T cell-derived interleukin-22 drives the expression of CD155 by cancer cells to suppress NK cell function and promote metastasis.

Although T cells can exert potent anti-tumor immunity, a subset of T helper (Th) cells producing interleukin-22 (IL-22) in breast and lung tumors is linked to dismal patient outcome. Here, we examined the mechanisms whereby these T cells contribute to disease. In murine models of lung and breast cancer, constitutional and T cell-specific deletion of Il22 reduced metastases without affecting primary tumor growth. Deletion of the IL-22 receptor on cancer cells decreases metastasis to a degree similar to that seen in IL-22-deficient mice. IL-22 induced high expression of CD155, which bound to the activating receptor CD226 on NK cells. Excessive activation led to decreased amounts of CD226 and functionally impaired NK cells, which elevated the metastatic burden. IL-22 signaling was also associated with CD155 expression in human datasets and with poor patient outcomes. Taken together, our findings reveal an immunosuppressive circuit activated by T cell-derived IL-22 that promotes lung metastasis.

Tissue resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22.

During metastasis, cancer cells invade, intravasate, enter the circulation, extravasate, and colonize target organs. Here, we examined the role of interleukin (IL)-22 in metastasis. Immune cell-derived IL-22 acts on epithelial tissues, promoting regeneration and healing upon tissue damage, but it is also associated with malignancy. Il22-deficient mice and mice treated with an IL-22 antibody were protected from colon-cancer-derived liver and lung metastasis formation, while overexpression of IL-22 promoted metastasis. Mechanistically, IL-22 acted on endothelial cells, promoting endothelial permeability and cancer cell transmigration via induction of endothelial aminopeptidase N. Multi-parameter flow cytometry and single-cell sequencing of immune cells isolated during cancer cell extravasation into the liver revealed iNKT17 cells as source of IL-22. iNKT-cell-deficient mice exhibited reduced metastases, which was reversed by injection of wild type, but not Il22-deficient, invariant natural killer T (iNKT) cells. IL-22-producing iNKT cells promoting metastasis were tissue resident, as demonstrated by parabiosis. Thus, IL-22 may present a therapeutic target for prevention of metastasis.

Primary data on symptom burden and quality of life among elderly patients at risk of dying during unplanned admissions to an NHS hospital: a cohort study using EuroQoL and the integrated palliative care outcome scale.

BACKGROUND: Older people account heavily for palliative care needs at the population level and are growing in number as the population ages. There is relatively little high-quality data on symptom burden and quality of life, since these data are not routinely collected, and this group are under-recruited in primary research. It is unclear which measurement tools are best suited to capture burdens and experience. METHODS: We recruited a cohort of 221 patients aged 75 + years with poor prognosis who had an unplanned admission via the emergency department in a large urban hospital in England between 2019 and 2020. Risk of dying was assessed using the CriSTAL tool. We collected primary data and combined these with routine health records. Baseline clinical data and patient reported quality of life outcomes were collected on admission and reassessed within the first 72 h of presentation using two established tools: EQ-5D-5 L, EQ-VAS and the Integrated Palliative Outcomes Scale (IPOS). RESULTS: Completion rate was 68% (n = 151) and 33.1% were known to have died during admission or within 6 months post-discharge. The vast majority (84.8%) reported severe difficulties with at least one dimension of EQ-5D-5 L at baseline and improvements in EQ-VAS observed at reassessment in 51.7%. The baseline IPOS revealed 78.2% of patients rating seven or more items as moderate, severe or overwhelming, but a significant reduction (-3.6, p < 0.001) in overall physical symptom severity and prevalence was also apparent. No significant differences were noted in emotional symptoms or changes in communication/practical issues. IPOS total score at follow up was positively associated with age, having comorbidities (Charlson index score > = 1) and negatively associated with baseline IPOS and CriSTAL scores. CONCLUSION: Older people with poor prognosis admitted to hospital have very high symptom burden compared to population norms, though some improvement following assessment was observed on all measures. These data provide valuable descriptive information on quality of life among a priority population in practice and policy and can be used in future research to identify suitable interventions and model their effects.

Do Mini-Mental State Examination and Montreal Cognitive Assessment predict high-cost health care users? A competing risks analysis in The Irish Longitudinal Study on Ageing.

OBJECTIVES: Policymakers want to better identify in advance the 10% of people who account for approximately 75% of health care costs. We evaluated how well Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) predicted high costs in Ireland. METHODS/DESIGN: We used five waves from The Irish Longitudinal Study on Ageing, a biennial population-representative survey of people aged 50+ (2010-2018). We used competing risks analysis where our outcome of interest was "high costs" (top 10% at any wave) and the competing outcome was dying or loss to follow-up without first having the high-cost outcome. Our binary predictors of interest were a 'low score' (bottom 10% in the sample) in MMSE (≤25 pts) and MoCA (≤19 pts) at baseline, and we calculated sub-hazard ratios after controlling for sociodemographic, clinical and functional factors. RESULTS: Of 5856 participants, 1427 (24%) had the 'high cost' outcome; 1463 (25%) had a competing outcome; and 2966 (51%) completed eight years of follow-up without either outcome. In multivariable regressions a low MoCA score was associated with high costs (SHR: 1.38 (95% CI: 1.2-1.6) but a low MMSE score was not. Low MoCA score at baseline had a higher true positive rate (40%) than did low MMSE score (35%). The scores had similar association with exit from the study. CONCLUSIONS: MoCA had superior predictive accuracy for high costs than MMSE but the two scores identify somewhat different types of high-cost user. Combining the approaches may improve efforts to identify in advance high-cost users.

Predicting mortality in The Irish Longitudinal Study on Ageing (TILDA): development of a four-year index and comparison with international measures.

OBJECTIVES: We aimed to replicate existing international (US and UK) mortality indices using Irish data. We developed and validated a four-year mortality index for adults aged 50 + in Ireland and compared performance with these international indices. We then extended this model by including additional predictors (self-report and healthcare utilization) and compared its performance to our replication model. METHODS: Eight thousand one hundred seventy-four participants in The Irish Longitudinal Study on Ageing were split for development (n = 4,121) and validation (n = 4,053). Six baseline predictor categories were examined (67 variables total): demographics; cardiovascular-related illness; non-cardiovascular illness; health and lifestyle variables; functional variables; self-report (wellbeing and social connectedness) and healthcare utilization. We identified variables independently associated with four-year mortality in the development cohort and attached these variables a weight according to strength of association. We summed the weights to calculate a single index score for each participant and evaluated predicted accuracy in the validation cohort. RESULTS: Our final 14-predictor (extended) model assigned risk points for: male (1pt); age (65-69: 2pts; 70-74: 4 pts; 75-79: 4pts; 80-84: 6pts; 85 + : 7pts); heart attack (1pt); cancer (3pts); smoked past age 30 (2pts); difficulty walking 100 m (2pts); difficulty using the toilet (3pts); difficulty lifting 10lbs (1pts); poor self-reported health (1pt); and hospital admission in previous year (1pt). Index discrimination was strong (ROC area = 0.78). DISCUSSION: Our index is predictive of four-year mortality in community-dwelling older Irish adults. Comparisons with the international indices show that our 12-predictor (replication) model performed well and suggests that generalisability is high. Our 14-predictor (extended) model showed modest improvements compared to the 12-predictor model.

Mortality risk associated with combinations of loneliness and social isolation. Findings from The Irish Longitudinal Study on Ageing (TILDA).

BACKGROUND: Social distancing and similar measures in response to the coronavirus disease 2019 pandemic have greatly increased loneliness and social isolation among older adults. Understanding the association between loneliness and mortality is therefore critically important. We examined whether combinations of loneliness and social isolation, using a metric named social asymmetry, was associated with increased mortality risk. METHODS: The sample was derived from participants in The Irish Longitudinal Study on Ageing, a nationally representative sample of community-dwelling older adults aged ≥50. Survey data were linked to official death registration records. Cox proportional hazards regressions and competing risk survival analyses were used to examine the association between social asymmetry and all-cause and cause-specific mortality. RESULTS: Of four social asymmetry groups, concordant low lonely (low loneliness, low isolation) included 35.5% of participants; 26.4% were concordant high lonely (high loneliness, high isolation); 19.2% were discordant robust (low loneliness, high isolation) and 18.9% discordant susceptible (high loneliness, low isolation). The concordant high lonely (hazard ratio [HR] = 1.43, 95% confidence interval [CI]: 1.09-1.87) and discordant robust (HR = 1.37, 95% CI: 1.04-1.81) groups had an increased mortality risk compared to those in the concordant low lonely group. The concordant high lonely group had an increased risk of mortality due to diseases of the circulatory system (sub-distribution hazard ratio = 1.52, 95% CI: 1.03-2.25). CONCLUSION: We found that social asymmetry predicted mortality over a 7-year follow-up period. Our results confirm that a mismatch between subjective loneliness and objective social isolation, as well as the combination of loneliness and social isolation, were associated with an increased all-cause mortality risk.

Proportion of deaths in hospital in European countries: trends and associations from panel data (2005-2017).

BACKGROUND: End-of-life care attracts major policy interest. Place of death is an important metric of individual experience and health system performance. Most people prefer to die at home, but hospital is the most common place of death in high-income countries. Little is known about international trends in place of death over time. METHODS: We aimed to collate population-level data on place of death in Europe from 2005 to 2017, and to evaluate association with national characteristics and policy choices. We sought data on hospital as the place of death from the 32 European Economic Area countries. We identified national economic, societal, demographic and health system predictors from Eurostat, OECD and the WHO. We analyzed these cross-national panel data using linear regression with panel-corrected standard errors. RESULTS: Our analytic dataset included 30 countries accounting for over 95% of Europe's population. Average national proportion of deaths occurring in hospital in the study period ranged from 26% to 68%, with a median of 52%. Trends vary markedly by region and wealth, with low and decreasing rate in the North-West, and high and increasing prevalence in the South and East. Controlling for demographic and economic factors, strong palliative care provision and generous government finance of long-term care were associated with fewer hospital deaths. CONCLUSIONS: We found modifiable policy choices associated with hospital mortality, as well as wider structural economic and societal factors. Policymakers can act to reduce the proportion of dying in hospital.

The association between varying levels of palliative care involvement on costs during terminal hospitalizations in Canada from 2012 to 2015.

BACKGROUND: Inpatient palliative care is associated with lower inpatient costs; however, this has yet to be studied using a more nuanced, multi-tiered measure of inpatient palliative care and a national population-representative dataset. Using a population-based cohort of Canadians who died in hospital, our objectives were to: describe patients' receipt of palliative care and active interventions in their terminal hospitalization; and examine the relationship between inpatient palliative care and hospitalization costs. METHODS: Retrospective cohort study using data from the Discharge Abstract Database in Canada between fiscal years 2012 and 2015. The cohort were Canadian adults (age ≥ 18 years) who died in hospital between April 1st, 2012 and March 31st, 2015 (N = 250,640). The exposure was level of palliative care involvement defined as: medium-high, low, or no palliative care. The main measure was acute care costs calculated using resource intensity weights multiplied by the cost of standard hospital stay, represented in 2014 Canadian dollars (CAD). Descriptive statistics were represented as median (IQR), and n(%). We modelled cost as a function of palliative care using a gamma generalized estimating equation (GEE) model, accounting for clustering by hospital. RESULTS: There were 250,640 adults who died in hospital. Mean age was 76 (SD 14), 47% were female. The most common comorbidities were: metastatic cancer (21%), heart failure (21%), and chronic obstructive pulmonary disease (16%). Of the decedents, 95,450 (38%) had no palliative care involvement, 98,849 (38%) received low involvement, and 60,341 (24%) received medium to high involvement. Controlling for age, sex, province and predicted hospital mortality risk at admission, the cost per day of a terminal hospitalization was: $1359 (95% CI 1323: 1397) (no involvement), $1175 (95% CI 1146: 1206) (low involvement), and $744 (95% CI 728: 760) (medium-high involvement). CONCLUSIONS: Increased involvement of palliative care was associated with lower costs. Future research should explore whether this relationship holds for non-terminal hospitalizations, and whether palliative care in other settings impacts inpatient costs.

Effectiveness of a nurse-delivered (FOCUS+) and a web-based (iFOCUS) psychoeducational intervention for people with advanced cancer and their family caregivers (DIAdIC): study protocol for an international randomized controlled trial.

BACKGROUND: Worldwide, millions of people with advanced cancer and their family caregivers are experiencing physical and psychological distress. Psychosocial support and education can reduce distress and prevent avoidable healthcare resource use. To date, we lack knowledge from large-scale studies on which interventions generate positive outcomes for people with cancer and their informal caregivers' quality of life. This protocol describes the DIAdIC study that will evaluate the effectiveness of two psychosocial and educational interventions aimed at improving patient-family caregiver dyads' emotional functioning and self-efficacy. METHODS: We will conduct an international multicenter three-arm randomized controlled trial in Belgium, Denmark, Ireland, Italy, The Netherlands, and the United Kingdom. In each country, 156 dyads (936 in total) of people with advanced cancer and their family caregiver will be randomized to one of the study arms: 1) a nurse-led face-to-face intervention (FOCUS+), 2) a web-based intervention (iFOCUS) or 3) a control group (care as usual). The two interventions offer tailored psychoeducational support for patient-family caregiver dyads. The nurse-led face-to-face intervention consists of two home visits and one online video session and the web-based intervention is completed independently by the patient-family caregiver dyad in four online sessions. The interventions are based on the FOCUS intervention, developed in the USA, that addresses five core components: family involvement, optimistic outlook, coping effectiveness, uncertainty reduction, and symptom management. The FOCUS intervention will be adapted to the European context. The primary outcomes are emotional functioning and self-efficacy of the patient and the family caregiver, respectively. The secondary outcomes are quality of life, benefits of illness, coping, dyadic communication, and ways of giving support of the patient and family caregiver. DISCUSSION: DIAdIC aims to develop cost-effective interventions that integrate principles of early palliative care into standard care. The cross-country setup in six European countries allows for comparison of effectiveness of the interventions in different healthcare systems across Europe. By focusing on empowerment of the person with cancer and their family caregiver, the results of this RCT can contribute to the search for cost-effective novel interventions that can relieve constraints on professional healthcare. TRIAL REGISTRATION: Registration on ClinicalTrials.gov on 12/11/2020, identifier NCT04626349 . DATE AND VERSION IDENTIFIER: 20211209_DIAdIC_Protocol_Article.

End-of-life experience for older adults in Ireland: results from the Irish longitudinal study on ageing (TILDA).

BACKGROUND: End-of-life experience is a subject of significant policy interest. National longitudinal studies offer valuable opportunities to examine individual-level experiences. Ireland is an international leader in palliative and end-of-life care rankings. We aimed to describe the prevalence of modifiable problems (pain, falls, depression) in Ireland, and to evaluate associations with place of death, healthcare utilisation, and formal and informal costs in the last year of life. METHODS: The Irish Longitudinal Study on Ageing (TILDA) is a nationally representative sample of over-50-year-olds, recruited in Wave 1 (2009-2010) and participating in biannual assessment. In the event of a participant's death, TILDA approaches a close relative or friend to complete a voluntary interview on end-of-life experience. We evaluated associations using multinomial logistic regression for place of death, ordinary least squares for utilisation, and generalised linear models for costs. We identified 14 independent variables for regressions from a rich set of potential predictors. Of 516 confirmed deaths between Waves 1 and 3, the analytic sample contained 375 (73%) decedents for whom proxies completed an interview. RESULTS: There was high prevalence of modifiable problems pain (50%), depression (45%) and falls (41%). Those with a cancer diagnosis were more likely to die at home (relative risk ratio: 2.5; 95% CI: 1.3-4.8) or in an inpatient hospice (10.2; 2.7-39.2) than those without. Place of death and patterns of health care use were determined not only by clinical need, but other factors including age and household structure. Unpaid care accounted for 37% of all care received but access to this care, as well as place of death, may be adversely affected by living alone or in a rural area. Deficits in unpaid care are not balanced by higher formal care use. CONCLUSIONS: Despite Ireland's well-established palliative care services, clinical need is not the sole determinant of end-of-life experience. Cancer diagnosis and access to family supports were additional key determinants. Future policy reforms should revisit persistent inequities by diagnosis, which may be mitigated through comprehensive geriatric assessment in hospitals. Further consideration of policies to support unpaid carers is also warranted.

Cancer cells induce interleukin-22 production from memory CD4+ T cells via interleukin-1 to promote tumor growth.

IL-22 has been identified as a cancer-promoting cytokine that is secreted by infiltrating immune cells in several cancer models. We hypothesized that IL-22 regulation would occur at the interface between cancer cells and immune cells. Breast and lung cancer cells of murine and human origin induced IL-22 production from memory CD4+ T cells. In the present study, we found that IL-22 production in humans is dependent on activation of the NLRP3 inflammasome with the subsequent release of IL-1ß from both myeloid and T cells. IL-1 receptor signaling via the transcription factors AhR and RORγt in T cells was necessary and sufficient for IL-22 production. In these settings, IL-1 induced IL-22 production from a mixed T helper cell population comprised of Th1, Th17, and Th22 cells, which was abrogated by the addition of anakinra. We confirmed these findings in vitro and in vivo in two murine tumor models, in primary human breast and lung cancer cells, and in deposited expression data. Relevant to ongoing clinical trials in breast cancer, we demonstrate here that the IL-1 receptor antagonist anakinra abrogates IL-22 production and reduces tumor growth in a murine breast cancer model. Thus, we describe here a previously unrecognized mechanism by which cancer cells induce IL-22 production from memory CD4+ T cells via activation of the NLRP3 inflammasome and the release of IL-1ß to promote tumor growth. These findings may provide the basis for therapeutic interventions that affect IL-22 production by targeting IL-1 activity.

Assembly, translocation, and activation of XerCD-dif recombination by FtsK translocase analyzed in real-time by FRET and two-color tethered fluorophore motion.

The FtsK dsDNA translocase functions in bacterial chromosome unlinking by activating XerCD-dif recombination in the replication terminus region. To analyze FtsK assembly and translocation, and the subsequent activation of XerCD-dif recombination, we extended the tethered fluorophore motion technique, using two spectrally distinct fluorophores to monitor two effective lengths along the same tethered DNA molecule. We observed that FtsK assembled stepwise on DNA into a single hexamer, and began translocation rapidly (∼ 0.25 s). Without extruding DNA loops, single FtsK hexamers approached XerCD-dif and resided there for ∼ 0.5 s irrespective of whether XerCD-dif was synapsed or unsynapsed. FtsK then dissociated, rather than reversing. Infrequently, FtsK activated XerCD-dif recombination when it encountered a preformed synaptic complex, and dissociated before the completion of recombination, consistent with each FtsK-XerCD-dif encounter activating only one round of recombination.

Effects of deep tillage and municipal green waste compost amendments on soil properties and tree growth in compacted urban soils.

Large trees are often seen as a means of offsetting negative consequences of growing urban densification. To increase the tree canopy cover of dense urban landscapes, developers, planners and urban tree managers are often forced to plant into damaged and compacted sites. Compacted urban soils can hinder the establishment and growth of deep rooted, woody plants by: 1) impeding root exploration and development which is critical for water and nutrient acquisition; 2) reducing infiltration of water into the soil and the availability of water to plants; and 3) reducing gas exchange and the balance between anaerobic and aerobic conditions. At three sites in Melbourne, Australia with compacted and damaged soils, we established four soil remediation treatments: 1 & 2) tillage to 0.25 m with and without 50% (v/v) municipal green waste compost (MGWC) additions, and 3 & 4) tillage to 0.5 m with and without 50% MGWC addition, plus a non-remediated control. Each treatment was replicated (n = 3), and one Corymbia maculata (spotted gum) tree was planted into the centre of each 2 × 2 m treatment plot (n = 15), at all three sites (n = 45). Bulk density and field-saturated hydraulic conductivity were improved by tillage, at least in the short-term. The use of MGWC may maintain these changes for longer. Depending on site soil conditions tree growth may be improved by tillage alone. At one site, we found that additions of MGWC lead to nitrogen immobilisation due to site soil conditions. At another site, deep tillage (with or without MGWC) led to significantly improved tree growth. Compacted and degraded urban soils may be improved through simple tillage and/or organic amendment strategies for the successful establishment of deep rooted woody plants. However, site soil conditions will dictate whether the addition of MGWC is beneficial or not, as one site showed no positive response to any tillage or MGWC. This research has examined a technique that can be used by landscape managers to improve soil physical characteristics and, in certain circumstances, can improve deep-rooted woody plant establishment and growth in challenging compacted urban soil conditions.

Cost analysis of a prospective multi-site cohort study of palliative care consultation teams for adults with advanced cancer: Where do cost-savings come from?

BACKGROUND: Studies report cost-savings from hospital-based palliative care consultation teams compared to usual care only, but drivers of observed differences are unclear. AIM: To analyse cost-differences associated with palliative care consultation teams using two research questions: (Q1) What is the association between early palliative care consultation team intervention, and intensity of services and length of stay, compared to usual care only? (Q2) What is the association between early palliative care consultation team intervention and day-to-day hospital costs, compared to a later intervention? DESIGN: Prospective multi-site cohort study (2007-2011). Patients who received a consultation were placed in the intervention group, those who did not in the comparison group. Intervention group was stratified by timing, and groups were matched using propensity scores. SETTING/PARTICIPANTS: Adults admitted to three US hospitals with advanced cancer. Principle analytic sample contains 863 patients ( nUC = 637; nPC EARLY = 177; nPC LATE = 49) discharged alive. RESULTS: Cost-savings from early palliative care accrue due to both reduced length of stay and reduced intensity of treatment, with an estimated 63% of savings associated with shorter length of stay. A reduction in day-to-day costs is observable in the days immediately following initial consult but does not persist indefinitely. A comparison of early and late palliative care consultation team cost-effects shows negligible difference once the intervention is administered. CONCLUSION: Reduced length of stay is the biggest driver of cost-saving from early consultation for patients with advanced cancer. Patient- and family-centred discussions on goals of care and transition planning initiated by palliative care consultation teams may be at least as important in driving cost-savings as the reduction of unnecessary tests and pharmaceuticals identified by previous studies.

Conformational transitions during FtsK translocase activation of individual XerCD-dif recombination complexes.

Three single-molecule techniques have been used simultaneously and in tandem to track the formation in vitro of single XerCD-dif recombination complexes. We observed the arrival of the FtsK translocase at individual preformed synaptic complexes and demonstrated the conformational change that occurs during their activation. We then followed the reaction intermediate transitions as Holliday junctions formed through catalysis by XerD, isomerized, and were converted by XerC to reaction products, which then dissociated. These observations, along with the calculated intermediate lifetimes, inform the reaction mechanism, which plays a key role in chromosome unlinking in most bacteria with circular chromosomes.

Street Orientation and Side of the Street Greatly Influence the Microclimatic Benefits Street Trees Can Provide in Summer.

Maintaining human thermal comfort (HTC) is essential for pedestrians because people outside can be more susceptible to heat stress and heat stroke. Modification of street microclimates using tree canopy cover can provide important benefits to pedestrians, but how beneficial and under what circumstances is not clear. On sunny summer days, microclimatic measures were made in residential streets with low and high percentages of tree canopy cover in Melbourne, Australia. Streets with east-west (E-W) and streets with north-south (N-S) orientation were repeatedly measured for air temperature, relative humidity, wind speed, solar radiation, and mean radiant temperature on both sides of the street between early morning and midafternoon. Physiological equivalent temperature was estimated to indicate HTC throughout the day. In streets with high-percentage canopy cover, air temperature, relative humidity, solar radiation, and mean radiant temperature were significantly lower than in streets with low-percentage canopy cover. The reductions in air temperature under high-percentage canopy cover were greater for E-W streets (2.1°C) than for N-S streets (0.9°C). For N-S streets, air temperature, mean radiant temperature, and solar radiation were greater on the east pavement in the early morning and greatest on the west pavement in the midafternoon. The midday thermal benefits are restricted to E-W streets, which are oriented in the same direction as the summer sun's zenith. High-percentage canopy cover reduced wind speeds but not enough to offset the other microclimate benefits. These findings can assist urban planners in designing street tree landscapes for optimal HTC in summer, especially in areas of high pedestrian density.

Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids.

To progress from the laboratory to commercial applications, it will be necessary to develop industrially scalable methods to produce large quantities of defect-free graphene. Here we show that high-shear mixing of graphite in suitable stabilizing liquids results in large-scale exfoliation to give dispersions of graphene nanosheets. X-ray photoelectron spectroscopy and Raman spectroscopy show the exfoliated flakes to be unoxidized and free of basal-plane defects. We have developed a simple model that shows exfoliation to occur once the local shear rate exceeds 10(4) s(-1). By fully characterizing the scaling behaviour of the graphene production rate, we show that exfoliation can be achieved in liquid volumes from hundreds of millilitres up to hundreds of litres and beyond. The graphene produced by this method performs well in applications from composites to conductive coatings. This method can be applied to exfoliate BN, MoS2 and a range of other layered crystals.

Tethered fluorophore motion: studying large DNA conformational changes by single-fluorophore imaging.

We have previously introduced tethered fluorophore motion (TFM), a single-molecule fluorescence technique that monitors the effective length of a biopolymer such as DNA. TFM uses the same principles as tethered particle motion (TPM) but employs a single fluorophore in place of the bead, allowing TFM to be combined with existing fluorescence techniques on a standard fluorescence microscope. TFM has been previously been used to reveal the mechanism of two site-specific recombinase systems, Cre-loxP and XerCD-dif. In this work, we characterize TFM, focusing on the theoretical basis and potential applications of the technique. Since TFM is limited in observation time and photon count by photobleaching, we present a description of the sources of noise in TFM. Comparing this with Monte Carlo simulations and experimental data, we show that length changes of 100 bp of double-stranded DNA are readily distinguishable using TFM, making it comparable with TPM. We also show that the commonly recommended pixel size for single-molecule fluorescence approximately optimizes signal to noise for TFM experiments, thus enabling facile combination of TFM with other fluorescence techniques, such as Förster resonance energy transfer (FRET). Finally, we apply TFM to determine the polymerization rate of the Klenow fragment of DNA polymerase I, and we demonstrate its combination with FRET to observe synapsis formation by Cre using excitation by a single laser. We hope that TFM will be a useful addition to the single-molecule toolkit, providing excellent insight into protein-nucleic acid interactions.