Nanoporous Carbohydrate Metal–Organic Frameworks

Forgan, Ross S.,Smaldone, Ronald A.,Gassensmith, Jeremiah J.,Furukawa, Hiroyasu,Cordes, David B.,Li, Qiaowei,Wilmer, Christopher E.,Botros, Youssry Y.,Snurr, Randall Q.,Slawin, Alexandra M. Z.,Stoddar American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.1

<P>The binding of alkali and alkaline earth metal cations by macrocyclic and diazamacrobicyclic polyethers, composed of ordered arrays of hard oxygen (and nitrogen) donor atoms, underpinned the development of host–guest supramolecular chemistry in the 1970s and 1980s. The arrangement of −OCCO– and −OCCN– chelating units in these preorganized receptors, including, but not limited to, crown ethers and cryptands, is responsible for the very high binding constants observed for their complexes with Group IA and IIA cations. The cyclodextrins (CDs), cyclic oligosaccharides derived microbiologically from starch, also display this −OCCO– bidentate motif on both their primary and secondary faces. The self-assembly, in aqueous alcohol, of infinite networks of extended structures, which have been termed CD-MOFs, wherein γ-cyclodextrin (γ-CD) is linked by coordination to Group IA and IIA metal cations to form metal–organic frameworks (MOFs), is reported. CD-MOF-1 and CD-MOF-2, prepared on the gram-scale from KOH and RbOH, respectively, form body-centered cubic arrangements of (γ-CD)<SUB>6</SUB> cubes linked by eight-coordinate alkali metal cations. These cubic CD-MOFs are (i) stable to the removal of solvents, (ii) permanently porous, with surface areas of ∼1200 m<SUP>2</SUP> g<SUP>–1</SUP>, and (iii) capable of storing gases and small molecules within their pores. The fact that the −OCCO– moieties of γ-CD are not prearranged in a manner conducive to encapsulating single metal cations has led to our isolating other infinite frameworks, with different topologies, from salts of Na<SUP>+</SUP>, Cs<SUP>+</SUP>, and Sr<SUP>2+</SUP>. This lack of preorganization is expressed emphatically in the case of Cs<SUP>+</SUP>, where two polymorphs assemble under identical conditions. CD-MOF-3 has the cubic topology observed for CD-MOFs 1 and 2, while CD-MOF-4 displays a channel structure wherein γ-CD tori are perfectly stacked in one dimension in a manner reminiscent of the structures of some γ-CD solvates, but with added crystal stability imparted by metal–ion coordination. These new MOFs demonstrate that the CDs can indeed function as ligands for alkali and alkaline earth metal cations in a manner similar to that found with crown ethers. These inexpensive, green, nanoporous materials exhibit absorption properties which make them realistic candidates for commercial development, not least of all because edible derivatives, fit for human consumption, can be prepared entirely from food-grade ingredients.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2012/jacsat.2012.134.issue-1/ja208224f/production/images/medium/ja-2011-08224f_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja208224f'>ACS Electronic Supporting Info</A></P>

Polyporous Metal-Coordination Frameworks

Gassensmith, Jeremiah J.,Smaldone, Ronald A.,Forgan, Ross S.,Wilmer, Christopher E.,Cordes, David B.,Botros, Youssry Y.,Slawin, Alexandra M. Z.,Snurr, Randall Q.,Stoddart, J. Fraser American Chemical Society 2012 ORGANIC LETTERS Vol.14 No.6

<P>Starting from a chiral building block?α-cyclodextrin?and rubidium salts, the crystallization of a complex of chiral helices, which constitute a “green” porous coordination polymer, has been realized. Cyclodextrin molecules coordinated by rubidium ions form porous, infinitely long left-handed helical channels, interdigitated with each other. A theoretical examination of the potential of this new material to act as a medium for chiral separation is presented.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2012/orlef7.2012.14.issue-6/ol300199a/production/images/medium/ol-2012-00199a_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol300199a'>ACS Electronic Supporting Info</A></P>

In Situ Evaluation of a Visnir Penetrometer for Soil Characterization

Matteo Poggio,David J. Brown,Ross S. Bricklemyer 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Safe implementation of transoral incisionless fundoplication as a new technique in a tertiary care center

Shivanand Bomman,Sofya Malashanka,Adil Ghafoor,David J. Sanders,Shayan Irani,Richard A. Kozarek,Andrew Ross,Michal Hubka,Rajesh Krishnamoorthi 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.5

Background/Aims: Transoral incisionless fundoplication (TIF) is an accepted anatomic treatment for gastroesophageal reflux disease in selected patients. In this report, we analyze our institution’s programmatic allocation of resources during the safe implementation of TIF as a new procedure. Methods: A retrospective analysis of all patients who underwent TIF from January 2020 to February 2021 at our institution was per- formed. The process of initially allocating the operating room (OR) with overnight admission and postoperative esophagram for added safety, and subsequently transitioning TIF to the endoscopy suite (ES) as an outpatient procedure was described. Patient safety and out- comes were evaluated during transition. Results: Thirty patients who underwent TIF were identified. The mean age was 51.2±16.0 years. TIF was performed in an OR in nine patients (30%) and 21 (70%) in the ES. All the OR patients were admitted overnight and had routine esophagogram. In contrast, four (19%) from the ES group required clinically-indicated admission and three (14.2%) required esophagram. The mean procedure dura- tion was significantly lower in the ES group (65.7 min vs. 84 min, p=0.02). Conclusions: A stepwise, resource-efficient process was described that allowed safe initiation of TIF as a new technique and its effec- tive transition to a fully outpatient procedure.

Surgical revascularization for Moyamoya disease in the United States: A cost-effectiveness analysis

Wali Arvin R.,Santiago-Dieppa David. R.,Srinivas Shanmukha,Brandel Michael G.,Steinberg Jeffrey A.,Rennert Robert C,Mandeville Ross,Murphy James D.,Olson Scott,Pannell J. Scott,Khalessi Alexander A. 대한뇌혈관외과학회 2021 Journal of Cerebrovascular and Endovascular Neuros Vol.23 No.1

Objective Moyamoya disease (MMD) is a vasculopathy of the internal carotid arteries with ischemic and hemorrhagic sequelae. Surgical revascularization confers upfront peri-procedural risk and costs in exchange for long-term protective benefit against hemorrhagic disease. The authors present a cost-effectiveness analysis (CEA) of surgical versus non-surgical management of MMD. Methods A Markov Model was used to simulate a 41-year-old suffering a transient ischemic attack (TIA) secondary to MMD and now faced with operative versus nonoperative treatment options. Health utilities, costs, and outcome probabilities were obtained from the CEA registry and the published literature. The primary outcome was incremental cost-effectiveness ratio which compared the quality adjusted life years (QALYs) and costs of surgical and nonsurgical treatments. Base-case, one-way sensitivity, two-way sensitivity, and probabilistic sensitivity analyses were performed with a willingness to pay threshold of $50,000. Results The base case model yielded 3.81 QALYs with a cost of $99,500 for surgery, and 3.76 QALYs with a cost of $106,500 for nonsurgical management. One-way sensitivity analysis demonstrated the greatest sensitivity in assumptions to cost of surgery and cost of admission for hemorrhagic stroke, and probabilities of stroke with no surgery, stroke after surgery, poor surgical outcome, and death after surgery. Probabilistic sensitivity analyses demonstrated that surgical revascularization was the cost-effective strategy in over 87.4% of simulations. Conclusions Considering both direct and indirect costs and the postoperative QALY, surgery is considerably more cost-effective than non-surgical management for adults with MMD.

Remote monitoring using donor-derived, cell-free DNA after kidney transplantation during the coronavirus disease 2019 pandemic

( Steven R. Potter ),( Randall Hinojosa ),( Cliff D. Miles ),( Dan O’brien ),( David J. Ross ) 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.4

Background: Donor-derived, cell-free DNA (dd-cfDNA) level correlates with allograft injury with clinical validity and utility for quiescence and active acute rejection (AR) in kidney transplant recipients. We analyzed trends in dd-cfDNA level immediately preceding and during the coronavirus disease 2019 (COVID-19) pandemic with implemented “shelter in place” and a tele-health strategy with remote home phlebotomy to limit COVID-19 exposure. Methods: During COVID-19 in the United States (US), we surveyed weekly (January 6, 2020-May 25, 2020) metrics for dd-cfDNA corresponding to both a low risk for active rejection (dd-cfDNA < 0.5%) and cohorts with indeterminate levels of 0.5% to 1.0% and > 1.0%. During the study timeframe, over 11,000 patient samples (67%) from 150 kidney transplantation centers were transitioned from standard facility-based to remote phlebotomy. Results: The proportion of dd-cfDNA samples, analyzed in 21 weekly aggregated cohorts by risk-stratification category, was unchanged during the COVID-19 escalation in the US. Linearized slopes for numbers of samples corresponding to indeterminate risk for AR cohorts of > 1.0% and 0.5% to 1.0% were -0.31 and -0.12, respectively; indicating that prevalence of these “at risk for AR cohorts” decreased during remote surveillance. Approximately 73% of samples corresponded to low risk of AR (dd-cfDNA < 0.5%), while an additional 15% of samples had dd-cfDNA level ≤ 1.0%. Conclusion: The combination of remote home phlebotomy including dd-cfDNA analysis and a tele-health program offer a new paradigm that may substantially improve patient compliance and assuage anxiety regarding the state of kidney allograft health during the COVID-19 pandemic. Further prospective multi-center studies with robust outcomes data are warranted.