1,579 research outputs found

    Covalent organic frameworks as multifunctional materials for chemical detection

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    Sensitive and selective detection of chemical and biological analytes is critical in various scientific and technological fields. As an emerging class of multifunctional materials, covalent organic frameworks (COFs) with their unique properties of chemical modularity, large surface area, high stability, low density, and tunable pore sizes and functionalities, which together define their programmable properties, show promise in advancing chemical detection. This review demonstrates the recent progress in chemical detection where COFs constitute an integral component of the achieved function. This review highlights how the unique properties of COFs can be harnessed to develop different types of chemical detection systems based on the principles of chromism, luminescence, electrical transduction, chromatography, spectrometry, and others to achieve highly sensitive and selective detection of various analytes, ranging from gases, volatiles, ions, to biomolecules. The key parameters of detection performance for target analytes are summarized, compared, and analyzed from the perspective of the detection mechanism and structure–property–performance correlations of COFs. Conclusions summarize the current accomplishments and analyze the challenges and limitations that exist for chemical detection under different mechanisms. Perspectives on how future directions of research can advance the COF-based chemical detection through innovation in novel COF design and synthesis, progress in device fabrication, and exploration of novel modes of detection are also discussed

    A GPU-Based Approach for Real-Time Haptic Rendering of 3D Fluids

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    Real-time haptic rendering of three-dimensional fluid flow will improve the interactivity and realism of video games and surgical simulators, but it remains a challenging undertaking due to its high computational cost. In this work we propose an innovative GPUbased approach that enables real-time haptic rendering of highresolution 3D Navier-Stokes fluids. We show that moving the vast majority of the computation to the GPU allows for the simulation of touchable fluids at resolutions and frame rates that are significantly higher than any other recent real-time methods without a need for pre-computations [Baxter and Lin 2004; Mora and Lee 2008; Dobashi et al. 2006]

    Bimetallic Two-Dimensional Metal–Organic Frameworks for the Chemiresistive Detection of Carbon Monoxide

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    This paper describes the demonstration of a series of heterobimetallic, isoreticular 2D conductive metal–organic frameworks (MOFs) with metallophthalocyanine (MPc, M=Co and Ni) units interconnected by Cu nodes towards low-power chemiresistive sensing of ppm levels of carbon monoxide (CO). Devices achieve a sub-part-per-million (ppm) limit of detection (LOD) of 0.53 ppm toward CO at a low driving voltage of 0.1 V. MPc-based Cu-linked MOFs can continuously detect CO at 50 ppm, the permissible exposure limit required by the Occupational Safety and Health Administration (OSHA), for multiple exposures, and realize CO detection in air and in humid environment. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), density functional theory (DFT) calculations, and comparison experiments suggest the contribution of Cu nodes to CO binding and the essential role of MPc units in tuning and amplifying the sensing response

    Disparities in Use of Human Epidermal Growth Hormone Receptor 2–Targeted Therapy for Early-Stage Breast Cancer

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    Trastuzumab is a key component of adjuvant therapy for stage I to III human epidermal growth factor receptor 2 (HER2)–positive breast cancer. The rates and patterns of trastuzumab use have never been described in a population-based sample. The recent addition of HER2 information to the SEER-Medicare database offers an opportunity to examine patterns of trastuzumab use and to evaluate possible disparities in receipt of trastuzumab

    Unraveling the Electrical and Magnetic Properties of Layered Conductive Metal-Organic Framework With Atomic Precision

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    This paper describes structural elucidation of a layered conductive metal-organic framework (MOF) material Cu3(C6O6)2 by microcrystal electron diffraction with sub-angstrom precision. This insight enables the first identification of an unusual π-stacking interaction in a layered MOF material characterized by an extremely short (2.73 Å) close packing of the ligand arising from pancake bonding and ordered water clusters within pores. Band structure analysis suggests semiconductive properties of the MOF, which are likely related to the localized nature of pancake bonds and the formation of a singlet dimer of the ligand. The spin of CuII within the Kagomé arrangement dominates the paramagnetism of the MOF, leading to strong geometrical magnetic frustration

    Conductive Stimuli-Responsive Coordination Network Linked with Bismuth for Chemiresistive Gas Sensing

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    This paper describes the design, synthesis, characterization, and performance of a novel semiconductive crystalline coordination network, synthesized using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) ligands interconnected with bismuth ions, toward chemiresistive gas sensing. Bi(HHTP) exhibits two distinct structures upon hydration and dehydration of the pores within the network, Bi(HHTP)-α and Bi(HHTP)-β, respectively, both with unprecedented network topology (2,3-c and 3,4,4,5-c nodal net stoichiometry, respectively) and unique corrugated coordination geometries of HHTP molecules held together by bismuth ions, as revealed by a crystal structure resolved via microelectron diffraction (MicroED) (1.00 Å resolution). Good electrical conductivity (5.3 × 10–3 S·cm–1) promotes the utility of this material in the chemical sensing of gases (NH3 and NO) and volatile organic compounds (VOCs: acetone, ethanol, methanol, and isopropanol). The chemiresistive sensing of NO and NH3 using Bi(HHTP) exhibits limits of detection 0.15 and 0.29 parts per million (ppm), respectively, at low driving voltages (0.1–1.0 V) and operation at room temperature. This material is also capable of exhibiting unique and distinct responses to VOCs at ppm concentrations. Spectroscopic assessment via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopic methods (i.e., attenuated total reflectance-infrared spectroscopy (ATR-IR) and diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS)), suggests that the sensing mechanisms of Bi(HHTP) to VOCs, NO, and NH3 comprise a complex combination of steric, electronic, and protic properties of the targeted analytes

    A Minimal Functional Complex of Cytochrome P450 and FBD of Cytochrome P450 Reductase in Nanodiscs

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    Structural interactions that enable electron transfer to cytochromeâ P450 (CYP450) from its redox partner CYP450â reductase (CPR) are a vital prerequisite for its catalytic mechanism. The first structural model for the membraneâ bound functional complex to reveal interactions between the fullâ length CYP450 and a minimal domain of CPR is now reported. The results suggest that anchorage of the proteins in a lipid bilayer is a minimal requirement for CYP450 catalytic function. Akin to cytochromeâ b5 (cytâ b5), Argâ 125 on the Câ helix of CYP450s is found to be important for effective electron transfer, thus supporting the competitive behavior of redox partners for CYP450s. A general approach is presented to study proteinâ protein interactions combining the use of nanodiscs with NMR spectroscopy and SAXS. Linking structural details to the mechanism will help unravel the xenobiotic metabolism of diverse microsomal CYP450s in their native environment and facilitate the design of new drug entities.Solving a structure of the cytochrome P450 (CYP450) complex with its redox partner is a vital prerequisite to understand the selective route of electron transfer. Structural interactions of CYP450â redox partner complex anchored in lipid membrane are a minimal requirement for functionality (electron transfer). This study unravels the drug/xenobiotic metabolism by diverse microsomal CYPs in their native membrane environment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144586/1/anie201802210.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144586/2/anie201802210_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144586/3/anie201802210-sup-0001-misc_information.pd

    A multi- and mixed-method adaptation study of a patient-centered perioperative mental health intervention bundle

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    BACKGROUND: Anxiety and depression are common among older adults and can intensify during perioperative periods, but few mental health interventions are designed for older surgical patients\u27 unique needs. As part of the feasibility trial, we developed and adapted a perioperative mental health (PMH) bundle for older patients comprised of behavioral activation (BA) and medication optimization (MO) to ameliorate anxiety and depressive symptoms before, during, and after cardiac, orthopedic, and oncologic surgery. METHODS: We used mixed-methods including workshop studios with patients, caregivers, clinicians, researchers, and interventionists; intervention refinement and reflection meetings; patient case review meetings; intervention session audio-recordings and documentation forms; and patient and caregiver semi-structured interviews. We used the results to refine our PMH bundle. We used multiple analytical approaches to report the nature of adaptations, including hybrid thematic analysis and content analysis informed by the Framework for Reporting Adaptations and Modifications - Expanded. RESULTS: Adaptations were categorized by content (intervention components), context (how the intervention is delivered, based on the study, target population, intervention format, intervention delivery mode, study setting, study personnel), training, and evaluation. Of 51 adaptations, 43.1% involved content, 41.2% involved context, and 15.7% involved training and evaluation. Several key adaptations were noted: (1) Intervention content was tailored to patient preferences and needs (e.g., rewording elements to prevent stigmatization of mental health needs; adjusting BA techniques and documentation forms to improve patient buy-in and motivation). (2) Cohort-specific adaptations were recommended based on differing patient needs. (3) Compassion was identified by patients as the most important element. CONCLUSIONS: We identified evidence-based mental health intervention components from other settings and adapted them to the perioperative setting for older adults. Informed by mixed-methods, we created an innovative and pragmatic patient-centered intervention bundle that is acceptable, feasible, and responsive to the needs of older surgical populations. This approach allowed us to identify implementation strategies to improve the reach, scalability, and sustainability of our bundle, and can guide future patient-centered intervention adaptations. CLINICAL TRIALS REGISTRATION: NCT05110690 (11/08/2021)

    Radiation Protection Using Single-Wall Carbon Nanotube Derivatives

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    This invention is a means of radiation protection, or cellular oxidative stress mitigation, via a sequence of quenching radical species using nano-engineered scaffolds, specifically single-wall carbon nanotubes (SWNTs) and their derivatives. The material can be used as a means of radiation protection by reducing the number of free radicals within, or nearby, organelles, cells, tissue, organs, or living organisms, thereby reducing the risk of damage to DNA and other cellular components (i.e., RNA, mitochondria, membranes, etc.) that can lead to chronic and/or acute pathologies, including but not limited to cancer, cardiovascular disease, immuno-suppression, and disorders of the central nervous system. In addition, this innovation could be used as a prophylactic or antidote for accidental radiation exposure, during high-altitude or space travel where exposure to radiation is anticipated, or to protect from exposure from deliberate terrorist or wartime use of radiation- containing weapons
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