Acquired Human Immunodeficiency Virus Type 1 Drug Resistance in Rhode Island, USA, 2004-2021.

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) acquired drug resistance (ADR) compromises antiretroviral therapy (ART). METHODS: We aggregated all HIV-1 protease-reverse transcriptase-integrase sequences over 2004-2021 at the largest HIV center in Rhode Island and evaluated ADR extent, trends, and impact using Stanford Database tools. Trends were measured with Mann-Kendall statistic, and multivariable regressions evaluated resistance predictors. RESULTS: Sequences were available for 914 ART-experienced persons. Overall ADR to any drug decreased from 77% to 49% (-0.66 Mann-Kendall statistic); nucleoside reverse transcriptase inhibitors 65% to 32%, nonnucleoside reverse transcriptase inhibitors 53% to 43%, and protease inhibitors 28% to 7% (2004-2021), and integrase strand transfer inhibitors 16% to 13% (2017-2021). Multiclass resistance decreased from 44% to 12% (2-class) and 12% to 6% (3-class). In 2021, 94% had at least one 3-drug or 2-drug one-pill-once-daily (OPOD) option. Males and those exposed to more ART regimens were more likely to have ≥2-class resistance, and higher regimen exposure was also associated with fewer OPOD options. CONCLUSIONS: Comprehensive analyses within a densely-sampled HIV epidemic over 2004-2021 demonstrated decreasing ADR. Continued ADR monitoring is important to maintain ART success, particularly with rising INSTI use in all lines of therapy and 2-drug and long-acting formulations.

Speciation and Reactivity Control of Cu-Oxo Clusters via Extraframework Al in Mordenite for Methane Oxidation.

The stoichiometric conversion of methane to methanol by Cu-exchanged zeolites can be brought to highest yields by the presence of extraframework Al and high CH4 chemical potentials. Combining theory and experiments, the differences in chemical reactivity of monometallic Cu-oxo and bimetallic Cu-Al-oxo nanoclusters stabilized in zeolite mordenite (MOR) are investigated. Cu-L3 edge X-ray absorption near-edge structure (XANES), infrared (IR), and ultraviolet-visible (UV-vis) spectroscopies, in combination with CH4 oxidation activity tests, support the presence of two types of active clusters in MOR and allow quantification of the relative proportions of each type in dependence of the Cu concentration. Ab initio molecular dynamics (MD) calculations and thermodynamic analyses indicate that the superior performance of materials enriched in Cu-Al-oxo clusters is related to the activity of two µ-oxo bridges in the cluster. Replacing H2O with ethanol in the product extraction step led to the formation of ethyl methyl ether, expanding this way the applicability of these materials for the activation and functionalization of CH4. We show that competition between different ion-exchanged metal-oxo structures during the synthesis of Cu-exchanged zeolites determines the formation of active species, and this provides guidelines for the synthesis of highly active materials for CH4 activation and functionalization.

Solution Structures of Europium Terpyridyl Complexes with Nitrate and Triflate Counterions in Acetonitrile.

Lanthanide-ligand complexes are key components of technological applications, and their properties depend on their structures in the solution phase, which are challenging to resolve experimentally or computationally. The coordination structure of the Eu3+ ion in different coordination environments in acetonitrile is examined using ab initio molecular dynamics (AIMD) simulations and extended X-ray absorption fine structure (EXAFS) spectroscopy. AIMD simulations are conducted for the solvated Eu3+ ion in acetonitrile, both with or without a terpyridyl ligand, and in the presence of either triflate or nitrate counterions. EXAFS spectra are calculated directly from AIMD simulations and then compared to experimentally measured EXAFS spectra. In acetonitrile solution, both nitrate and triflate anions are shown to coordinate directly to the Eu3+ ion forming either ten- or eight-coordinate solvent complexes where the counterions are binding as bidentate or monodentate structures, respectively. Coordination of a terpyridyl ligand to the Eu3+ ion limits the available binding sites for the solvent and anions. In certain cases, the terpyridyl ligand excludes any solvent binding and limits the number of coordinated anions. The solution structure of the Eu-terpyridyl complex with nitrate counterions is shown to have a similar arrangement of Eu3+ coordinating molecules as the crystal structure. This study illustrates how a combination of AIMD and EXAFS can be used to determine how ligands, solvent, and counterions coordinate with the lanthanide ions in solution.

The evolution of solvation symmetry and composition in Zn halide aqueous solutions from dilute to extreme concentrations.

The emergence of cation-anion species, or contact ion pairs, is fundamental to understanding the physical properties of aqueous solutions when moving from the ideal, low-concentration limit to the manifestly non-ideal limits of very high solute concentration or constituent ion activity. We focus here on Zn halide solutions both as a model system and also as an exemplar of the applications spanning from (i) electrical energy storage via the paradigm of water in salt electrolyte (WiSE) to (ii) the physical chemistry of brines in geochemistry to (iii) the long-standing problem of nucleation. Using a combination of experimental and theoretical approaches we quantify the halide coordination number and changing coordination geometry without embedded use of theoretical equilibrium constants. These results and the associated methods, notably including the use of valence-to-core X-ray emission spectroscopy, provide new insights into the Zn halide system and new research directions in the physical chemistry of concentrated electrolytes.

G0W0 Ionization Potentials of First-Row Transition Metal Aqua Ions.

We report computations of the vertical ionization potentials within the GW approximation of the near-complete series of first-row transition metal (V-Cu) aqua ions in their most common oxidation states, i.e., V3+, Cr3+, Cr2+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, and Cu2+. The d-orbital occupancy of these systems spans a broad range from d2 to d9. All of the structures were first optimized at the density functional theory level using a large cluster of explicit water molecules that are embedded in a continuum solvation model. Vertical ionization potentials were computed with the one-shot G0W0 approach on a range of transition metal ion clusters (6, 18, 40, and 60 explicit water molecules), wherein the convergence with respect to the basis set size was evaluated using the systems with 40 water molecules. We assess the results using three different density functional approximations as starting points for the vertical ionization potential calculations, namely, G0W0@PBE, G0W0@PBE0, and G0W0@r2SCAN. While the predicted ground-state structures are similar to all three exchange-correlation functionals, the vertical ionization potentials were in closer agreement with experiment when using the G0W0@PBE0 and G0W0@r2SCAN approaches, with the r2SCAN-based calculations being significantly less expensive. Computed bond distances and vertical ionization potentials for all structures are in good agreement with available experimental data.

Evaluation of real-time monitored ozone concentration from Abuja, Nigeria.

Real-time ozone (O3) concentration is vital for accurate analysis of O3 to inform the public about O3 concentrations that may have an adverse effect on health. Few studies have analysed air pollution in Abuja, Nigeria and non on real-time ozone concentrations. As a result, there is a scarcity of data and information on real-time ozone pollution, pointing to a gap that needs to be urgently closed to enable a better understanding of ozone pollution and the causes and consequences in terms of the associated health risks.In this study, -time concentrations of ground-level ozone were measured in a busy urban pollution monitoring station. Using a real-time ozone monitor to enable real-time monitoring of O3 concentration of ozone for the first time in Abuja. The ozone concentrations followed a clear pattern with high concentrations being recorded during the dry (harmattan) season. Concentrations higher than the WHO standard of (eight-hour averaged) 100 µg/m3, occurred on 53 days over the 5-month dry season. Of those 53 days, 18 had ozone concentrations greater than 200 µg/m3. Daily patterns showed a rise throughout the day, reaching a peak in the evening. Weekday/weekend differences were less pronounced than those found in other studies. High temperatures and local climatic conditions in Abuja encourage the formation of ozone. In this study, we confirm the concentration of ozone, and the pattern can be episodic and potentially damaging to health. There is a need for better regulation and measures to reduce ozone, particularly when local climatic conditions, such as harmattan, favour the development of photochemical smog in such settings.

Ionic Contraction across the Lanthanide Series Decreases the Temperature-Induced Disorder of the Water Coordination Sphere.

In liquid, temperature affects the structures of lanthanide complexes in multiple ways that depend upon complex interactions between ligands, anions, and solvent molecules. The relative simplicity of lanthanide aqua ions (Ln3+) make them well suited to determine how temperature induces structural changes in lanthanide complexes. We performed a combination of ab initio molecular dynamics (AIMD) simulations and extended X-ray absorption fine structure (EXAFS) measurements, both at 25 and 90 °C, to determine how temperature affects the first- and second-coordination spheres of three Ln3+ (Ce3+, Sm3+, and Lu3+) aqua ions. AIMD simulations show first lanthanide coordination spheres that are similar at 25 and 90 °C, more so for the Lu3+ ion that remains as eight-coordinate than for the Ce3+ and Sm3+ ions that change their preferred coordination number from nine (at 25 °C) to eight (at 90 °C). The measured EXAFS spectra are very similar at 25 and 90 °C, for the Ce3+, Sm3+, and Lu3+ ions, suggesting that the dynamical disorder of the Ln3+ ions in liquid water is sufficient such that temperature-induced changes do not clearly manifest changes in the structure of the three ions. Both AIMD simulations and EXAFS measurements show very similar structures of the first coordination sphere of the Lu3+ ion at 25 and 90 °C.

Water Defect Stabilizes the Bi3+ Lone-Pair Electronic State Leading to an Unusual Aqueous Hydration Structure.

The aqueous hydration structure of the Bi3+ ion is probed using a combination of extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) simulations of ion-water clusters and condensed-phase solutions. Anomalous features in the EXAFS spectra are found to be associated with a highly asymmetric first-solvent water shell. The aqueous chemistry and structure of the Bi3+ ion are dramatically controlled by the water stabilization of a lone-pair electronic state involving the mixed 6s and 6p orbitals. This leads to a distinct multimodal distribution of water molecules in the first shell that are separated by about 0.2 Å. The lone-pair structure is stabilized by a collective response of multiple waters that are localized near the lone-pair anti-bonding site. The findings indicate that the lone-pair stereochemistry of aqueous Bi3+ ions plays a major role in the binding of water and ligands in aqueous solutions.

Environment of Metal-O-Fe Bonds Enabling High Activity in CO2 Reduction on Single Metal Atoms and on Supported Nanoparticles.

Single-atom catalysts are often reported to have catalytic properties that surpass those of nanoparticles, while a direct comparison of sites common and different for both is lacking. Here we show that single atoms of Pt-group metals embedded into the surface of Fe3O4 have a greatly enhanced interaction strength with CO2 compared with the Fe3O4 surface. The strong CO2 adsorption on single Rh atoms and corresponding low activation energies lead to 2 orders of magnitude higher conversion rates of CO2 compared to Rh nanoparticles. This high activity of single atoms stems from the partially oxidic state imposed by their coordination to the support. Fe3O4-supported Rh nanoparticles follow the behavior of single atoms for CO2 interaction and reduction, which is attributed to the dominating role of partially oxidic sites at the Fe3O4-Rh interface. Thus, we show a likely common catalytic chemistry for two kinds of materials thought to be different, and we show that single atoms of Pt-group metals on Fe3O4 are especially successful materials for catalyzed reactions that depend primarily upon sites with the metal-O-Fe environment.

Coordination Sphere of Lanthanide Aqua Ions Resolved with Ab Initio Molecular Dynamics and X-ray Absorption Spectroscopy.

To resolve the fleeting structures of lanthanide Ln3+ aqua ions in solution, we (i) performed the first ab initio molecular dynamics (AIMD) simulations of the entire series of Ln3+ aqua ions in explicit water solvent using pseudopotentials and basis sets recently optimized for lanthanides and (ii) measured the symmetry of the hydrating waters about Ln3+ ions (Nd3+, Dy3+, Er3+, Lu3+) for the first time with extended X-ray absorption fine structure (EXAFS). EXAFS spectra were measured experimentally and generated from AIMD trajectories to directly compare simulation, which concurrently considers the electronic structure and the atomic dynamics in solution, with experiment. We performed a comprehensive evaluation of EXAFS multiple-scattering analysis (up to 6.5 Å) to measure Ln-O distances and angular correlations (i.e., symmetry) and elucidate the molecular geometry of the first hydration shell. This evaluation, in combination with symmetry-dependent L3- and L1-edge spectral analysis, shows that the AIMD simulations remarkably reproduces the experimental EXAFS data. The error in the predicted Ln-O distances is less than 0.07 Å for the later lanthanides, while we observed excellent agreement with predicted distances within experimental uncertainty for the early lanthanides. Our analysis revealed a dynamic, symmetrically disordered first coordination shell, which does not conform to a single molecular geometry for most lanthanides. This work sheds critical light on the highly elusive coordination geometry of the Ln3+ aqua ions.

Materials Engineering of Violin Soundboards by Stradivari and Guarneri.

We investigated the material properties of Cremonese soundboards using a wide range of spectroscopic, microscopic, and chemical techniques. We found similar types of spruce in Cremonese soundboards as in modern instruments, but Cremonese spruces exhibit unnatural elemental compositions and oxidation patterns that suggest artificial manipulation. Combining analytical data and historical information, we may deduce the minerals being added and their potential functions-borax and metal sulfates for fungal suppression, table salt for moisture control, alum for molecular crosslinking, and potash or quicklime for alkaline treatment. The overall purpose may have been wood preservation or acoustic tuning. Hemicellulose fragmentation and altered cellulose nanostructures are observed in heavily treated Stradivari specimens, which show diminished second-harmonic generation signals. Guarneri's practice of crosslinking wood fibers via aluminum coordination may also affect mechanical and acoustic properties. Our data suggest that old masters undertook materials engineering experiments to produce soundboards with unique properties.

57% decline in Rhode Island invasive breast cancer mortality between 1987 and 2017: mammography predominates in preventing mortality.

BACKGROUND: Controversy exists regarding proportional contributions of mammographic screening versus systemic therapy to declining disease-specific mortality of female invasive breast cancer (IBC) in the United States. Understanding relative contributions may help address allocation of medical resources. METHODS: A 31-year (1987-2017) review of Rhode Island (RI) Cancer Registry data of female IBC was carried out in a state with high rates of mammographic screening. RESULTS: Over 31 years in RI, statistically significant improvements occurred at initial diagnosis of IBC: mean and median maximum cancer diameters decreased by 21% and 30% respectively. Despite 1997 introduction of more accurate sentinel lymph node biopsy, the proportion of patients with axillary lymph node metastases (LNM) decreased by 27%. Extent of LNM also decreased as patients with over three node metastases decreased 67%. By 2017, 53% of all patients with LNM had only one. Poorly differentiated cancers decreased 50%. Disease-specific mortality decreased 57%. DISCUSSION: Improvements in initial presentation of IBC are consistent with most having progressive growth, from cellular origin to palpable mass, the currently accepted biological model. Breast cancers identified earlier at initial diagnosis through screening mammography are characterized by smaller size, fewer axillary LNMs, better grade differentiation, and decreased mortality. Statistical analysis from these improved diagnostic parameters indicate that the majority of mortality decline from invasive breast cancer in RI can be attributed to earlier detection. Thus, mammography predominates in preventing mortality.

Importance of Methane Chemical Potential for Its Conversion to Methanol on Cu-exchanged Mordenite.

Invited for the cover of this issue is the collaborative team of researchers from TU Munich, PNNL and TU Delft. Read the full text of the article at 10.1002/chem.202000772.

Importance of Methane Chemical Potential for Its Conversion to Methanol on Cu-Exchanged Mordenite.

Copper-oxo clusters exchanged in zeolite mordenite are active in the stoichiometric conversion of methane to methanol at low temperatures. Here, we show an unprecedented methanol yield per Cu of 0.6, with a 90-95 % selectivity, on a MOR solely containing [Cu3 (µ-O)3 ]2+ active sites. DFT calculations, spectroscopic characterization and kinetic analysis show that increasing the chemical potential of methane enables the utilization of two µ-oxo bridge oxygen out of the three available in the tricopper-oxo cluster structure. Methanol and methoxy groups are stabilized in parallel, leading to methanol desorption in the presence of water.

Quantifying the hydration structure of sodium and potassium ions: taking additional steps on Jacob's Ladder.

The ability to reproduce the experimental structure of water around the sodium and potassium ions is a key test of the quality of interaction potentials due to the central importance of these ions in a wide range of important phenomena. Here, we simulate the Na+ and K+ ions in bulk water using three density functional theory functionals: (1) the generalized gradient approximation (GGA) based dispersion corrected revised Perdew, Burke, and Ernzerhof functional (revPBE-D3) (2) the recently developed strongly constrained and appropriately normed (SCAN) functional (3) the random phase approximation (RPA) functional for potassium. We compare with experimental X-ray diffraction (XRD) and X-ray absorption fine structure (EXAFS) measurements to demonstrate that SCAN accurately reproduces key structural details of the hydration structure around the sodium and potassium cations, whereas revPBE-D3 fails to do so. However, we show that SCAN provides a worse description of pure water in comparison with revPBE-D3. RPA also shows an improvement for K+, but slow convergence prevents rigorous comparison. Finally, we analyse cluster energetics to show SCAN and RPA have smaller fluctuations of the mean error of ion-water cluster binding energies compared with revPBE-D3.

Selective Methane Oxidation to Methanol on Cu-Oxo Dimers Stabilized by Zirconia Nodes of an NU-1000 Metal-Organic Framework.

Mononuclear and dinuclear copper species were synthesized at the nodes of an NU-1000 metal-organic framework (MOF) via cation exchange and subsequent oxidation at 200 °C in oxygen. Copper-exchanged MOFs are active for selectively converting methane to methanol at 150-200 °C. At 150 °C and 1 bar methane, approximately a third of the copper centers are involved in converting methane to methanol. Methanol productivity increased by 3-4-fold and selectivity increased from 70% to 90% by increasing the methane pressure from 1 to 40 bar. Density functional theory showed that reaction pathways on various copper sites are able to convert methane to methanol, the copper oxyl sites with much lower free energies of activation. Combining studies of the stoichiometric activity with characterization by in situ X-ray absorption spectroscopy and density functional theory, we conclude that dehydrated dinuclear copper oxyl sites formed after activation at 200 °C are responsible for the activity.

Well-Defined Rhodium-Gallium Catalytic Sites in a Metal-Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-Alkenes.

Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-organic framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.

Sinter-Resistant Platinum Catalyst Supported by Metal-Organic Framework.

Single atoms and few-atom clusters of platinum are uniformly installed on the zirconia nodes of a metal-organic framework (MOF) NU-1000 via targeted vapor-phase synthesis. The catalytic Pt clusters, site-isolated by organic linkers, are shown to exhibit high catalytic activity for ethylene hydrogenation while exhibiting resistance to sintering up to 200 °C. In situ IR spectroscopy reveals the presence of both single atoms and few-atom clusters that depend upon synthesis conditions. Operando X-ray absorption spectroscopy and X-ray pair distribution analyses reveal unique changes in chemical bonding environment and cluster size stability while on stream. Density functional theory calculations elucidate a favorable reaction pathway for ethylene hydrogenation with the novel catalyst. These results provide evidence that atomic layer deposition (ALD) in MOFs is a versatile approach to the rational synthesis of size-selected clusters, including noble metals, on a high surface area support.

Methane Oxidation to Methanol Catalyzed by Cu-Oxo Clusters Stabilized in NU-1000 Metal-Organic Framework.

Copper oxide clusters synthesized via atomic layer deposition on the nodes of the metal-organic framework (MOF) NU-1000 are active for oxidation of methane to methanol under mild reaction conditions. Analysis of chemical reactivity, in situ X-ray absorption spectroscopy, and density functional theory calculations are used to determine structure/activity relations in the Cu-NU-1000 catalytic system. The Cu-loaded MOF contained Cu-oxo clusters of a few Cu atoms. The Cu was present under ambient conditions as a mixture of ∼15% Cu+ and ∼85% Cu2+. The oxidation of methane on Cu-NU-1000 was accompanied by the reduction of 9% of the Cu in the catalyst from Cu2+ to Cu+. The products, methanol, dimethyl ether, and CO2, were desorbed with the passage of 10% water/He at 135 °C, giving a carbon selectivity for methane to methanol of 45-60%. Cu oxo clusters stabilized in NU-1000 provide an active, first generation MOF-based, selective methane oxidation catalyst.