The imine linkages of two layered, porous covalent organic frameworks (COFs), TPB-TP-COF (C6H3(C6H4N)32C6H4(CH)23, 1) and 4PE-1P-COF (C2(C6H4N)4C6H4(CH)22, 2), have been transformed into amide ...linkages to make the respective isostructural amide COFs 1′ and 2′ by direct oxidation with retention of crystallinity and permanent porosity. Remarkably, the oxidation of both imine COFs is complete, as assessed by FT-IR and 13C CP-MAS NMR spectroscopy and demonstrates (a) the first chemical conversion of a COF linkage and (b) how the usual “crystallization problem” encountered in COF chemistry can be bypassed to access COFs, such as these amides, that are typically thought to be difficult to obtain by the usual de novo methods. The amide COFs show improved chemical stability relative to their imine progenitors.
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The use of two primary alkylamine functionalities covalently tethered to the linkers of IRMOF-74-III results in a material that can uptake CO2 at low pressures through a chemisorption mechanism. In ...contrast to other primary amine-functionalized solid adsorbents that uptake CO2 primarily as ammonium carbamates, we observe using solid state NMR that the major chemisorption product for this material is carbamic acid. The equilibrium of reaction products also shifts to ammonium carbamate when water vapor is present; a new finding that has impact on control of the chemistry of CO2 capture in MOF materials and one that highlights the importance of geometric constraints and the mediating role of water within the pores of MOFs.
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It remains difficult to understand the surface of solid acid catalysts at the molecular level, despite their importance for industrial catalytic applications. A sulfated zirconium-based metal-organic ...framework, MOF-808-SO
, was previously shown to be a strong solid Brønsted acid material. In this report, we probe the origin of its acidity through an array of spectroscopic, crystallographic and computational characterization techniques. The strongest Brønsted acid site is shown to consist of a specific arrangement of adsorbed water and sulfate moieties on the zirconium clusters. When a water molecule adsorbs to one zirconium atom, it participates in a hydrogen bond with a sulfate moiety that is chelated to a neighbouring zirconium atom; this motif, in turn, results in the presence of a strongly acidic proton. On dehydration, the material loses its acidity. The hydrated sulfated MOF exhibits a good catalytic performance for the dimerization of isobutene (2-methyl-1-propene), and achieves a 100% selectivity for C8 products with a good conversion efficiency.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Autologous transplantation of patient-specific induced pluripotent stem cell (iPSC)-derived neurons is a potential clinical approach for treatment of neurological disease. Preclinical demonstration ...of long-term efficacy, feasibility, and safety of iPSC-derived dopamine neurons in non-human primate models will be an important step in clinical development of cell therapy. Here, we analyzed cynomolgus monkey (CM) iPSC-derived midbrain dopamine neurons for up to 2 years following autologous transplantation in a Parkinson’s disease (PD) model. In one animal, with the most successful protocol, we found that unilateral engraftment of CM-iPSCs could provide a gradual onset of functional motor improvement contralateral to the side of dopamine neuron transplantation, and increased motor activity, without a need for immunosuppression. Postmortem analyses demonstrated robust survival of midbrain-like dopaminergic neurons and extensive outgrowth into the transplanted putamen. Our proof of concept findings support further development of autologous iPSC-derived cell transplantation for treatment of PD.
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•A non-human primate model tests cell transplantation for PD therapy•Autologous iPSC dopamine neurons can provide long-term functional recovery•Transplanted cells survive for up to 2 years and reinnervate the host brain
A pre-clinical test of transplantation of autologous iPSC-derived dopamine neurons in a cynomolgus monkey model of Parkinson’s disease provides proof of principle for long-term innervation and functional benefit without a requirement for immunosuppression.
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There is increasing evidence that patients with Coronavirus disease 19 (COVID‐19) present with neurological and psychiatric symptoms. Anosmia, hypogeusia, headache, nausea and altered consciousness ...are commonly described, although there are emerging clinical reports of more serious and specific conditions such as acute cerebrovascular accident, encephalitis and demyelinating disease. Whether these presentations are directly due to viral invasion of the central nervous system (CNS) or caused by indirect mechanisms has yet to be established. Neuropathological examination of brain tissue at autopsy will be essential to establish the neuro‐invasive potential of the SARS‐CoV‐2 virus but, to date, there have been few detailed studies. The pathological changes in the brain probably represent a combination of direct cytopathic effects mediated by SARS‐CoV‐2 replication or indirect effects due to respiratory failure, injurious cytokine reaction, reduced immune response and cerebrovascular accidents induced by viral infection. Further large‐scale molecular and cellular investigations are warranted to clarify the neuropathological correlates of the neurological and psychiatric features seen clinically in COVID‐19. In this review, we summarize the current reports of neuropathological examination in COVID‐19 patients, in addition to our own experience, and discuss their contribution to the understanding of CNS involvement in this disease.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
The management of sepsis has substantially improved over the past 15 years. In this study, early, goal-directed therapy, which focuses on the initial resuscitation efforts, was compared with usual ...care for the management of severe sepsis in the United Kingdom.
The incidence of severe sepsis and septic shock in adults is estimated to range from 56 to 91 per 100,000 population per year.
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Affected patients have high rates of death, complications, and resource utilization.
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Since 2002, the Surviving Sepsis Campaign (SSC) has promoted best practice, including early recognition, source control, appropriate and timely antibiotic administration, and resuscitation with intravenous fluids and vasoactive drugs.
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Resuscitation guidance is largely based on a 2001 single-center, proof-of-concept study by Rivers et al., which indicated that protocolized delivery of 6 hours of early, goal-directed therapy (EGDT) to patients presenting to the emergency department . . .
Herein, we demonstrate the first example of a multistep solid-state organic synthesis, in which a new imine-linked two-dimensional covalent organic framework (COF-170, 1) was transformed through ...three consecutive postsynthetic modifications into porous, crystalline cyclic carbamate and thiocarbamate-linked frameworks. These linkages are previously unreported and inaccessible through de novo synthesis. While not altering the overall connectivity of the framework, these chemical transformations induce significant conformational and structural changes at each step, highlighting the key importance of noncovalent interactions and conformational flexibility to COF crystallinity and porosity. These transformations were assessed using 15N multiCP-MAS NMR spectroscopy, providing the first quantitation of yields in COF postsynthetic modification reactions, as well as of amine defect sites in imine-linked COFs. This multistep COF linkage postsynthetic modification represents a significant step toward bringing the precision of organic solution-phase synthesis to extended solid-state compounds.
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The Way It Was Osborn, M.J
Annual review of microbiology,
09/2019, Volume:
73, Issue:
1
Journal Article
Peer reviewed
Open access
Mary Osborn was a native Californian. She was an undergraduate at the University of California, Berkeley, where she worked in the laboratory of I.L. Chaikoff. She received her PhD at the University ...of Washington, where her work on the role of folic acid coenzymes in one-carbon metabolism revealed the mechanism of action of methotrexate. After postdoctoral training with Bernard Horecker in the Department of Microbiology at New York University (NYU), she embarked on her research career as a faculty member in the NYU Department of Microbiology and in the Department of Molecular Biology at Albert Einstein College of Medicine. In 1968 she moved as one of the founding faculty of the new medical school of the University of Connecticut, where she remained until her retirement in 2014. Her research was focused on the biosynthesis of the endotoxin lipopolysaccharide (LPS) of gram-negative bacteria and on the assembly of the bacterial cell envelope. She made seminal contributions in these areas. She was the recipient of numerous honors and served as president of several important scientific organizations. Later in her career she served as chair of the National Research Council Committee on Space Biology and Medicine, advisory to the National Aeronautics and Space Administration (NASA), which produced an influential report that plotted the path for NASA's space biology research program in the first decade of the twenty-first century. Dr. Osborn died on Jan. 17, 2019.
Sequence-Dependent Materials Osborn Popp, Thomas M; Yaghi, Omar M
Accounts of chemical research,
03/2017, Volume:
50, Issue:
3
Journal Article
Peer reviewed
Sequence-dependent materials are a class of materials in which a compositionally aperiodic apportionment of functional groups leads to properties where the whole performs better than the sum of the ...parts. Here, we discuss what defines a sequence-dependent material, and how the concept can be realized in crystals of extended structures such as metal–organic frameworks.
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Abstract Astrocytes and microglia become reactive in many neurological disorders resulting in phenotypic and functional alterations. Both cell types might also display functional changes during ...normal aging. To identify gene signatures and changes in basal cellular functions of astrocytes and microglia in relation to aging, we isolated viable astrocytes and microglia from young adult and aged mouse cortices and determined their gene expression profile. Aged astrocytes, compared with young astrocytes, showed an increased inflammatory phenotype and increased ‘zinc ion binding.’ Young astrocytes showed higher expression of genes involved in ‘neuronal differentiation’ and hemoglobin synthesis. Astrocyte expression of genes involved in neuronal signaling remains high throughout age. Aged microglia had higher expression of genes involved in ‘vesicle release,’ ‘zinc ion binding,’ and genes within the tumor necrosis factor-ligand family and young microglia had increased transcript levels of C-C motif chemokines. These data provide a transcriptome database of cell-type enriched genes of astrocytes and microglia from adult mice and give insight into the differential gene signature of astrocytes and microglia in relation to normal aging.
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