Fabrication of MOF Films of UiO or PCN Type Through Layer-by-Layer Molecular Deposition as well as Bulk Deposition for Catalytic Applications

Metal-organic frameworks (MOFs) are crystalline, porous materials comprised of symmetric organic linkers coordinated to positively charged metal atoms or metal oxide nodes. This dissertation uses strategies in crystal engineering to advance the study of functional MOFs with emphasis on thin film deposition. The first chapter of this dissertation will introduce the field of reticular chemistry to the reader and describe synthetic efforts to develop useful building blocks for MOF materials: namely porphyrin macrocycles and carboxylate capped zirconium-oxo and hafnium-oxo clusters. The building blocks for MOFs developed in the first chapter will be employed in the second and third chapters through incorporation into MOF thin films through molecular deposition and bulk deposition respectively. New methods for the molecular deposition of Hf-based MOF films are described which will expand the available MOF types which are known to be deposited in a molecular layer-by-layer fashion. A key methodology is the use of Hf-oxo clusters capped by carboxylate ligands to be used as a potential Hf source for molecular layer-by-layer Hf-MOF deposition. Using an automated epitaxial workstation, films of UiO-66 (Hf) are fabricated for the first time and porphyrinic Hf-based MOFs are developed for catalytic applications. Following these efforts, experiments regarding the bulk-deposition of UiO-66 and UiO-66 (Hf) films are laid out. The UiO-66 (Hf) bulk deposited films are shown to be a promising catalyst for CO2 fixation to epoxides for cyclic carbonate synthesis

The Future of Personal Health Records in the Presence of Misaligned Incentives

We posit that the emergence of the independent personal health record (PHR) platforms is potentially a major development toward the cause of digitizing healthcare. Not only do these platforms empower the patients by giving them complete control over their records, but they also can help promote the adoption of electronic health records (EHRs) by healthcare providers. In a pluralistic healthcare system like that which exists in the United States, where many healthcare providers lack the incentive to adopt EHR and electronically share their patients’ records with competing providers, we believe that PHR platforms can facilitate the adoption and use of EHRs in the healthcare sector

Adoption of Electronic and Personal Health Records: An Ecconomic Analysis

We investigate strategic issues surrounding the adoption of electronic health records (EHR) and personal health records (PHR) using an economic framework. Through our analysis, we find evidence that health care providers do not have an incentive to implement interoperable EHR systems even though the implementation of EHR systems (interoperable or otherwise) will increase consumer surplus. In this context, we conjecture that PHR platforms can fundamentally alter the incentives of health care providers, potentially leading to increased EHR adoption under some conditions. In a pluralistic health care system like that which exists in the United States, where health care providers have varying incentives to implement interoperable electronic health records, an online PHR platform can provide an alternative means for consumers to freely exchange their health records among different providers

Investigation of polyviologens as oxygen indicators in food packaging

A triggered oxygen indicator, formulated from a combination of electrochrome, titanium dioxide and EDTA, was evaluated for use in modified atmosphere packaging. Methylene blue was not an ideal electrochrome due to its slow reduction to the leuco form and fast subsequent oxidation by oxygen present at low concentrations, >0.1%. Polyviologen electrochromes showed much faster reduction after exposure to UV light. Thionine and 2,2?-dicyano-1,1?-dimethylviologen dimesylate, which have more anodic reduction potentials compared to methylene blue, can be used to produce oxygen indicators with decreased sensitivity to oxygen. These indicators can be used to detect oxygen even when levels increase up to 4.0%

Mutant NADH dehydrogenase subunit 4 gene delivery to mitochondria by targeting sequence-modified adeno-associated virus induces visual loss and optic atrophy in mice

Although mutated G11778A NADH ubiquinone oxidoreductase subunit 4 (ND4) mitochondrial DNA (mtDNA) is firmly linked to the blindness of Leber hereditary optic neuropathy (LHON), a bona fide animal model system with mutated mtDNA complex I subunits that would enable probing the pathogenesis of optic neuropathy and testing potential avenues for therapy has yet to be developed. The mutant human ND4 gene with a guanine to adenine transition at position 11778 with an attached FLAG epitope under control of the mitochondrial heavy strand promoter (HSP) was inserted into a modified self-complementary (sc) adeno-associated virus (AAV) backbone. The HSP-ND4FLAG was directed toward the mitochondria by adding the 23 amino acid cytochrome oxidase subunit 8 (COX8) presequence fused in frame to the N-terminus of green fluorescent protein (GFP) into the AAV2 capsid open reading frame. The packaged scAAV-HSP mutant ND4 was injected into the vitreous cavity of normal mice (OD). Contralateral eyes received scAAV-GFP (OS). Translocation and integration of mutant human ND4 in mouse mitochondria were assessed with PCR, reverse transcription-polymerase chain reaction (RT-PCR), sequencing, immunoblotting, and immunohistochemistry. Visual function was monitored with serial pattern electroretinography (PERG) and in vivo structure with spectral domain optical coherence tomography (OCT). Animals were euthanized at 1 year and processed for light and transmission electron microscopy. The PCR products of the mitochondrial and nuclear DNA extracted from infected retinas and optic nerves gave the expected 500 base pair bands. RT-PCR confirmed transcription of the mutant human ND4 DNA in mice. DNA sequencing confirmed that the PCR and RT-PCR products were mutant human ND4 (OD only). Immunoblotting revealed the expression of mutant ND4FLAG (OD only). Pattern electroretinograms showed a significant decrement in retinal ganglion cell function OD relative to OS at 1 month and 6 months after AAV injections. Spectral domain optical coherence tomography showed optic disc edema starting at 1 month post injection followed by optic nerve head atrophy with marked thinning of the inner retina at 1 year. Histopathology of optic nerve cross sections revealed reductions in the optic nerve diameters of OD versus OS where transmission electron microscopy revealed significant loss of optic nerve axons in mutant ND4 injected eyes where some remaining axons were still in various stages of irreversible degeneration with electron dense aggregation. Electron lucent mitochondria accumulated in swollen axons where fusion of mitochondria was also evident. Due to the UGA codon at amino acid 16, mutant G11778A ND4 was translated only in the mitochondria where its expression led to significant loss of visual function, loss of retinal ganglion cells, and optic nerve degeneration recapitulating the hallmarks of human LHON

Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data.

BackgroundAlthough studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.MethodsWe used preterm baboons, mice, and humans (≤276/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.ResultsIn mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K+ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤256/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.ConclusionsWe speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth

MENA-SINO Consensus Statement on Implementing Care Pathways for Acute Neurovascular Emergencies During the COVID-19 Pandemic

In the unprecedented current era of the COVID-19 pandemic, challenges have arisen in the management and interventional care of patients with acute stroke and large vessel occlusion, aneurysmal subarachnoid hemorrhage, and ruptured vascular malformations. There are several challenges facing endovascular therapy for stroke, including shortages of medical staff who may be deployed for COVID-19 coverage or who may have contracted the infection and are thus quarantined, patients avoiding early medical care, a lack of personal protective equipment, delays in door-to-puncture time, anesthesia challenges, and a lack of high-intensity intensive care unit and stroke ward beds. As a leading regional neurovascular organization, the Middle East North Africa Stroke and Interventional Neurotherapies Organization (MENA-SINO) has established a task force composed of medical staff and physicians from different disciplines to establish guiding recommendations for the implementation of acute care pathways for various neurovascular emergencies during the current COVID-19 pandemic. This consensus recommendation was achieved through a series of meetings to finalize the recommendation. © Copyright © 2020 Al-Jehani, John, Hussain, Al Hashmi, Alhamid, Amr, Ozdemir, Shuaib, Alhazzani, Ghorbani, Mansour and Saqqur

Assessment of the sensitivity of model responses to urban emission changes in support of emission reduction strategies

© 2023 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/The sensitivity of air quality model responses to modifications in input data (e.g. emissions, meteorology and boundary conditions) or model configurations is recognized as an important issue for air quality modelling applications in support of air quality plans. In the framework of FAIRMODE (Forum of Air Quality Modelling in Europe, https://fairmode.jrc.ec.europa.eu/) a dedicated air quality modelling exercise has been designed to address this issue. The main goal was to evaluate the magnitude and variability of air quality model responses when studying emission scenarios/projections by assessing the changes of model output in response to emission changes. This work is based on several air quality models that are used to support model users and developers, and, consequently, policy makers. We present the FAIRMODE exercise and the participating models, and provide an analysis of the variability of O3 and PM concentrations due to emission reduction scenarios. The key novel feature, in comparison with other exercises, is that emission reduction strategies in the present work are applied and evaluated at urban scale over a large number of cities using new indicators such as the absolute potential, the relative potential and the absolute potency. The results show that there is a larger variability of concentration changes between models, when the emission reduction scenarios are applied, than for their respective baseline absolute concentrations. For ozone, the variability between models of absolute baseline concentrations is below 10%, while the variability of concentration changes (when emissions are similarly perturbed) exceeds, in some instances 100% or higher during episodes. Combined emission reductions are usually more efficient than the sum of single precursor emission reductions both for O3 and PM. In particular for ozone, model responses, in terms of linearity and additivity, show a clear impact of non-linear chemistry processes. This analysis gives an insight into the impact of model’ sensitivity to emission reductions that may be considered when designing air quality plans and paves the way of more in-depth analysis to disentangle the role of emissions from model formulation for present and future air quality assessments.Peer reviewe