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Nitric oxide (NO) and carbon monoxide (CO) are two important gasotransmitters with critical biological roles in the human body. Due to their short lifetime and dangerous side effects at high concentrations, it is essential to find safe storage and slow release methods of these two gases. Herein, we report the multi-scale simulations of two-dimensional (Zn)MOF-470 doped with antimicrobial Ag atoms to evaluate the degree of enhancement of adsorption and dynamics of NO and CO. The results show that NO binds to Ag stronger than CO. In addition, the decoration of the benzene ring with Ag atoms on both sides has led to the effective adsorption of NO and CO with binding energies of -26.34 and -21.71 kcal mol

A combined experimental and theoretical study of C2H2 and CO2 adsorption and separation was performed in two isostructural molecular porous materials (MPMs): MPM-1-Cl ([Cu2(adenine)4Cl2]Cl2) and MPM-1-TIFSIX ([Cu2(adenine)4(TiF6)2]). It was revealed that MPM-1-Cl displayed higher low-pressure uptake, isosteric heat of adsorption (Qst), and selectivity for C2H2 than CO2, whereas the opposite was observed for MPM-1-TIFSIX. While MPM-1-Cl contains only one type of accessible channel, which has a greater preference toward C2H2, MPM-1-TIFSIX contains three distinct accessible channels, one of which is a confined region between two large channels that represents the primary binding site for both adsorbates. According to molecular simulations, the initial adsorption site in MPM-1-TIFSIX interacts more strongly with CO2 than C2H2, thus explaining the inversion of adsorbate selectivity relative to MPM-1-Cl.

peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 17/08/2021 The stability of microporous metal–organic frameworks (MOFs) in moist environments must be taken into consideration for their practical implementations, which has been largely ignored thus far. Herein, we synthesized a new moisture-stable Zn-MOF, {[Zn2(SDB)2(L)2]·2DMA}n, IITKGP-12, by utilizing a bent organic linker 4,4′-sulfonyldibenzoic acid (H2SDB) containing a polar sulfone group (−SO2) and a N, N-donor spacer (L) with a Brunauer–Emmett–Teller surface area of 216 m2 g–1. This material displays greater CO2 adsorption capacity over N2 and CH4 with high IAST selectivity, which is also validated by breakthrough experiments with longer breakthrough times for CO2. Most importantly, the separation performance is largely unaffected in the presence of moisture of simulated flue gas stream. Temperature-programmed desorption (TPD) analysis shows the ease of the regeneration process, and the performance was verified for multiple cycles. In order to understand the structure–function relationship at the atomistic level, grand canonical Monte Carlo (GCMC) calculation was performed, indicating that the primary binding site for CO2 is between the sulfone moieties in IITKGP-12. CO2 is attracted to the bonded structure (V-shape) of the sulfone moieties in a perpendicular fashion, where CCO2 is aligned with S, and the CO2 axis bisects the SO2 axis. Thus, the strategic approach to immobilize the polar sulfone moiety with a high number of inherent stronger M–N coordination and the absence of coordination unsaturation made this MOF potential toward practical CO2 separation applications.

The high energy footprint of commodity gas purification and increasing demand for gases require new approaches to gas separation. Kinetic separation of gas mixtures through molecular sieving can enable separation by molecular size or shape exclusion. Physisorbents must exhibit the right pore diameter to enable separation, but the 0.3-0.4 nm range relevant to small gas molecules is hard to control. Herein, dehydration of the ultramicroporous metal-organic framework Ca-trimesate, Ca(HBTC)⋅H2 O (H3 BTC=trimesic acid), bnn-1-Ca-H2 O, affords a narrow pore variant, Ca(HBTC), bnn-1-Ca. Whereas bnn-1-Ca-H2 O (pore diameter 0.34 nm) exhibits ultra-high CO2 /N2 , CO2 /CH4 , and C2 H2 /C2 H4 binary selectivity, bnn-1-Ca (pore diameter 0.31 nm) offers ideal selectivity for H2 /CO2 and H2 /N2 under cryogenic conditions. Ca-trimesate, the first physisorbent to exhibit H2 sieving under cryogenic conditions, could be a prototype for a general approach to exert precise control over pore diameter in physisorbents.

Acetylene (C2 H2 ) capture is a step in a number of industrial processes, but it comes with a high-energy footprint. Although physisorbents have the potential to reduce this energy footprint, they are handicapped by generally poor selectivity versus other relevant gases, such as CO2 and C2 H4 . In the case of CO2 , the respective physicochemical properties are so similar that traditional physisorbents, such as zeolites, silica, and activated carbons cannot differentiate well between CO2 and C2 H2 . Herein, we report that a family of three isostructural, ultramicroporous (

A combined experimental and theoretical study of C

Physical adsorption of gas molecules in micro porous materials is an exothermic process, with desorption entropy driving a decrease in uptake with temperature. Enhanced gas sorption with increasing temperature is rare in porous materials and is indicative of sorbate initiated structural change. Here, sorption of C2H6, C3H6, and C3H8 in a flexible microporous metal-organic framework (MOF) {Cu-(FPBDC)]•DMF}n (NKU-FlexMOF-1) (H2FPBDC = 5-(5-fluoropyridin-3-yl)-1,3-benzenedicarboxylic acid) that increases with rising temperature over a practically useful temperature and pressure range is reported along with other small molecule and hydrocarbon sorption isotherms. Single X-ray diffraction studies, temperature-dependent gas sorption isotherms, in situ and variable temperature powder X-ray diffraction experiments, and electronic structure calculations were performed to characterize the conformation-dependent sorption behavior in NKU-FlexMOF-1. In total, the data supports that the atypical sorption behavior is a result of loading-dependent structural changes in the flexible framework of NKU-FlexMOF-1 induced by sorbate-specific guest framework interactions. The sorbates cause subtle adaptations of the framework distinct to each sorbate providing an induced-fit separation mechanism to resolve chemically similar hydrocarbons through highly specific sorbate sorbent interactions. The relevant intermolecular contacts are shown to be predominantly repulsion and dispersion interactions. NKU-FlexMOF-1 is also found to be stable in aqueous solutions including toleration of pH changes. These experiments demonstrate the potential of this flexible microporous MOF for cost and energy efficient industrial hydrocarbon separation and purification processes. The efficacy for the separation of C3H6/C3H8 mixtures is explicitly demonstrated using NKU-FlexMOF-1a (i.e., activated NKU-FlexMOF-1) for a particular useful temperature range.'

In the context of porous crystalline materials toward CO2 separation and capture, a new 2-fold interpenetrated 3D microporous Co-MOF, IITKGP-11 (IITKGP denotes Indian Institute of Technology Kharagpur), has been synthesized consisting of a 1D channel of ∼3.6 × 5.0 A2 along the [101] direction with a cavity volume of 35.20%. This microporous framework with a BET surface area of 253 m2g-1 shows higher uptake of CO2 (under 1 bar, 3.35 and 2.70 mmol g-1 at 273 and 295 K, respectively), with high separation selectivities for CO2/N2 and CO2/CH4 gas mixtures under ambient conditions as estimated through IAST calculation. Moreover, real time dynamic breakthrough studies reveal the high adsorption selectivity toward CO2 for these binary mixed gases at 295 K and 1 bar. Besides high gas separation selectivity, capacity considerations in mixed gas phases are also important to check the performance of a given adsorbent. CO2 loading amounts in mixed gas phases are quite high as predicted through IAST calculation and experimentally determined from dynamic breakthrough studies. In order to get insight into the phenomena, GCMC simulation was performed demonstrating that the CO2 molecules are electrostatically trapped via interactions between oxygen on CO2 and hydrogen on pyridyl moieties of the spacers.

The first sorbent with high CO2 selectivity and poor water affinity addresses need for trace CO2 remediation in confined spaces., CO2 accumulation in confined spaces represents an increasing environmental and health problem. Trace CO2 capture remains an unmet challenge because human health risks can occur at 1000 parts per million (ppm), a level that challenges current generations of chemisorbents (high energy footprint and slow kinetics) and physisorbents (poor selectivity for CO2, especially versus water vapor, and/or poor hydrolytic stability). Here, dynamic breakthrough gas experiments conducted upon the ultramicroporous material SIFSIX-18-Ni-β reveal trace (1000 to 10,000 ppm) CO2 removal from humid air. We attribute the performance of SIFSIX-18-Ni-β to two factors that are usually mutually exclusive: a new type of strong CO2 binding site and hydrophobicity similar to ZIF-8. SIFSIX-18-Ni-β also offers fast sorption kinetics to enable selective capture of CO2 over both N2 (SCN) and H2O (SCW), making it prototypal for a previously unknown class of physisorbents that exhibit effective trace CO2 capture under both dry and humid conditions.

Simulations of C2H2 sorption were performed in α-[Mg3(O2CH)6] and α-[Mn3(O2CH)6], two isostructural metal–organic frameworks (MOFs) that consist of a network of M2+ ions coordinated to formate linkers. Previous experimental studies revealed that both MOFs display high low-pressure uptake and isosteric heat of adsorption (Qst) for C2H2 [Samsonenko, D. G. et al. Chem. Asian J. 2007, 2, 484−488]. Simulations using two recently developed potential energy functions for the sorbate in both MOFs yielded sorption isotherms and Qst values that are in reasonable agreement with the corresponding experimental measurements. Electronic structure calculations revealed that the metal ions are more positively charged in α-[Mg3(O2CH)6] than in α-[Mn3(O2CH)6], which in turn led to greater partial negative charges on the linker O atoms in the Mg variant. This resulted in the former displaying a higher calculated C2H2 uptake than the latter for all state points considered, which is consistent with what was observed experiment...

Grand canonical Monte Carlo (GCMC) simulations of carbondioxide (CO$_2$) and acetylene (C$_2$H$_2$) sorption were performed in MPM-1-Cl and MPM-1-Br, two robust molecular porous materials (MPMs) that were synthesized by the addition of adenine to CuX$_2$ (X = Cl or Br) by solvent diffusion. Previous experimental studies revealed that both MPMs are selective for C$_2$H$_2$ over CO$_2$ [Xie DY, et al. (2017) ${CIESC J}$ 68: 154--162]. Simulations in MPM-1-Cl and MPM-1-Br were carried out using polarizable and nonpolarizable potentials of the respective sorbates; this was done to investigate the role of explicit induction on the gas sorption mechanism in these materials. The calculated sorption isotherms and isosteric heat of adsorption ($Q_{st}$) valuesfor both sorbates are in reasonable agreement with the corresponding experimental measurements, with simulations using the polarizable models producing the closest overall agreement. The modeled CO$_2$ binding sitein both MPMs was discovered as sorption between the halide ions of two adjacent [Cu$_2$(adenine)$_4$X$_2$]$^{2+}$ (X = Cl, Br) units.In the case of C$_2$H$_2$, it was found that the sorbate molecule prefers to align along the X--Cu--Cu--X axis of the copper paddlewheels suchthat each H atom of the C$_2$H$_2$ molecule can interact favorably with the coordinated X$^-$ ions. The simulations revealed that both MPMs exhibit stronger interactions with C$_2$H$_2$ than CO$_2$, which is consistent with experimental findings. The effect of halogen substitution toward CO$_2$ and C$_2$H$_2$ sorption in two isostructural MPMs was also elucidated in our theoretical studies.

rht-metal–organic frameworks (MOFs) represent a highly popular class of MOFs in the world of porous crystalline materials. MOFs belonging to this family consist of M2+ ions coordinated to hexatopic organic linkers containing three coplanar isophthalate-based moieties. rht-MOFs are a promising platform of MOFs because they display open-metal sites through the [M2(O2CR)4] clusters, high surface areas, and tunable pore sizes and chemical functionalities. They have been shown to exhibit high uptake for various energy-related gases, such as H2 and CO2. Detailed insights into the gas sorption mechanisms and binding sites in these MOFs can be made by way of experimental techniques, including neutron powder diffraction (NPD) and inelastic neutron scattering (INS), and theoretical methods, such as Monte Carlo (MC) simulations and electronic structure calculations. In this highlight, we review the important experimental and theoretical studies that have been performed to investigate the favorable gas sorption sites in these MOFs. A better understanding of the gas sorption mechanisms in rht-MOFs and related structures can allow for the rational design of new materials that are tailored for specific applications.

Background: Basic and clinical scientific research at the University of South Florida (USF) have intersected to support a multi-faceted approach around a common focus on rare iron-related diseases. We proposed a modified version of the National Center for Biotechnology Information’s (NCBI) Hackathon-model to take full advantage of local expertise in building “Iron Hack”, a rare disease-focused hackathon. As the collaborative, problem-solving nature of hackathons tends to attract participants of highly-diverse backgrounds, organizers facilitated a symposium on rare iron-related diseases, specifically porphyrias and Friedreich’s ataxia, pitched at general audiences. Methods: The hackathon was structured to begin each day with presentations by expert clinicians, genetic counselors, researchers focused on molecular and cellular biology, public health/global health, genetics/genomics, computational biology, bioinformatics, biomolecular science, bioengineering, and computer science, as well as guest speakers from the American Porphyria Foundation (APF) and Friedreich’s Ataxia Research Alliance (FARA) to inform participants as to the human impact of these diseases. Results: As a result of this hackathon, we developed resources that are relevant not only to these specific disease-models, but also to other rare diseases and general bioinformatics problems. Within two and a half days, “Iron Hack” participants successfully built collaborative projects to visualize data, build databases, improve rare disease diagnosis, and study rare-disease inheritance. Conclusions: The purpose of this manuscript is to demonstrate the utility of a hackathon model to generate prototypes of generalizable tools for a given disease and train clinicians and data scientists to interact more effectively.

Hydrogen sorption was characterized theoretically in NOTT-112, an rht-metal–organic framework (MOF) that consists of Cu2+ ions coordinated to 1,3,5-tris(3′,5′-dicarboxy[1,1′-biphenyl]-4-yl)benzene ligands. Grand canonical Monte Carlo (GCMC) simulations of H2 sorption were performed using three different sorbate potentials of increasing complexity to elucidate the mechanism of interaction in NOTT-112. Reasonable agreement with the experimental H2 sorption isotherms, isosteric heats of adsorption (Qst), and H2–Cu2+ distances was obtained with the model that includes explicit many-body polarization. This highlights the physical importance of induction in H2 sorption in MOFs with open-metal sites. The two Cu2+ ions within the paddlewheels in NOTT-112 have distinct electrostatic profiles and sorption characteristics. The Cu2+ ions projecting into the cuboctahedral (cub–Oh) cage of the MOF are more electropositive than the Cu2+ ions projecting toward the organic linker, and therefore serve as the initial loadin...

Simulations of CO2 and H2 sorption were performed in UTSA-20, a metal–organic framework (MOF) having zyg topology and composed of Cu2+ ions coordinated to 3,3′,3′′,5,5′,5′′-benzene-1,3,5-triyl-hexabenzoate (BHB) linkers. Previous experimental studies have shown that this MOF displays remarkable CO2 sorption properties and exhibits one of the highest gravimetric H2 uptakes at 77 K/1.0 atm (2.9 wt%) [Z. Guo, et al. Angew. Chem., Int. Ed., 2011, 50, 3178–3181]. For both sorbates, the simulations were executed with the inclusion of explicit many-body polarization interactions, which was necessary to reproduce sorption onto the open-metal sites. Non-polarizable potentials were also utilized for simulations of CO2 sorption as a control. The simulated excess sorption isotherms for both CO2 and H2 are in very good agreement with the corresponding experimental data over a wide range of temperatures and pressures, thus demonstrating the accuracy and predictive power of the polarizable potentials used herein. The theoretical isosteric heat of adsorption (Qst) values are also in good agreement with the newly reported experimental Qst values for the respective sorbates in UTSA-20. Sorption onto the more positively charged Cu2+ ion of the [Cu2(O2CR)4] cluster was observed for both CO2 and H2. However, a binding site with energetics comparable to that for an open-metal site was also discovered for both sorbates. A radial distribution function (g(r)) analysis about the preferential Cu2+ ions for CO2 and H2 revealed that both sorbates display different trends for the relative occupancy about such sites upon increasing/decreasing the pressure in the MOF. Overall, this study provides insights into the CO2 and H2 sorption mechanisms in this MOF containing open-metal sites and small pore sizes for the first time through a classical polarizable force field.

The etiology of autoimmune liver disease is poorly understood. BALB/c mice deficient in the immunoregulatory cytokine TGF-β1 spontaneously develop necroinflammatory liver disease, but the immune basis for the development of this pathology has not been demonstrated. Here, we show that BALB/c-TGF-β1−/− mice exhibit abnormal expansion in hepatic mononuclear cells (MNCs) compared with wild-type littermate control mice, particularly in the T cell and macrophage lineages. To test whether lymphocytes of the adaptive immune system are required for the spontaneous development of necroinflammatory liver disease, BALB/c-TGF-β1−/− mice were rendered deficient in B and T cells by crossing them with BALB/c-recombinase-activating gene 1−/− mice. BALB/c-TGF-β1−/−/recombinase-activating gene 1−/− double-knockout mice showed extended survival and did not develop necroinflammatory liver disease. The cytolytic activity of BALB/c-TGF-β1−/− hepatic lymphocytes was assessed using an in vitro CTL assay. CTL activity was much higher in BALB/c-TGF-β1−/− hepatic MNCs compared with littermate control hepatic MNCs and was particularly pronounced in the CD4+ T cell subset. Experimental depletion of CD4+ T cells in young BALB/c-TGF-β1−/− mice prevented the subsequent development of necroinflammatory liver disease, indicating that CD4+ T cells are essential for disease pathogenesis in vivo. These data definitively establish an immune-mediated etiology for necroinflammatory liver disease in BALB/c-TGF-β1−/− mice and demonstrate the importance of CD4+ T cells in disease pathogenesis in vivo. Furthermore, TGF-β1 has a critical role in homeostatic regulation of the hepatic immune system, inhibiting the development or expansion of hepatic cytolytic CD4+ T cells.

Object. The authors analyzed their series of carotid endarterectomies (CEAs), which were performed after administration of either a general or regional anesthetic, to determine whether the choice of anesthetic affected patients' clinical outcomes and length of hospital stay.Methods. A series of 803 consecutive CEAs performed between July 1990 and February 1999 was reviewed. Cases were analyzed for patient demographics, comorbid medical states, and perioperative complications. Contingency-table statistical analysis was used to compare the incidence of comorbid medical states and perioperative complications between patients who underwent CEA in which either a regional or general anesthetic was used. Student's t-test was used to compare the length of hospital stay and mean patient age.A regional anesthetic was used for 632 CEAs, and a general anesthetic was used for 171 operations. There were no statistically significant intergroup differences in demographics or comorbid medical states. The incidence of perioperative stroke and death did not differ significantly between the regional (2.7%) and the general anesthetic groups (2.3%). However, the incidence of nonneurological, nonfatal complications was significantly less in the regional anesthetic (1.6%) than in the general anesthetic group (14 .6%, p < 0.0001). Patients undergoing CEA in which a regional anesthetic was used had a significantly lower incidence of cardiopulmonary complications (myocardial infarction and postoperative intubation), cervical complications (neck hematomas and cranial nerve injuries), and urological complications (urinary retention) than patients who underwent surgery after receiving a general anesthetic.Conclusions. Patients undergoing CEA in which a regional anesthetic was used had significantly fewer nonneurological, nonfatal complications, particularly cardiopulmonary complications, than similar patients surgically treated after induction of general anesthesia.

A model compound, 4-(t-butyl)phenol, was used as a substitute for BPA (bisphenol acetone or Bisphenol A) a material used for the production of a large volume of common plastics. Unfortunately, BPA is suspected to have estrogenic properties, and there is a suspicion that even small amounts can have a deleterious effect against humans, especially female infants. The model compound has some similarities to BPA, but lacks some of the serious properties of BPA dust. Since other workers have demonstrated the capability of removing BPA from plastics by extraction with saline or alcohol, we studied whether Octolig, a polyethylenediimine supported on silica gel, or transition metal derivatives of Octolig could be used to remove concentrations for model compounds from aqueous solution. Octolig gave modest results 20%, the manganese (II) and iron (III) derivatives gave poor results, Cuprilig was an improvement over those two Metalloligs, but the cobalt(II) derivative was able to remove up to 56% of the model compound. Two methods were studied, batch and column chromatography. Under the conditions used in this study, the batch method was superior.