Circularly polarized blue fluorescence based on chiral heteroleptic six-coordinate bis-pyrazolonate-Zn2+ complexes.

Applying molecular design to chiral organo-Zn2+ complexes, a new pair of chiral heteroleptic bis-pyrazolonate-Zn2+ enantiomers [Zn(PMBP)2(1R,2R-Chxn)] (R,R-Zn2+; HPMBP = 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and 1R,2R-Chxn = (1R,2R)-cyclohexane-1,2-diamine) and [Zn(PMBP)2(1S,2S-Chxn)] (S,S-Zn2+; 1S,2S-Chxn = (1S,2S)-cyclohexane-1,2-diamine) have been synthesized and characterized in terms of photophysical and thermodynamic properties. In addition to a small Flack parameter (0.05(3)) associated with the solid-state elucidation of S,S-Zn2+, the circular dichroism (CD) and circularly polarized light (CPL) spectra for the chiral Zn2+ enantiomers show perfect mirror symmetry, establishing that the enantiopure 1,2-diamines successfully induce the optical isomerism of R,R-Zn2+ and S,S-Zn2+. As a result of the combined strong chiral induction capability of chiral 1,2-diamines and excellent photophysical properties of the pyrazolone ligand (PMBP)-, the two Zn2+ enantiomers exhibit high-quality pure blue fluorescence (ΦPL = 9-10%) and significant CPL activity (|glum| = 0.0065-0.0068). The heteroleptic strategy adopted in this study offers a new route to develop high-performance chiroptical luminophores.

Magnetic Interactions in a [Co(II)3Er(III)(OR)4] Model Cubane through Forefront Multiconfigurational Methods.

Strong electron correlation effects are one of the major challenges in modern quantum chemistry. Polynuclear transition metal clusters are peculiar examples of systems featuring such forms of electron correlation. Multireference strategies, often based on but not limited to the concept of complete active space, are adopted to accurately account for strong electron correlation and to resolve their complex electronic structures. However, transition metal clusters already containing four magnetic centers with multiple unpaired electrons make conventional active space based strategies prohibitively expensive, due to their unfavorable scaling with the size of the active space. In this work, forefront techniques, such as density matrix renormalization group (DMRG), full configuration interaction quantum Monte Carlo (FCIQMC), and multiconfiguration pair-density functional theory (MCPDFT), are employed to overcome the computational limitation of conventional multireference approaches and to accurately investigate the magnetic interactions taking place in a [Co(II)3Er(III)(OR)4] (chemical formula [Co(II)3Er(III)(hmp)4(µ2-OAc)2(OH)3(H2O)], hmp = 2-(hydroxymethyl)-pyridine) model cubane water oxidation catalyst. Complete active spaces with up to 56 electrons in 56 orbitals have been constructed for the seven energetically lowest different spin states. Relative energies, local spin, and spin-spin correlation values are reported and provide crucial insights on the spin interactions for this model system, pivotal in the rationalization of the catalytic activity of this system in the water-splitting reaction. A ferromagnetic ground state is found with a very small, ∼50 cm-1, highest-to-lowest spin gap. Moreover, for the energetically lowest states, S = 3-6, the three Co(II) sites exhibit parallel aligned spins, and for the lower states, S = 0-2, two Co(II) sites retain strong parallel spin alignment.

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry.

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations.

Resolution of Electronic States in Heisenberg Cluster Models within the Unitary Group Approach.

In this work ground and excited electronic states of Heisenberg cluster models, in the form of configuration interaction many-body wave functions, are characterized within the spin-adapted Graphical Unitary Group Approach framework, and relying on a novel combined unitary and symmetric group approach. Finite-size cluster models of well-defined point-group symmetry and of general local-spin Slocal>12 are presented, including J1-J2 triangular and tetrahedral clusters, which are often used to describe magnetic interactions in biological and biomimetic polynuclear transition metal clusters with unique catalytic activity, such as nitrogen fixation and photosynthesis. We show that a unique block-diagonal structure of the underlying Hamiltonian matrix in the spin-adapted basis emerges when an optimal lattice site ordering is chosen that reflects the internal symmetries of the model investigated. The block-diagonal structure is bound to the commutation relations between cumulative spin operators and the Hamiltonian operator, that in turn depend on the geometry of the cluster investigated. The many-body basis transformation, in the form of the orbital/site reordering, exposes such commutation relations. These commutation relations represent a rigorous and formal demonstration of the block-diagonal structure in Hamiltonian matrices and the compression of the corresponding spin-adapted many-body wave functions. As a direct consequence of the block-diagonal structure of the Hamiltonian matrix, it is possible to selectively optimize electronic excited states without the overhead of calculating the lower-energy states by simply relying on the initial ansatz for the targeted wave function. Additionally, more compact many-body wave functions are obtained. In extreme cases, electronic states are precisely described by a single configuration state function, despite the curse of dimensionality of the corresponding Hilbert space. These findings are crucial in the electronic structure theory framework, for they offer a conceptual route toward wave functions of reduced multireference character, that can be optimized more easily by approximated eigensolvers and are of more facile physical interpretation. They open the way to study larger ab initio and model Hamiltonians of increasingly larger number of correlated electrons, while keeping the computational costs at their lowest. In particular, these elements will expand the potential of electronic structure methods in understanding magnetic interactions in exchange-coupled polynuclear transition metal clusters.

Gamma-Glutamyl Transpeptidase-to-Platelet ratio predicts liver fibrosis in patients with concomitant chronic hepatitis B and nonalcoholic fatty liver disease.

OBJECTIVES: The aim of this study was to compare the correlation of gamma-glutamyl transpeptidase-to-platelet ratio (GPR), aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis index-4 (FIB-4), and liver stiffness measurement (LSM) in the diagnosis of liver fibrosis, and perform a diagnostic value of GPR for predicting fibrosis in CHB patients with NAFLD. METHODS: A retrospective study was conducted on CHB patients concurrent with NAFLD between September 2019 and December 2020. They were divided into control group (LSM ≤ 9.7 kpa) and fibrosis group (LSM ≥ 9.8 kpa). Demographic data were collected; ALT, AST, and PLT were also detected. LSM was measured by transient elastography (TE). The GPR, APRI, and FIB-4 were calculated. The correlation between GPR, APRI, FIB-4, and LSM was compared. The accuracy of predicting liver fibrosis using GPR, APRI, and FIB-4 was assessed. RESULTS: Eighty-five CHB patients with NAFLD were enrolled. Multivariate analysis showed that age (p = 0.005), GGT (p = 0.001), and PLT (p = 0.013) were the independent risk factors for LSM. The GPR (p = 0.008), APRI (p = 0.001), and FIB-4 (p = 0.001) values in fibrosis group were higher than control group. Pearson linear correlation was used to analyze the correlations between LSM and GPR, APRI, and FIB-4. LSM was correlated with GPR, APRI, and FIB-4. The AUCs of GPR, APRI, and FIB4 were 0.805, 0.766, and 0.826 in assessing liver fibrosis, respectively. No significant differences in the areas of GPR were comparable to that of APRI and FIB-4. CONCLUSION: GPR has a good correlation with LSM in assessing liver fibrosis and can be used as a noninvasive index for the assessment of liver fibrosis in patients with concomitant CHB and NAFLD.

Porosity Tunable Poly(Lactic Acid)-Based Composite Gel Polymer Electrolyte with High Electrolyte Uptake for Quasi-Solid-State Supercapacitors.

The growing popularity of quasi-solid-state supercapacitors inevitably leads to the unrestricted consumption of commonly used petroleum-derived polymer electrolytes, causing excessive carbon emissions and resulting in global warming. Also, the porosity and liquid electrolyte uptake of existing polymer membranes are insufficient for well-performed supercapacitors under high current and long cycles. To address these issues, poly(lactic acid) (PLA), a widely applied polymers in biodegradable plastics is employed to fabricate a renewable biocomposite membrane with tunable pores with the help of non-solvent phase inversion method, and a small amount of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is introduced as a modifier to interconnect with PLA skeleton for stabilizing the porous structure and optimizing the aperture of the membrane. Owing to easy film-forming and tunable non-solvent ratio, the porous membrane possesses high porosity (ca. 71%), liquid electrolyte uptake (366%), and preferable flexibility endowing the GPE with satisfactory electrochemical stability in coin and flexible supercapacitors after long cycles. This work effectively relieves the environmental stress resulted from undegradable polymers and reveals the promising potential and prospects of the environmentally friendly membrane in the application of wearable devices.

Synergistically reinforced poly(ethylene oxide)-based composite electrolyte for high-temperature lithium metal batteries.

Traditional liquid lithium-ion batteries are not applicable for extreme temperatures, due to the shrinkage of separators and volatility of electrolytes. It is necessary to develop advanced electrolytes with desirable characteristics in terms of thermal stability, electrochemical stability and mechanical properties. Solid-state electrolytes, such as polyethylene oxide (PEO), outperform other types and bring the opportunity to realize the high-temperature lithium-ion batteries. However, the softness of PEO at elevated temperatures leads to battery failure. In this work, a three-dimensional fiber-network-reinforced PEO-based composite polymer electrolyte is prepared. The introduced polyimide (PI) framework and trimethyl phosphate (TMP) plasticizer decrease the crystallinity of PEO and increase the ionic conductivity at 30 °C from 8.79 × 10-6 S cm-1 to 4.70 × 10-5 S cm-1. In addition, the PEO bonds tightly with PI fiber network, improving both the mechanical strength and thermal stability of the prepared electrolyte. With the above strategies, the working temperature range of the PEO-based electrolytes is greatly expanded. The LiFePO4/Li cell assembled with the PI-PEO-TMP electrolyte stably performs over 300 cycles at 120 °C. Even at 140 °C, the cell still survives 80 cycles. These excellent performances demonstrate the potential application of the PI-PEO-TMP electrolyte in developing safe and high-temperature lithium batteries.

FCIQMC-Tailored Distinguishable Cluster Approach: Open-Shell Systems.

A recently proposed tailored approach based on the distinguishable cluster method and the stochastic FCI solver, FCIQMC [J. Chem. Theory Comput. 2020, 16, 5621], is extended to open-shell molecular systems. The method is employed to calculate spin gaps of various Fe(II) complexes, including a Fe(II) porphyrin model system. Both distinguishable cluster and fully relaxed CASSCF natural orbitals were used in this work as reference for the subsequent tailored distinguishable cluster calculations. The distinguishable cluster natural orbitals occupation numbers were also used as an aid to the selection of the active space. The effect of the active space sizes and of the explicit correlation correction (F12) onto the predicted spin gaps is investigated. The tailored distinguishable cluster with singles and doubles yields consistently more accurate results compared to the tailored coupled cluster with singles and doubles.

Spin Purification in Full-CI Quantum Monte Carlo via a First-Order Penalty Approach.

In this article, we demonstrate that a first-order spin penalty scheme can be efficiently applied to the Slater determinant based Full-CI Quantum Monte Carlo (FCIQMC) algorithm, as a practical route toward spin purification. Two crucial applications are presented to demonstrate the validity and robustness of this scheme: the 1Δg ← 3Σg vertical excitation in O2 and key spin gaps in a [Mn3(IV)O4] cluster. In the absence of a robust spin adaptation/purification technique, both applications would be unattainable by Slater determinant based ground state methods, with any starting wave function collapsing into the higher-spin ground state during the optimization. This strategy can be coupled to other algorithms that use the Slater determinant based FCIQMC algorithm as configuration interaction eigensolver, including the Stochastic Generalized Active Space, the similarity-transformed FCIQMC, the tailored-CC, and second-order perturbation theory approaches. Moreover, in contrast to the GUGA-FCIQMC technique, this strategy features both spin projection and total spin adaptation, making it appealing when solving anisotropic Hamiltonians. It also provides spin-resolved reduced density matrices, important for the investigation of spin-dependent properties in polynuclear transition metal clusters, such as the hyperfine-coupling constants.

Digital vs. conventional workflow for one-abutment one-time immediate restoration in the esthetic zone: a randomized controlled trial.

OBJECTIVES: To compare short-term outcomes after immediate restoration of a single implant in the esthetic zone with one-abutment one-time technique comparing a conventional (control) vs. a fully digital workflow (test). MATERIALS AND METHODS: Eighteen subjects were randomly assigned to the two groups, and a digital implant planning was performed for all. In the test group, a custom-made zirconia abutment and a CAD-CAM provisional crown were prepared prior to surgery; implants were placed using a s-CAIS guide allowing immediate restoration after surgery. In the control group, the implant was placed free-handed using a conventional surgical guide, and a custom-made zirconia abutment to support a stratified provisional crown was placed 10 days thereafter, based on a conventional impression. Implant accuracy (relative to the planning), the provisional restoration outcomes, as well as PROMs were assessed. RESULTS: The implant positioning showed higher accuracy with the s-CAIS surgical guide compared to free-handed surgery (angular deviation (AD): 2.41 ± 1.27° vs. 6.26 ± 3.98°, p < 0.014; entry point deviation (CGD): 0.65 ± 0.37 mm vs. 1.27 ± 0.83 mm, p < 0.059; apical deviation (GAD): 1.36 ± 0.53 mm vs. 2.42 ± 1.02 mm, p < 0.014). The occlusion and interproximal contacts showed similar results for the two workflows (p = 0.7 and p = 0.69, respectively). The PROMs results were similar in both groups except for impression taking with intra-oral scanning preferred over conventional impressions (p = 0.014). CONCLUSIONS: Both workflows allowed implant placement and immediate/early restoration and displayed similar clinical and esthetic outcomes. The fully digital workflow was associated with a more accurate implant position relative to planning. CLINICAL RELEVANCE: Our results show that both conventional and digital workflow are predictive and provide similar clinical outcomes, with extra precision provided by digitalisation.

Supramolecular-induced 2.40 V 130 °C working-temperature-range supercapacitor aqueous electrolyte of lithium bis(trifluoromethanesulfonyl) imide in dimethyl sulfoxide-water.

Increasing the electrochemical stability window and working temperature range of supercapacitor aqueous electrolyte is the major task in order to advance aqueous electrolyte-based supercapacitors. Here, a supramolecular induced new electrolyte of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) in dimethyl sulfoxide (DMSO) and water co-solvent system is proposed. Adjusting the coordination structure among LiTFSI, DMSO, and water in the electrolyte via supramolecular interactions results in its high ionic conductivity, low viscosity, wide electrochemical stability window, and large working temperature range. The new electrolyte-based supercapacitors can work in 2.40 V working potential and 130 °C working-temperature range from -40 to 90 °C. The devices exhibit good electrochemical performances, especially the energy density over 21 Wh kg-1, which is much higher than that with traditional aqueous electrolytes (<10 Wh kg-1). The work paves a way to develop high-performance aqueous electrolytes for supercapacitors.

Stochastic Generalized Active Space Self-Consistent Field: Theory and Application.

An algorithm to perform stochastic generalized active space calculations, Stochastic-GAS, is presented, that uses the Slater determinant based FCIQMC algorithm as configuration interaction eigensolver. Stochastic-GAS allows the construction and stochastic optimization of preselected truncated configuration interaction wave functions, either to reduce the computational costs of large active space wave function optimizations, or to probe the role of specific electron correlation pathways. As for the conventional GAS procedure, the preselection of the truncated wave function is based on the selection of multiple active subspaces while imposing restrictions on the interspace excitations. Both local and cumulative minimum and maximum occupation number constraints are supported by Stochastic-GAS. The occupation number constraints are efficiently encoded in precomputed probability distributions, using the precomputed heat bath algorithm, which removes nearly all runtime overhead of GAS. This strategy effectively allows the FCIQMC dynamics to a priori exclude electronic configurations that are not allowed by GAS restrictions. Stochastic-GAS reduced density matrices are stochastically sampled, allowing orbital relaxations via Stochastic-GASSCF, and direct evaluation of properties that can be extracted from density matrices, such as the spin expectation value. Three test case applications have been chosen to demonstrate the flexibility of Stochastic-GAS: (a) the Stochastic-GASSCF [5·(6, 6)] optimization of a stack of five benzene molecules, that shows the applicability of Stochastic-GAS toward fragment-based chemical systems; (b) an uncontracted stochastic MRCISD calculation that correlates 96 electrons and 159 molecular orbitals, and uses a large (32, 34) active space reference wave function for an Fe(II)-porphyrin model system, showing how GAS can be applied to systematically recover dynamic electron correlation, and how in the specific case of the Fe(II)-porphyrin dynamic correlation further differentially stabilizes the 3Eg over the 5A1g spin state; (c) the study of an Fe4S4 cluster's spin-ladder energetics via highly truncated stochastic-GAS [4·(5, 5)] wave functions, where we show how GAS can be applied to understand the competing spin-exchange and charge-transfer correlating mechanisms in stabilizing different spin-states.

Spin-Pure Stochastic-CASSCF via GUGA-FCIQMC Applied to Iron-Sulfur Clusters.

In this work, we demonstrate how to efficiently compute the one- and two-body reduced density matrices within the spin-adapted full configuration interaction quantum Monte Carlo (FCIQMC) method, which is based on the graphical unitary group approach (GUGA). This allows us to use GUGA-FCIQMC as a spin-pure configuration interaction (CI) eigensolver within the complete active space self-consistent field (CASSCF) procedure and hence to stochastically treat active spaces far larger than conventional CI solvers while variationally relaxing orbitals for specific spin-pure states. We apply the method to investigate the spin ladder in iron-sulfur dimer and tetramer model systems. We demonstrate the importance of the orbital relaxation by comparing the Heisenberg model magnetic coupling parameters from the CASSCF procedure to those from a CI-only (CASCI) procedure based on restricted open-shell Hartree-Fock orbitals. We show that the orbital relaxation differentially stabilizes the lower-spin states, thus enlarging the coupling parameters with respect to the values predicted by ignoring orbital relaxation effects. Moreover, we find that, while CASCI results are well fit by a simple bilinear Heisenberg Hamiltonian, the CASSCF eigenvalues exhibit deviations that necessitate the inclusion of biquadratic terms in the model Hamiltonian.

Modeling magnetic interactions in high-valent trinuclear [Mn3(IV)O4]4+ complexes through highly compressed multi-configurational wave functions.

In this work we apply a quantum chemical framework, recently designed in our laboratories, to rationalize the low-energy electronic spectrum and the magnetic properties of an homo-valent trinuclear [Mn3(IV)O4]4+ model of the oxygen-evolving center in photosystem II. The method is based on chemically motivated molecular orbital unitary transformations, and the optimization of spin-adapted many-body wave functions, both for ground- and excited-states, in the transformed MO basis. In this basis, the configuration interaction Hamiltonian matrix of exchange-coupled multi-center clusters is extremely sparse and characterized by a unique block diagonal structure. This property leads to highly compressed wave functions (oligo- or single-reference) and crucially enables state-specific optimizations. This work is the first showing that compression and selective targeting of ground- and excited-states wave functions is possible for systems with three magnetic centers that are not exactly half-filled, and that potentially exhibit frustrated spin interactions. The reduced multi-reference character of the wave function greatly simplifies the interpretation of the ground- and excited-state electronic structures, and provides a route for the direct rationalization of magnetic interactions in these compounds, often considered a challenge in polynuclear transition-metal chemistry. In this study, strong electron correlation effects have explicitly been described by conventional and stochastic multiconfigurational methodologies, while dynamic correlation effects have been accounted for by multiconfigurational second order perturbation theory, CASPT2. Ab initio results for the [Mn3(IV)O4]4+ system have been mapped to a three-site Heisenberg model with two magnetic coupling constants. The magnetic coupling constants and the temperature dependence of the effective magnetic moment predicted by the ab initio calculations are in good agreement with the available experimental data, and confirm the antiferromagnetic interaction among the three magnetic centers, while providing a simple and rigorous description of the noncollinearity of the local spins, that characterize most of the low-energy states for this system.

Quenched Lewis Acidity: Studies on the Medium Dependent Fluorescence of Zinc(II) Complexes.

Three new zinc(II) coordination units [Zn(1-3)] based on planar-directing tetradentate Schiff base-like ligands H2 (1-3) were synthesized. Their solid-state structures were investigated by single crystal X-ray diffraction, showing the tendency to overcome the square-planar coordination sphere by axial ligation. Affinity in solution towards axial ligation has been tested by extended spectroscopic studies, both in the absorption and emission mode. The electronic spectrum of the pyridine complex [Zn(1)(py)] has been characterized by MC-PDFT to validate the results of extended TD-DFT studies. Green emission of non-emissive solutions of [Zn(1-3)] in chloroform could be switched on in the presence of potent Lewis-bases. While interpretation in terms of an equilibrium of stacked/non-fluorescent and destacked/fluorescent species is in line with precedents from literature, the sensitivity of [Zn(1-3)] was greatly reduced. Results of a computation-based structure search allow to trace the hidden Lewis acidity of [Zn(1-3)] to a new stacking motif, resulting in a strongly enhanced stability of the dimers.

Resolution of Low-Energy States in Spin-Exchange Transition-Metal Clusters: Case Study of Singlet States in [Fe(III)4S4] Cubanes.

Polynuclear transition-metal (PNTM) clusters owe their catalytic activity to numerous energetically low-lying spin states and stable oxidation states. The characterization of their electronic structure represents one of the greatest challenges of modern chemistry. We propose a theoretical framework that enables the resolution of targeted electronic states with ease and apply it to two [Fe(III)4S4] cubanes. Through direct access to their many-body wave functions, we identify important correlation mechanisms and their interplay with the geometrical distortions observed in these clusters, which are core properties in understanding their catalytic activity. The simulated magnetic coupling constants predicted by our strategy allow us to make qualitative connections between spin interactions and geometrical distortions, demonstrating its predictive power. Moreover, despite its simplicity, the strategy provides magnetic coupling constants in good agreement with the available experimental ones. The complexes are intrinsically frustrated anti-ferromagnets, and the obtained spin structures together with the geometrical distortions represent two possible ways to release spin frustration (spin-driven Jahn-Teller distortion). Our paradigm provides a simple, yet rigorous, route to uncover the electronic structure of PNTM clusters and may be applied to a wide variety of such clusters.

Antimony nanocrystals self-encapsulated within bio-oil derived carbon for ultra-stable sodium storage.

Integrating carbon-coating and nanostructuring has been considered as the most promising strategy to accommodate the dramatic volume expansion represented by high-capacity antimony (Sb) upon sodiation. Suitable coating source and synthetic strategy that are both economical and strong are yet to be explored. In this regard, by using renewable bio-oil as carbon source and self-wrapping precursor, robust Sb@C composite anode with Sb nanoparticles homogeneously impregnated into the cross-linked 2D ultrathin carbon nanosheets is developed via a facile NaCl template-assisted self-assembly and followed carbothermal reduction method. Such judiciously crafted interconnected macroporous framework can mitigate of mechanical stress and alleviate the volume change of inner Sb, guaranteeing high-performance sodium-ion battery anode. At a current density of 0.1 A g-1, ultrahigh reversible capacity of 520 mAh g-1 can be achieved. Notably, a stable capacity of 391 mAh g-1 is even retained after 500 cycles at 1 A g-1. Such a facile and cost-effective synthetic method is promising for high-performance sodium-ion batteries.

Clinical and radiographic assessment of circular versus triangular cross-section neck Implants in the posterior maxilla: A 1-year randomized controlled trial.

OBJECTIVES: Implants with a triangular neck were recently introduced to limit peri-implant bone loss. The primary objective of this randomized controlled trial was to compare peri-implant bone changes of circular versus triangular cross-section neck implants 1 year after loading. The secondary objectives were to assess buccal hard tissue thickness changes, Pink Esthetic Score (PES), and patient satisfaction. MATERIAL AND METHODS: Thirty four patients requiring replacement of the single, intercalated missing tooth of healed site for at least 4 months in the posterior maxilla were randomized into 2 groups according to the type of implant. Immediately after surgery and 1 year after final restoration, a cone beam CT (CBCT) was performed to assess proximal bone remodeling and buccal bone thickness. Peri-implant soft tissue health, PES, and patient-reported outcome measures (PROMs) were recorded. RESULTS: No implant loss occurred within the follow-up period. The mean ± SD peri-implant proximal bone loss 1 year after loading was 0.22 ± 0.30 mm for triangular and 0.42 ± 0.67 mm for circular implants necks (p = .25). Peri-implant bone loss exceeding 2 mm was observed in a single implant in the circular neck group. Buccal bone thickness remained stable and did not differ different between the 2 groups. The peri-implant soft tissue health, PES, and patient satisfaction were also comparable. CONCLUSIONS: Within the limitations of the present study, patient clinical and radiographic outcomes did not differ between triangular and circular cross-section neck implants in the posterior maxilla.

Compression of Spin-Adapted Multiconfigurational Wave Functions in Exchange-Coupled Polynuclear Spin Systems.

We present a protocol based on unitary transformations of molecular orbitals to reduce the number of nonvanishing coefficients of spin-adapted configuration interaction expansions. Methods that exploit the sparsity of the Hamiltonian matrix and compactness of its eigensolutions, such as the full configuration interaction quantum Monte Carlo (FCIQMC) algorithm in its spin-adapted implementation, are well suited to this protocol. The wave function compression resulting from this approach is particularly attractive for antiferromagnetically coupled polynuclear spin systems, such as transition-metal cubanes in biocatalysis, and Mott and charge-transfer insulators in solid-state physics. Active space configuration interaction calculations on N2 and CN- at various bond lengths, the stretched square N4 compounds, the chromium dimer, and a [Fe2S2]2- model system are presented as a proof-of-concept. For the Cr2 case, large and intermediate bond distances are discussed, showing that the approach is effective in cases where static and dynamic correlations are equally important. The [Fe2S2]2- case shows the general applicability of the method.

Novel Polyimide Separator Prepared with Two Porogens for Safe Lithium-Ion Batteries.

A porous polyimide (PI) membrane is successfully prepared via nonsolvent-induced phase separation with two porogens: dibutyl phthalate and glycerin. The as-prepared uniform porous PI membrane shows excellent separator properties for lithium-ion batteries (LIBs). Compared with the commercial polyethylene (PE) separator, the PI separator exhibits significant thermal stability, better ionic conductivity, and wettability both in carbonate and ether electrolytes for LIBs. The battery coin-cells assembled with the PI separator is more robust and still works even after heating at 140 °C for 1 h, while the cells with the commercial PE separator could not charge any more due to the shrinkage of the PE under the same condition.