1,012 research outputs found

    Exploring cation distribution in ion-exchanged Al,Ga-containing metal-organic frameworks using 17O NMR spectroscopy

    Get PDF
    The authors would like to thank the ERC (Advanced Grant 787073 ADOR) for support. The UK High-Field Solid-State NMR Facility used in this research was funded by EPSRC and BBSRC (EP/T015063/1), in addition to (for results at 850 MHz) he University of Warwick including via part funding through Birmingham Science City Advanced Materials Projects 1 and 2 supported by Advantage West Midlands (AWM) and the European Regional Development Fund (ERDF), and for the 1 GHz instrument, (EP/R029946/1). Collaborative assistance from the Facility Manager Team (Dr Trent Franks, University of Warwick) is acknowledged. The Jeol JSM-IT200 SEM used in this research was supported by the EPSRC Light Element Analysis Facility Grant (EP/T019298/1) and the EPSRC Strategic Equipment Resource Grant (EP/R023751/1). Collaborative assistance from Dr David Miller (University of St Andrews) is acknowledged.A mixed-metal metal–organic framework, (Al,Ga)-MIL-53, synthesised by post-synthetic ion exchange has been investigated using solid-state nuclear magnetic resonance (NMR) spectroscopy, microscopy and energy dispersive X-ray (EDX) spectroscopy. 17O enrichment during the ion-exchange process enables site specific information on the metal distribution to be obtained. Within this work two ion-exchange processes have been explored. In the first approach (exchange of metals in the framework with dissolved metal salts), 17O NMR spectroscopy reveals the formation of crystallites with a core–shell structure, where the cation exchange takes place on the surface of these materials forming a shell with a roughly equal ratio of Al3+ and Ga3+. For the second approach (exchange of metals between two frameworks), no core–shell structure is observed, and instead crystallites containing a majority of Al3+ are obtained with lower levels of Ga3+. Noticeably, these particles show little variation in the metal cation distribution between crystallites, a result not previously observed for bulk (Al,Ga)-MIL-53 materials. In all cases where ion exchange has taken place NMR spectroscopy reveals a slight preference for clustering of like cations.Publisher PDFPeer reviewe

    Computational NMR investigation of mixed-metal (Al,Sc)-MIL-53 and its phase transitions

    Get PDF
    Funding: The authors would like to thank the ERC (Advanced Grant 787073 ADOR) and the Allan Handsel Postgraduate Research Scholarship for Chemistry for studentship funding for ZHD and EALB, respectively. We also acknowledge support from the Collaborative Computational Project on NMR Crystallography (CCP-NC) funded by EPSRC (EP/T026642/1) and from the UK Materials and Molecular Modelling Hub (Young), which is partially funded by EPSRC (EP/T022213/1, EP/W032260/1 and EP/P020194/1) for which access was obtained via the UKCP consortium and funded by EPSRC (EP/P022561/1).Compositionally complex metal-organic frameworks (MOFs) have properties that depend on local structure that is often difficult to characterise. In this paper a density functional theory (DFT) computational study of mixed-metal (Al,Sc)-MIL-53, a flexible MOF with several different forms, was used to calculate the relative energetics of these forms and to predict NMR parameters that can be used to evaluate whether solid-state NMR spectroscopy can be used to differentiate, identify and characterise the forms adopted by mixed-metal MOFs of different composition. The NMR parameters can also be correlated with structural features in the different forms, giving fundamental insight into the nature and origin of the interactions that affect nuclear spins. Given the complexity of advanced NMR experiments required, and the potential need for expensive and difficult isotopic enrichment, the computational work is invaluable in predicting which experiments and approaches are likely to give the most information on the disorder, local structure and pore forms of these mixed-metal MOFs.Publisher PDFPeer reviewe

    Shared decision making in patients with low risk chest pain: prospective randomized pragmatic trial.

    Get PDF
    OBJECTIVE: To compare the effectiveness of shared decision making with usual care in choice of admission for observation and further cardiac testing or for referral for outpatient evaluation in patients with possible acute coronary syndrome. DESIGN: Multicenter pragmatic parallel randomized controlled trial. SETTING: Six emergency departments in the United States. PARTICIPANTS: 898 adults (aged \u3e17 years) with a primary complaint of chest pain who were being considered for admission to an observation unit for cardiac testing (451 were allocated to the decision aid and 447 to usual care), and 361 emergency clinicians (emergency physicians, nurse practitioners, and physician assistants) caring for patients with chest pain. INTERVENTIONS: Patients were randomly assigned (1:1) by an electronic, web based system to shared decision making facilitated by a decision aid or to usual care. The primary outcome, selected by patient and caregiver advisers, was patient knowledge of their risk for acute coronary syndrome and options for care; secondary outcomes were involvement in the decision to be admitted, proportion of patients admitted for cardiac testing, and the 30 day rate of major adverse cardiac events. RESULTS: Compared with the usual care arm, patients in the decision aid arm had greater knowledge of their risk for acute coronary syndrome and options for care (questions correct: decision aid, 4.2 v usual care, 3.6; mean difference 0.66, 95% confidence interval 0.46 to 0.86), were more involved in the decision (observing patient involvement scores: decision aid, 18.3 v usual care, 7.9; 10.3, 9.1 to 11.5), and less frequently decided with their clinician to be admitted for cardiac testing (decision aid, 37% v usual care, 52%; absolute difference 15%; P CONCLUSIONS: Use of a decision aid in patients at low risk for acute coronary syndrome increased patient knowledge about their risk, increased engagement, and safely decreased the rate of admission to an observation unit for cardiac testing.Trial registration ClinicalTrials.gov NCT01969240

    Following the unusual breathing behaviour of 17O-enriched mixed-metal (Al,Ga)-MIL-53 using NMR crystallography

    Get PDF
    The authors would like to thank the ERC (EU FP7 Consolidator Grant 614290 EXONMR and Advanced Grant 787073 ADOR), and EPSRC (EP/N509759/1) for a studentship for CMR. SEA would like to thank the Royal Society and Wolfson Foundation for a merit award. We acknowledge support from the Collaborative Computational Project on NMR Crystallography (CCP-NC) funded by EPSRC (EP/M022501/1) and the UKCP consortium funded by EPSRC (EP/K013564/1). For computational resources we are grateful to the UK Materials and Molecular Modelling Hub, which is partially funded by EPSRC (EP/P020194/1) and the UK HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202). The research data (and/or materials) supporting this publication can be accessed at DOI: https://doi.org/10.17630/31529c8b-f197-484c-929b-ef993a5bea68.69The breathing behaviour of 17O-enriched (Al,Ga)-MIL-53, a terephthalate-based metal organic framework, has been investigated using a combination of solid-state nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction (PXRD) and first-principles calculations. These reveal that the behaviour observed for as-made, calcined, hydrated and subsequently dehydrated mixed-metal MIL-53 materials differs with composition, but cannot be described as the compositionally weighted average of the breathing behaviour seen for the two end members. Although the form of MIL-53 adopted by the as-made material is independent of metal composition, upon calcination, materials with higher levels of Al adopt an open pore (OP) form, as found for the Al end member, but substitution of Ga results in mixed pore materials, with OP and narrow pore (NP) forms co-existing. Although the Ga end member is prone to decomposition under the calcination conditions used, a low level of Al in the starting synthesis (5%) leads to an OP mixed-metal MOF that is stable to calcination. Upon hydration all materials almost exclusively adopt a closed pore (CP) structure, with strong hydrogen bonding interactions with water leading to two distinct resonances from the carboxylate oxygens in 17O NMR spectra. When dehydrated, different framework structures are found for the two end members, OP for Al- MIL-53 and NP for Ga-MIL-53, with the proportion of NP MOF seen to increase systematically with the Ga content in mixed-metal materials, in contrast to the forms seen upon initial calcination. 17O NMR spectra of mixed-metal MIL-53 materials show an increased preference for clustering of like cations as the Ga content increases. This is not a result of the small-scale dry gel conversion reactions used for enrichment, as a similar cation distribution and clustering is also observed for (Al0.5,Ga0.5)-MIL-53 synthesised hydrothermally and enriched with 17O via post-synthetic steaming.Publisher PDFPeer reviewe

    Wastewater surveillance beyond COVID-19: a ranking system for communicable disease testing in the tri-county Detroit area, Michigan, USA

    Get PDF
    IntroductionThroughout the coronavirus disease 2019 (COVID-19) pandemic, wastewater surveillance has been utilized to monitor the disease in the United States through routine national, statewide, and regional monitoring projects. A significant canon of evidence was produced showing that wastewater surveillance is a credible and effective tool for disease monitoring. Hence, the application of wastewater surveillance can extend beyond monitoring SARS-CoV-2 to encompass a diverse range of emerging diseases. This article proposed a ranking system for prioritizing reportable communicable diseases (CDs) in the Tri-County Detroit Area (TCDA), Michigan, for future wastewater surveillance applications at the Great Lakes Water Authority's Water Reclamation Plant (GLWA's WRP).MethodsThe comprehensive CD wastewater surveillance ranking system (CDWSRank) was developed based on 6 binary and 6 quantitative parameters. The final ranking scores of CDs were computed by summing the multiplication products of weighting factors for each parameter, and then were sorted based on decreasing priority. Disease incidence data from 2014 to 2021 were collected for the TCDA. Disease incidence trends in the TCDA were endowed with higher weights, prioritizing the TCDA over the state of Michigan.ResultsDisparities in incidences of CDs were identified between the TCDA and state of Michigan, indicating epidemiological differences. Among 96 ranked CDs, some top ranked CDs did not present relatively high incidences but were prioritized, suggesting that such CDs require significant attention by wastewater surveillance practitioners, despite their relatively low incidences in the geographic area of interest. Appropriate wastewater sample concentration methods are summarized for the application of wastewater surveillance as per viral, bacterial, parasitic, and fungal pathogens.DiscussionThe CDWSRank system is one of the first of its kind to provide an empirical approach to prioritize CDs for wastewater surveillance, specifically in geographies served by centralized wastewater collection in the area of interest. The CDWSRank system provides a methodological tool and critical information that can help public health officials and policymakers allocate resources. It can be used to prioritize disease surveillance efforts and ensure that public health interventions are targeted at the most potentially urgent threats. The CDWSRank system can be easily adopted to geographical locations beyond the TCDA

    Amyotrophic lateral sclerosis–specific quality of life–short form (ALSSQOL‐SF): A brief, reliable, and valid version of the ALSSQOL‐R

    Full text link
    Introduction: The Amyotrophic Lateral Sclerosis (ALS)‐Specific Quality of Life instrument and its revised version (ALSSQOL and ALSSQOL‐R) have strong psychometric properties, and have demonstrated research and clinical utility. In this study we aimed to develop a short form (ALSSQOL‐SF) suitable for limited clinic time and patient stamina. Methods: The ALSSQOL‐SF was created using Item Response Theory and confirmatory factor analysis on 389 patients. A cross‐validation sample of 162 patients assessed convergent, divergent, and construct validity of the ALSSQOL‐SF compared with psychosocial and physical functioning measures. Results: The ALSSQOL‐SF consisted of 20 items. Compared with the ALSSQOL‐R, optimal precision was retained, and completion time was reduced from 15–25 minutes to 2–4 minutes. Psychometric properties for the ALSSQOL‐SF and its subscales were strong. Discussion: The ALSSQOL‐SF is a disease‐specific global QOL instrument that has a short administration time suitable for clinical use, and can provide clinically useful, valid information about persons with ALS. Muscle Nerve 58: 646–654, 2018Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146574/1/mus26203_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146574/2/mus26203.pd

    Prognostic value of Ishak fibrosis stage: Findings from the hepatitis C antiviral long-term treatment against cirrhosis trial

    Full text link
    Studies of the prognostic value of Ishak fibrosis stage are lacking. We used multi-year follow-up of the Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT-C) Trial to determine whether individual Ishak fibrosis stages predicted clinical outcomes in patients with chronic hepatitis C. Baseline liver biopsy specimens from 1050 patients with compensated chronic hepatitis C who had failed combination peginterferon and ribavirin were reviewed by a panel of expert hepatopathologists. Fibrosis was staged with the Ishak scale (ranging from 0 = no fibrosis to 6 = cirrhosis). Biopsy fragmentation and length as well as number of portal tracts were recorded. We compared rates of prespecified clinical outcomes of hepatic decompensation and hepatocellular carcinoma across individual Ishak fibrosis stages. Of 1050 biopsy specimens, 25% were fragmented, 63% longer than 1.5 cm, 69% larger than 10 mm 2 , and 75% had 10 or more portal tracts. Baseline laboratory markers of liver disease severity were worse and the frequency of esophageal varices higher with increasing Ishak stage ( P < 0.0001). The 6-year cumulative incidence of first clinical outcome was 5.6% for stage 2, 16.1% for stage 3, 19.3% for stage 4, 37.8% for stage 5, and 49.3% for stage 6. Among nonfragmented biopsy specimens, the predictive ability of Ishak staging was enhanced; however, no association was observed between Ishak stage and outcomes for fragmented biopsy specimens because of high rates of outcomes for patients with noncirrhotic stages. Similar results were observed with liver transplantation or liver-related death as the outcome. Conclusion : Ishak fibrosis stage predicts clinical outcomes, need for liver transplantation, and liver-related death in patients with chronic hepatitis C. Patients with fragmented biopsy specimens with low Ishak stage may be understaged histologically. (H EPATOLOGY 2010;51:585–594.)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64929/1/23315_ftp.pd

    Variability in the analysis of a single neuroimaging dataset by many teams

    Get PDF
    Data analysis workflows in many scientific domains have become increasingly complex and flexible. To assess the impact of this flexibility on functional magnetic resonance imaging (fMRI) results, the same dataset was independently analyzed by 70 teams, testing nine ex-ante hypotheses1. The flexibility of analytic approaches is exemplified by the fact that no two teams chose identical workflows to analyze the data. This flexibility resulted in sizeable variation in hypothesis test results, even for teams whose statistical maps were highly correlated at intermediate stages of their analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Importantly, a meta-analytic approach that aggregated information across teams yielded significant consensus in activated regions across teams. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2-5. Our findings show that analytic flexibility can have substantial effects on scientific conclusions, and demonstrate factors possibly related to variability in fMRI. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for multiple analyses of the same data. Potential approaches to mitigate issues related to analytical variability are discussed

    Outpatient Opioid Prescriptions are Associated with Future Substance use Disorders and Overdose Following Adolescent Trauma

    Get PDF
    Objective: This study aims to determine if outpatient opioid prescriptions are associated with future substance use disorder (SUD) diagnoses and overdose in injured adolescents five years following hospital discharge. Summary Background Data: Approximately, 1 in 8 adolescents are diagnosed with an SUD and 1 in 10 experience an overdose in the five years following injury. State laws have become more restrictive on opioid prescribing by acute care providers for treating pain, however, prescriptions from other outpatient providers are still often obtained. Methods: This was a retrospective cohort study of patients ages 12–18 admitted to two level I trauma centers. Demographic and clinical data contained in trauma registries were linked to a regional database containing five years of electronic health records and prescription data. Regression models assessed whether number of outpatient opioid prescription fills after discharge at different time points in recovery were associated with a new SUD diagnosis or overdose, while controlling for demographic and injury characteristics, as well as depression and PTSD diagnoses. Results: We linked 669 patients (90.9%) from trauma registries to a regional health information exchange database. Each prescription opioid refill in the first 3 months after discharge increased the likelihood of new SUD diagnoses by 55% (OR:1.55, CI:1.04–2.32). Odds of overdose increased with ongoing opioid use over 2–4 years post-discharge (p = 0.016–0.025). Conclusions: Short-term outpatient opioid prescribing over the first few months of recovery had the largest effect on developing an SUD, while long-term prescription use over multiple years was associated with a future overdose
    corecore