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We study several approaches to orbital optimization in selected configuration interaction (SCI) plus perturbation theory methods and test them on the ground and excited states of three molecules using the semistochastic heat-bath configuration interaction method. We discuss the ways in which the orbital optimization problem in SCI resembles and differs from that in complete active space self-consistent field. Starting from natural orbitals, these approaches divide into three classes of optimization methods according to how they treat coupling between configuration interaction coefficients and orbital parameters, namely uncoupled, fully coupled, and quasi-fully coupled methods. We demonstrate that taking the coupling into account is crucial for fast convergence and recommend two quasi-fully coupled methods for such applications accelerated diagonal Newton and Broyden-Fletcher-Goldfarb-Shanno.Nitrates formed on mineral dust through heterogeneous reactions in high NOx areas can undergo photolysis to regenerate NOx and potentially interfere in the photochemistry in the downwind low NOx areas. However, little is known about such renoxification processes. In this study, photolysis of various nitrates on different mineral oxides was comprehensively investigated in a flow reactor and in situ diffuse reflectance Fourier-transform infrared spectroscopy (in situ DRIFTS). TiO2 was found much more reactive than Al2O3 and SiO2 with both NO2 and HONO as the two major photolysis products. The yields of NO2 and HONO depend on the cation basicity of the nitrate salts or the acidity of particles. As such, NH4NO3 is much more productive than other nitrates like Fe(NO3)3, Ca(NO3)2, and KNO3. SO2 and water vapor promote the photodegradation by increasing the surface acidity due to the photoinduced formation of H2SO4/sulfate and H+, respectively. O2 enables the photo-oxidation of NOx to regenerate nitrate and thus inhibits the NOx yield. Overall, our results demonstrated that the photolysis of nitrate can be accelerated under complex air pollution conditions, which are helpful for understanding the transformation of nitrate and the nitrogen cycle in the atmosphere.Antiphagocytic capsular polysaccharides are key components of effective vaccines against pathogenic bacteria. Neisseria meningitidis groups B and C, as well as Escherichia coli serogroups K1 and K92, are coated with polysialic acid capsules. Although the chemical structure of these polysaccharides and the organization of the associated gene clusters have been described for many years, only recently have the details of the biosynthetic pathways been discovered. The polysialic acid chains are synthesized by polysialyltransferases on a proposed phosphatidylglycerol lipid acceptor with a poly keto-deoxyoctulosonate (KDO) linker. Synthesis of this acceptor requires at least three enzymes in E. coli K1 KpsS, KpsC, and NeuE. In this report, we have characterized the β-KDO glycosyltransferase KpsS, the first enzyme in the pathway for lipid acceptor synthesis. After purification of KpsS in a soluble active form, we investigated its function and substrate specificity and showed that KpsS can transfer a KDO residue to a fluorescently labeled phosphatidylglycerol lipid. The enzyme tolerated various lengths of fatty acid acyl chains on the phosphatidylglycerol, including fluorescent tags, but exhibited a preference for phosphatidylglycerol diacylated with longer fatty acid chains as indicated by the smaller Kd and Km values for substrates with chains with more than 14 members. Additional structural analysis of the KpsS product confirmed that KpsS transfers KDO from CMP-KDO to the 1-hydroxyl of phosphatidylglycerol to form a β-KDO linkage.Birefringence, an important optical performance parameter for optoelectronic functional materials, is mainly influenced by the types of anion groups and their spatial arrangement. Inspired by the relationship between the structure and properties of chalcogenides, combined with the dimensional transformation, we successfully synthesized a sulfide compound (Cs2ZnSn3S8) with a two-dimensional layered structure and a large birefringence. The experimental results showed that, compared with Rb10Zn4Sn4S17, Cs2ZnSn3S8 achieved the structural transition from a zero-dimensional arrangement to a two-dimensional lamellar arrangement and achieved a breakthrough of birefringence from 0 to 0.12, which was determined by both experiments and first-principles calculations. These findings demonstrated that Cs2ZnSn3S8 was a potential birefringent material and provided instructions for the study of the synthesis of birefringent materials.Herein, we propose the topotactic and self-templated fabrication of Zn1-xCdxSe porous nanobelt-ZnO nanorod (termed as ZnCdSe/ZnO) photoelectrode via the cadmium (Cd2+) ion-exchange process on zinc (Zn) foil. Inorganic-organic hybrid ZnSe(en)0.5 nanobelt (NB) was synthesized on Zn foil by a facial solvothermal method at different temperatures of 140, 160, and 180 °C for 12 h. The interfacial properties and photoelectrochemical (PEC) performance of inorganic-organic ZnSe(en)0.5 NB fabricated through the Cd2+ ion-exchange method at different time durations of 6, 12, 18, and 24 h at 140 °C were investigated. The TEM analysis results indicate that the inorganic-organic ZnSe(en)0.5 NB transformed into ZnCdSe and a self-assembled ZnO formed on the Zn foil. In particular Cd2+ ion temperature (140 °C/18 h), the optimized ZnCdSe/ZnO-(F) photoelectrode shows an excellent photocurrent density of 14 mA·cm-2 at 0 V vs Ag/AgCl with 219 μmol·cm-2 hydrogen gas evolution for 3 h under 1 sun illumination. The higher photocurrent value resulted from the optimum growth of ZnO, the formation of porous ZnCdSe, and the effective electrolyte penetration for electron-hole pair separation. The photoluminescence spectroscopy shows that the photoexcited charged carriers promoted a longer lifetime. Furthermore, we provide a full account of the possible charge-transfer mechanism during PEC hydrogen production.Visualizing cholesterol (CL) fluctuation in plasma membranes is a crucially important yet challenging task in cell biology. Here, we proposed a new imaging strategy based on permeability changes of plasma membranes triggered by different CL contents to result in controllable spatial distribution of single fluorescent probes (SF-probes) in subcellular organelles. Three spatial distribution-controllable SF-probes (PMM-Me, PMM-Et, and PMM-Bu) for imaging CL fluctuation in plasma membranes were rationally developed. These SF-probes target plasma membranes and mitochondria at normal CL levels, while they display solely staining in plasma membranes and mitochondria at increased and decreased CL levels, respectively. These polarity-sensitive probes also show distinct emission colors with fluorescence peaks of 575 and 620 nm in plasma membranes and mitochondria, respectively. Thus, the CL fluctuation in plasma membranes can be clearly visualized by means of the spatially distributed and two-color emissive SF-probes.Novel divergent domino annulation reactions of sulfur ylides with aryldiazonium tetrafluoroborates have been developed, affording various tetra- and trisubstituted pyrazole derivatives in moderate to good yields. Three molecules of sulfur ylides were applied as C1 synthon to construct the complex products with five new chemical bonds formed in these one-pot reactions.Human pluripotent stem cell (hPSC)-derived intestinal organoids (HIOs) hold unprecedented promise for basic biology and translational applications. However, developing a quantitative method to evaluate the epithelial cell membrane integrity of HIOs as an in vitro intestinal barrier model is a major challenge because of their complex three-dimensional (3D) structure. In this study, we developed an impedance system to measure the change in electrical resistance of 3D HIOs depending on the integrity of the intestinal epithelial cell membrane, which can reflect functionality and maturity. The expression of intestinal maturation- and tight junction-related markers was significantly higher in HIOs matured in vitro by treatment with IL-2 than in control HIOs. Analysis of gap junction size indicated that mature HIOs have greater integrity, with approximately 30% more compact gaps than immature HIOs. We designed a multi-microchannel system controlled by the inhalation pressure where the HIO is loaded, which enhances the stability and sensitivity of the impedance signal. We demonstrated the applicability of the impedance system by showing the difference in resistance between control and mature HIOs, reflecting the expression of tight junction proteins and their maturation status. We also validated the impedance system by monitoring its resistance in real time during junctional damage to HIOs induced by a digestive agent. In summary, we suggest a quantitative method to directly quantify the physiological changes in complex 3D organoid structures based on impedance spectroscopy, which can be applied to noninvasively monitor live cells and therefore enable their use in subsequent experiments.The influence of different synthesis routes on the structure and luminescent properties of KTb(MoO4)2 (KTMO) was studied. KTMO samples were prepared by solid-state, hydrothermal, and Czochralski techniques. These methods lead to the following different crystal structures a triclinic scheelite-type α-phase is the result for the solid-state method, and an orthorhombic KY(MoO4)2-type γ-phase is the result for the hydrothermal and Czochralski techniques. The triclinic α-KTMO phase transforms into the orthorhombic γ-phase when heated at 1273 K above the melting point, while KTMO prepared by the hydrothermal method does not show phase transitions. The influence of treatment conditions on the average crystallite size of orthorhombic KTMO was revealed by X-ray diffraction line broadening measurements. The electrical conductivity was measured on KTMO single crystals. The orthorhombic structure of KTMO that was prepared by the hydrothermal method was refined using synchrotron powder X-ray diffraction data. PCI-34051 concentration K+ cations are located in extensive two-dimensional channels along the c-axis and the a-axis. The possibility of K+ migration inside these channels was confirmed by electrical conductivity measurements, where strong anisotropy was observed in different crystallographic directions. The evolution of luminescent properties as a result of synthesis routes and heating and cooling conditions was studied and compared with data for the average crystallite size calculation and the grain size determination. All samples' emission spectra exhibit a strong green emission at 545 nm due to the 5D4 → 7F5 Tb3+ transition. The maximum of the integral intensity emission for the 5D4 → 7F5 emission under λex = 380 nm excitation was found for the KTMO crashed single crystal.Artificial spin ice systems have seen burgeoning interest due to their intriguing physics and potential applications in reprogrammable memory, logic, and magnonics. Integration of artificial spin ice with functional magnonics is a relatively recent research direction, with a host of promising results. As the field progresses, direct in-depth comparisons of distinct artificial spin systems are crucial to advancing the field. While studies have investigated the effects of different lattice geometries, little comparison exists between systems comprising continuously connected nanostructures, where spin-waves propagate via dipole-exchange interaction, and systems with nanobars disconnected at vertices, where spin-wave propagation occurs via stray dipolar field. Gaining understanding of how these very different coupling methods affect both spin-wave dynamics and magnetic reversal is key for the field to progress and provides crucial system-design information including for future systems containing combinations of connected and disconnected elements.
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