1,409 research outputs found

    Cooperative Carbon Dioxide Adsorption in Alcoholamine- and Alkoxyalkylamine-Functionalized Metal-Organic Frameworks.

    Get PDF
    A series of structurally diverse alcoholamine- and alkoxyalkylamine-functionalized variants of the metal-organic framework Mg2 (dobpdc) are shown to adsorb CO2 selectively via cooperative chain-forming mechanisms. Solid-state NMR spectra and optimized structures obtained from van der Waals-corrected density functional theory calculations indicate that the adsorption profiles can be attributed to the formation of carbamic acid or ammonium carbamate chains that are stabilized by hydrogen bonding interactions within the framework pores. These findings significantly expand the scope of chemical functionalities that can be utilized to design cooperative CO2 adsorbents, providing further means of optimizing these powerful materials for energy-efficient CO2 separations

    Medication burden in the first 5 years following diagnosis of type 2 diabetes: findings from the ADDITION-UK trial cohort.

    Get PDF
    INTRODUCTION: Individuals with screen-detected diabetes are likely to receive intensified pharmacotherapy to improve glycaemic control and general cardiometabolic health. Individuals are often asymptomatic, and little is known about the degree to which polypharmacy is present both before, and after diagnosis. We aimed to describe and characterize the pharmacotherapy burden of individuals with screen-detected diabetes at diagnosis, 1 and 5 years post-diagnosis. METHODS: The prescription histories of 1026 individuals with screen-detected diabetes enrolled in the ADDITION-UK trial of the promotion of intensive treatment were coded into general medication types at diagnosis, 1 and 5 years post-diagnosis. The association between change in the count of several medication types and age, baseline 10-year UK Prospective Diabetes Study (UKPDS) cardiovascular disease (CVD risk), sex, intensive treatment group and number of medications was explored. RESULTS: Just under half of individuals were on drugs unrelated to cardioprotection before diagnosis (42%), and this increased along with a rise in the number of prescribed diabetes-related and cardioprotective drugs. The medication profile over the first 5 years suggests multimorbidity and polypharmacy is present in individuals with screen-detected diabetes. Higher modeled CVD risk at baseline was associated with a greater increase in cardioprotective and diabetes-related medication, but not an increase in other medications. CONCLUSION: As recommended in national guidelines, our results suggest that treatment of diabetes was influenced by the underlying risk of CVD. While many individuals did not start glucose lowering and cardioprotective therapies in the first 5 years after diagnosis, more information is required to understand whether this represents unmet need, or patient-centered care. TRIAL REGISTRATION NUMBER: CNT00237549.This study was supported by the Welcome Trust (grant number G061895), the Medical Research Council (Grant numbers G0001164 and MC_UU_12015/4) and the National Institute for Health Research (Grant number RP-PG-0606-1259).This is the final version of the article. It first appeared from BMJ via http://dx.doi.org/10.1136/bmjdrc-2014-00007

    Transdermal Blood Sampling for C-peptide Is a Minimally Invasive, Reliable Alternative to Venous Sampling in Children and Adults With Type 1 Diabetes

    Get PDF
    OBJECTIVE:C-peptide and islet autoantibodies are key type 1 diabetes biomarkers, typically requiring venous sampling, which limits their utility. We assessed transdermal capillary blood (TCB) collection as a practical alternative.RESEARCH DESIGN AND METHODS:Ninety-one individuals (71 with type 1 diabetes, 20 controls; individuals with type 1 diabetes: aged median 14.8 years [interquartile range (IQR) 9.1–17.1], diabetes duration 4.0 years [1.5–7.7]; controls: 42.2 years [38.0–52.1]) underwent contemporaneous venous and TCB sampling for measurement of plasma C-peptide. Participants with type 1 diabetes also provided venous serum and plasma, and TCB plasma for measurement of autoantibodies to glutamate decarboxylase, islet antigen-2, and zinc transporter 8. The ability of TCB plasma to detect significant endogenous insulin secretion (venous C-peptide ≥200 pmol/L) was compared along with agreement in levels, using Bland-Altman. Venous serum was compared with venous and TCB plasma for detection of autoantibodies, using established thresholds. Acceptability was assessed by age-appropriate questionnaire.RESULTS:Transdermal sampling took a mean of 2.35 min (SD 1.49). Median sample volume was 50 µL (IQR 40–50) with 3 of 91 (3.3%) failures, and 13 of 88 (14.7%) <35 µL. TCB C-peptide showed good agreement with venous plasma (mean venous ln[C-peptide] – TCB ln[C-peptide] = 0.008, 95% CI [−0.23, 0.29], with 100% [36 of 36] sensitivity/100% [50 of 50] specificity to detect venous C-peptide ≥200 pmol/L). Where venous serum in multiple autoantibody positive TCB plasma agreed in 22 of 32 (sensitivity 69%), comparative specificity was 35 of 36 (97%). TCB was preferred to venous sampling (type 1 diabetes: 63% vs. 7%; 30% undecided).CONCLUSIONS:Transdermal capillary testing for C-peptide is a sensitive, specific, and acceptable alternative to venous sampling; TCB sampling for islet autoantibodies needs further assessment

    Prospective associations between sedentary time, physical activity, fitness and cardiometabolic risk factors in people with type 2 diabetes.

    Get PDF
    AIMS/HYPOTHESIS: The aim of this study was to examine the prospective associations between objectively measured physical activity energy expenditure (PAEE), sedentary time, moderate-to-vigorous-intensity physical activity (MVPA), cardiorespiratory fitness (CRF) and cardiometabolic risk factors over 4 years in individuals with recently diagnosed diabetes. METHODS: Among 308 adults (mean age 61.0 [SD 7.2] years; 34% female) with type 2 diabetes from the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care (ADDITION)-Plus study, we measured physical activity using individually calibrated combined heart rate and movement sensing. Multivariable linear regression models were constructed to examine the associations between baseline PAEE, sedentary time, MVPA, CRF and cardiometabolic risk factors and clustered cardiometabolic risk (CCMR) at follow-up, and change in these exposures and change in CCMR and its components over 4 years of follow-up. RESULTS: Individuals who increased their PAEE between baseline and follow-up had a greater reduction in waist circumference (-2.84 cm, 95% CI -4.84, -0.85) and CCMR (-0.17, 95% CI -0.29, -0.04) compared with those who decreased their PAEE. Compared with individuals who decreased their sedentary time, those who increased their sedentary time had a greater increase in waist circumference (3.20 cm, 95% CI 0.84, 5.56). Increases in MVPA were associated with reductions in systolic blood pressure (-6.30 mmHg, 95% CI -11.58, -1.03), while increases in CRF were associated with reductions in CCMR (-0.23, 95% CI -0.40,-0.05) and waist circumference (-3.79 cm, 95% CI -6.62, -0.96). Baseline measures were generally not predictive of cardiometabolic risk at follow-up. CONCLUSIONS/INTERPRETATION: Encouraging people with recently diagnosed diabetes to increase their physical activity and decrease their sedentary time may have beneficial effects on their waist circumference, blood pressure and CCMR.The trial is supported by the Medical Research Council (grant reference no. G0001164), the Wellcome Trust (grant reference no. G061895), National Health Service R&D support funding (including the Primary Care Research and Diabetes Research Networks) and National Institute of Health Research under its Programme Grants for Applied Research scheme (RP-PG-0606-1259). SJG is a member of the NIHR School for Primary Care Research. The views expressed in this publication are those of the authors and not necessarily those of the National Health Service, the NIHR, or the UK Department of Health. We are grateful to Diabetes UK for providing patient information materials.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00125-015-3756-

    A realist process evaluation of robot-assisted surgery: integration into routine practice and impacts on communication, collaboration and decision-making

    Get PDF
    YesBackground: The implementation of robot-assisted surgery (RAS) can be challenging, with reports of surgical robots being underused. This raises questions about differences compared with open and laparoscopic surgery and how best to integrate RAS into practice. Objectives: To (1) contribute to reporting of the ROLARR (RObotic versus LAparoscopic Resection for Rectal cancer) trial, by investigating how variations in the implementation of RAS and the context impact outcomes; (2) produce guidance on factors likely to facilitate successful implementation; (3) produce guidance on how to ensure effective teamwork; and (4) provide data to inform the development of tools for RAS. Design: Realist process evaluation alongside ROLARR. Phase 1 – a literature review identified theories concerning how RAS becomes embedded into practice and impacts on teamwork and decision-making. These were refined through interviews across nine NHS trusts with theatre teams. Phase 2 – a multisite case study was conducted across four trusts to test the theories. Data were collected using observation, video recording, interviews and questionnaires. Phase 3 – interviews were conducted in other surgical disciplines to assess the generalisability of the findings. Findings: The introduction of RAS is surgeon led but dependent on support at multiple levels. There is significant variation in the training provided to theatre teams. Contextual factors supporting the integration of RAS include the provision of whole-team training, the presence of handpicked dedicated teams and the availability of suitably sized operating theatres. RAS introduces challenges for teamwork that can impact operation duration, but, over time, teams develop strategies to overcome these challenges. Working with an experienced assistant supports teamwork, but experience of the procedure is insufficient for competence in RAS and experienced scrub practitioners are important in supporting inexperienced assistants. RAS can result in reduced distraction and increased concentration for the surgeon when he or she is supported by an experienced assistant or scrub practitioner. Conclusions: Our research suggests a need to pay greater attention to the training and skill mix of the team. To support effective teamwork, our research suggests that it is beneficial for surgeons to (1) encourage the team to communicate actions and concerns; (2) alert the attention of the assistant before issuing a request; and (3) acknowledge the scrub practitioner’s role in supporting inexperienced assistants. It is beneficial for the team to provide oral responses to the surgeon’s requests. Limitations: This study started after the trial, limiting impact on analysis of the trial. The small number of operations observed may mean that less frequent impacts of RAS were missed. Future work: Future research should include (1) exploring the transferability of guidance for effective teamwork to other surgical domains in which technology leads to the physical or perceptual separation of surgeon and team; (2) exploring the benefits and challenges of including realist methods in feasibility and pilot studies; (3) assessing the feasibility of using routine data to understand the impact of RAS on rare end points associated with patient safety; (4) developing and evaluating methods for whole-team training; and (5) evaluating the impact of different physical configurations of the robotic console and team members on teamwork.National Inst for Health Research (NIHR

    Water Enables Efficient CO2 Capture from Natural Gas Flue Emissions in an Oxidation-Resistant Diamine-Appended Metal-Organic Framework.

    Get PDF
    Supported by increasingly available reserves, natural gas is achieving greater adoption as a cleaner-burning alternative to coal in the power sector. As a result, carbon capture and sequestration from natural gas-fired power plants is an attractive strategy to mitigate global anthropogenic CO2 emissions. However, the separation of CO2 from other components in the flue streams of gas-fired power plants is particularly challenging due to the low CO2 partial pressure (∼40 mbar), which necessitates that candidate separation materials bind CO2 strongly at low partial pressures (≤4 mbar) to capture ≥90% of the emitted CO2. High partial pressures of O2 (120 mbar) and water (80 mbar) in these flue streams have also presented significant barriers to the deployment of new technologies for CO2 capture from gas-fired power plants. Here, we demonstrate that functionalization of the metal-organic framework Mg2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) with the cyclic diamine 2-(aminomethyl)piperidine (2-ampd) produces an adsorbent that is capable of ≥90% CO2 capture from a humid natural gas flue emission stream, as confirmed by breakthrough measurements. This material captures CO2 by a cooperative mechanism that enables access to a large CO2 cycling capacity with a small temperature swing (2.4 mmol CO2/g with ΔT = 100 °C). Significantly, multicomponent adsorption experiments, infrared spectroscopy, magic angle spinning solid-state NMR spectroscopy, and van der Waals-corrected density functional theory studies suggest that water enhances CO2 capture in 2-ampd-Mg2(dobpdc) through hydrogen-bonding interactions with the carbamate groups of the ammonium carbamate chains formed upon CO2 adsorption, thereby increasing the thermodynamic driving force for CO2 binding. In light of the exceptional thermal and oxidative stability of 2-ampd-Mg2(dobpdc), its high CO2 adsorption capacity, and its high CO2 capture rate from a simulated natural gas flue emission stream, this material is one of the most promising adsorbents to date for this important separation

    Amine Dynamics in Diamine-Appended Mg2(dobpdc) Metal-Organic Frameworks.

    Get PDF
    Variable-temperature 15N solid-state NMR spectroscopy is used to uncover the dynamics of three diamines appended to the metal-organic framework Mg2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate), an important family of CO2 capture materials. The results imply both bound and free amine nitrogen environments exist when diamines are coordinated to the framework open Mg2+ sites. There are rapid exchanges between two nitrogen environments for all three diamines, the rates and energetics of which are quantified by 15N solid-state NMR data and corroborated by density functional theory calculations and molecular dynamics simulations. The activation energy for the exchange provides a measure of the metal-amine bond strength. The unexpected negative correlation between the metal-amine bond strength and CO2 adsorption step pressure reveals that metal-amine bond strength is not the only important factor in determining the CO2 adsorption properties of diamine-appended Mg2(dobpdc) metal-organic frameworks

    Mosaic Amplification of Multiple Receptor Tyrosine Kinase Genes in Glioblastoma

    Get PDF
    SummaryTumor heterogeneity has been implicated in tumor growth and progression as well as resistance to therapy. We present an example of genetic heterogeneity in human malignant brain tumors in which multiple closely related driver genes are amplified and activated simultaneously in adjacent intermingled cells. We have observed up to three different receptor tyrosine kinases (EGFR, MET, PDGFRA) amplified in single tumors in different cells in a mutually exclusive fashion. Each subpopulation was actively dividing, and the genetic changes resulted in protein production, and coexisting subpopulations shared common early genetic mutations indicating their derivation from a single precursor cell. The stable coexistence of different clones within the same tumor will have important clinical implications for tumor resistance to targeted therapies
    • …
    corecore