Catalytic properties of pristine and defect-engineered Zr-MOF-808 metal organic frameworks

[EN] Various defect-engineered Zr-trimesate MOF-808 compounds (DE-MOF-808) have been prepared by mixing the tricarboxylate ligands with dicarboxylate ligands; viz. isophthalate, pyridine-3,5-dicarboxylate, 5-hydroxy-isophthalate, or 5-amino-isophthalate. The resulting mixed-ligand compounds, MOF-808-X (X = IP, Pydc, OH or NH2) were all found to be highly crystalline and isostructural to the unmodified MOF-808. Pristine MOF-808 showed better catalytic performance than a UiO-66 reference compound for the Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl compounds. This was attributed to a higher availability of coordinatively unsaturated Zr4+ sites (cus) in MOF-808 upon removal of formate ions. Meanwhile, cus in UiO-66 are only located at defect sites and are thus much less abundant. Further improvement of the catalytic activity of defect-engineered MOF-808-IP and MOF-808-Pydc was observed, which may be related with the occurrence of less crowded Zr4+ sites in DE-MOF-808. The wider pore structure of MOF-808 with respect to UiO-66 compounds translates into a sharp improvement of the activity for the MPV reduction of bulky substrates, as shown for estrone reduction to estradiol. Interestingly, MOF-808 produces a notable diastereoselectivity towards the elusive 17--hydroxy estradiol.This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 641887 (project acronym: DEFNET). Financial support from the Spanish Ministry of Economy and Competitiveness (program Severo Ochoa SEV20120267), the Spanish Ministry of Science and Innovation (project MAT2014-52085-C2-1-P), and the German Research Foundation (project KA 1698/19-1) is also gratefully acknowledged. The Microscopy Service of the Universitat Politecnica de Valencia are gratefully acknowledged for the SEM images.Mautschke, H.; Drache, F.; Senkovska, I.; Kaskel, S.; Llabrés I Xamena, FX. (2018). Catalytic properties of pristine and defect-engineered Zr-MOF-808 metal organic frameworks. Catalysis Science & Technology. 8(14):3610-3616. https://doi.org/10.1039/c8cy00742jS3610361681

Mechanistic insights into the reversible lithium storage in an open porous carbon via metal cluster formation in all solid-state batteries

Porous carbons are promising anode materials for next generation lithium batteries due to their large lithium storage capacities. However, their high voltage slope during lithiation and delithiation as well as capacity fading due to intense formation of solid electrolyte interphase (SEI) limit their gravimetric and volumetric energy densities. Herein we compare a microporous carbide-derived carbon material (MPC) as promising future anode for all solid-state batteries with a commercial high-performance hard carbon anode. The MPC obtains high and reversible lithiation capacities of 1000 mAh g−1carbon in half-cells exhibiting an extended plateau region near 0 V vs. Li/Li+ preferable for full-cell application. The well-defined micro porosity of the MPC with a specific surface area of >1500 m2 g−1 combines well with the argyrodite-type electrolyte (Li6PS5Cl) suppressing extensive SEI formation to deliver high coulombic efficiencies. Preliminary full-cell measurements vs. nickel-rich NMC-cathodes (LiNi0.9Co0.05Mn0.05O2) provide a considerably improved average potential of 3.76 V leading to a projected energy density as high as 449 Wh kg−1 and reversible cycling for more than 60 cycles. 7Li Nuclear Magnetic Resonance spectroscopy was combined with ex-situ Small Angle X-ray Scattering to elucidate the storage mechanism of lithium inside the carbon matrix. The formation of extended quasi-metallic lithium clusters after electrochemical lithiation was revealed

Zinc Coordination Polymers Containing Isomeric Forms of p-(Thiazolyl)benzoic Acid: Blue-Emitting Materials with a Solvatochromic Response to Water

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Two coordination polymers of assorted dimensionality (1D, 2D) have been prepared, namely [Zn 3 (L 2Th ) 4 (OH) 2 ·2(HL 2Th )] ∞ (1) and [Zn(L 5Th )(OAc)] ∞ (2), starting from Zn II salts and the isomeric forms of the organic linker p-(thiazolyl)benzoic acid: p-(2-thiazolyl)benzoic acid (HL 2Th ) and p-(5-thiazolyl)benzoic acid (HL 5Th ). The isomers have been prepared ad hoc, following straightforward Pd-catalyzed C–C coupling reaction protocols. In 1, the deprotonated ligand is coordinated through its carboxylate group only, with dangling thiazole groups. The –COO – units are bridging adjacent metal centers, thus creating a 1D chain. The Zn 3 cluster is made of one six-coordinate (O h ) and two four-coordinate (T d ) Zn II ions; triple-bridging µ 3 -OH groups are balancing the overall positive charge. The structure of 2 is instead made of Zn 2 (carboxylate) 4 “paddle-wheel” dimers as the constituting inorganic node. The octahedral metal coordination sphere includes two µ-(κ-COO) benzoate spacers, two µ-(κ-COO) acetate ions, the thiazole N atoms coming from adjacent building blocks, and a weak Zn···Zn axial interaction. The resulting final assembly is two-dimensional (2D), where p-(5-thiazolyl)benzoate adopts a genuine µ-[κ(COO):κ(N)] bridging coordination mode. The luminescent properties of both polymers have been analyzed in the solid state; they feature ligand-centered emissions at λ = 434 nm (1) and λ = 427 nm (2). These electronic transitions fall in the visible region, giving the samples a characteristic blue color under an ordinary UV lamp (excitation at λ = 254 nm). The theoretical analysis of the electronic features of the ligands and related molecular orbitals reveals that the observed transitions are mainly of π→π* nature, involving π orbitals delocalized on both aromatic cycles. A significant (reversible) blueshift of the emission maximum of ca. 60 nm, from the visible to the UV region, has been observed for 1 when suspended in water

Diffusion study by IR micro-imaging of molecular uptake and release on mesoporous zeolites of structure type CHA and LTA

The presence of mesopores in the interior of microporous particles may significantly improve their transport properties. Complementing previous macroscopic transient sorption experiments and pulsèd field gradient NMR self-diffusion studies with such materials, the present study is dedicated to an in-depth study of molecular uptake and release on the individual particles of mesoporous zeolitic specimens, notably with samples of the narrow-pore structure types, CHA and LTA. The investigations are focused on determining the time constants and functional dependences of uptake and release. They include a systematic variation of the architecture of the mesopores and of the guest molecules under study as well as a comparison of transient uptake with blocked and un-blocked mesopores. In addition to accelerating intracrystalline mass transfer, transport enhancement by mesopores is found to be, possibly, also caused by a reduction of transport resistances on the particle surfaces. © 2013 by the authors; licensee MDPI, Basel, Switzerland.118181sciescopu

Growth hormone axis in chronic kidney disease

Chronic kidney disease (CKD) in children is associated with dramatic changes in the growth hormone (GH) and insulin-like growth factor (IGF-1) axis, resulting in growth retardation. Moderate-to-severe growth retardation in CKD is associated with increased morbidity and mortality. Renal failure is a state of GH resistance and not GH deficiency. Some mechanisms of GH resistance are: reduced density of GH receptors in target organs, impaired GH-activated post-receptor Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling, and reduced levels of free IGF-1 due to increased inhibitory IGF-binding proteins (IGFBPs). Treatment with recombinant human growth hormone (rhGH) has been proven to be safe and efficacious in children with CKD. Even though rhGH has been shown to improve catch-up growth and to allow the child to achieve normal adult height, the final adult height is still significantly below the genetic target. Growth retardation may persist after renal transplantation due to multiple factors, such as steroid use, decreased renal function and an abnormal GH–IGF1 axis. Those below age 6 years are the ones to benefit most from transplantation in demonstrating acceleration in linear growth. Newer treatment modalities targeting the GH resistance with recombinant human IGF-1 (rhIGF-1), recombinant human IGFBP3 (rhIGFBP3) and IGFBP displacers are under investigation and may prove to be more effective in treating growth failure in CKD

Text Messaging for Disease Monitoring in Childhood Nephrotic Syndrome

Introduction: There is limited information on effective disease monitoring for prompt interventions in childhood nephrotic syndrome. We examined the feasibility and effectiveness of a novel text messaging system (SMS) for disease monitoring in a multicenter, prospective study. Methods: A total of 127 patients <19 years with incident nephrotic syndrome were enrolled in the ongoing Nephrotic Syndrome Study Network between June 2015 and March 2018. Text messages soliciting home urine protein results, symptoms, and medication adherence were sent to a designated caregiver (n = 116) or adolescent patient (n = 3). Participants responded by texting. Feasibility of SMS was assessed by SMS adoption, retention, and engagement, and concordance between participant-reported results and laboratory/clinician assessments. The number of disease relapses and time-to-remission data captured by SMS were compared with data collected by conventional visits. Results: A total of 119 of 127 (94%) patients agreed to SMS monitoring. Retention rate was 94%, with a median follow-up of 360 days (interquartile range [IQR] 353–362). Overall engagement was high, with a median response rate of 87% (IQR, 68–97). Concordance between SMS-captured home urine protein results and edema status with same-day in-person study visit was excellent (kappa values 0.88 and 0.92, respectively). SMS detected a total of 108 relapse events compared with 41 events captured by scheduled visits. Median time to remission after enrollment was 22 days as captured by SMS versus 50 days as captured by scheduled visits. Conclusion: SMS was well accepted by caregivers and adolescent patients and reliably captured nephrotic syndrome disease activity between clinic visits. Additional studies are needed to explore the impact of SMS on disease outcomes

Immune Cell Recruitment and Cell-Based System for Cancer Therapy

Immune cells, such as cytotoxic T lymphocytes, natural killer cells, B cells, and dendritic cells, have a central role in cancer immunotherapy. Conventional studies of cancer immunotherapy have focused mainly on the search for an efficient means to prime/activate tumor-associated antigen-specific immunity. A systematic understanding of the molecular basis of the trafficking and biodistribution of immune cells, however, is important for the development of more efficacious cancer immunotherapies. It is well established that the basis and premise of immunotherapy is the accumulation of effective immune cells in tumor tissues. Therefore, it is crucial to control the distribution of immune cells to optimize cancer immunotherapy. Recent characterization of various chemokines and chemokine receptors in the immune system has increased our knowledge of the regulatory mechanisms of the immune response and tolerance based on immune cell localization. Here, we review the immune cell recruitment and cell-based systems that can potentially control the systemic pharmacokinetics of immune cells and, in particular, focus on cell migrating molecules, i.e., chemokines, and their receptors, and their use in cancer immunotherapy