patients with and without the variant. METHODS: In this cohort study, samples positive for SARS-CoV-2 on PCR that were collected from Nov 9, 2020, for patients acutely admitted to one of two hospitals on or before Dec 20, 2020, in London, UK, were sequenced and analysed for the presence of VOC-defining mutations. We fitted Poisson regression models to investigate the association between B.1.1.7 infection and severe disease (defined as point 6 or higher on the WHO ordinal scale within 14 days of symptoms or positive test) and death within 28 days of a positive test and did supplementary genomic analyses in a cohort of chronically shedding patients and in a cohort of remdesivir-treated patients. Viral load was compared by proxy, using PCR cycle threshold values and sequencing read depths. FINDINGS: Of 496 patients with samples positive for SARS-CoV-2 on PCR and who met inclusion criteria, 341 had samples that could be sequenced. 198 (58%) of 341 had B.1.1.7 infection and 143 (42%) had non-B.1.1.7 infection. We found no evidence of an association between severe disease and death and lineage (B.1.1.7 vs non-B.1.1.7) in unadjusted analyses (prevalence ratio [PR] 0·97 [95% CI 0·72-1·31]), or in analyses adjusted for hospital, sex, age, comorbidities, and ethnicity (adjusted PR 1·02 [0·76-1·38]). We detected no B.1.1.7 VOC-defining mutations in 123 chronically shedding immunocompromised patients or in 32 remdesivir-treated patients. Viral load by proxy was higher in B.1.1.7 samples than in non-B.1.1.7 samples, as measured by cycle threshold value (mean 28·8 [SD 4·7] vs 32·0 [4·8]; p=0·0085) and genomic read depth (1280 [1004] vs 831 [682]; p=0·0011). INTERPRETATION: Emerging evidence exists of increased transmissibility of B.1.1.7, and we found increased virus load by proxy for B.1.1.7 in our data. We did not identify an association of the variant with severe disease in this hospitalised cohort. FUNDING: University College London Hospitals NHS Trust, University College London/University College London Hospitals NIHR Biomedical Research Centre, Engineering and Physical Sciences Research Council