Kondo quasiparticle dynamics observed by resonant inelastic x-ray scattering.

Effective models focused on pertinent low-energy degrees of freedom have substantially contributed to our qualitative understanding of quantum materials. An iconic example, the Kondo model, was key to demonstrating that the rich phase diagrams of correlated metals originate from the interplay of localized and itinerant electrons. Modern electronic structure calculations suggest that to achieve quantitative material-specific models, accurate consideration of the crystal field and spin-orbit interactions is imperative. This poses the question of how local high-energy degrees of freedom become incorporated into a collective electronic state. Here, we use resonant inelastic x-ray scattering (RIXS) on CePd3 to clarify the fate of all relevant energy scales. We find that even spin-orbit excited states acquire pronounced momentum-dependence at low temperature-the telltale sign of hybridization with the underlying metallic state. Our results demonstrate how localized electronic degrees of freedom endow correlated metals with new properties, which is critical for a microscopic understanding of superconducting, electronic nematic, and topological states.

Pressure-Induced Excitations in the Out-of-Plane Optical Response of the Nodal-Line Semimetal ZrSiS.

The anisotropic optical response of the layered, nodal-line semimetal ZrSiS at ambient and high pressure is investigated by frequency-dependent reflectivity measurements for the polarization along and perpendicular to the layers. The highly anisotropic optical conductivity is in very good agreement with results from density-functional theory calculations and confirms the anisotropic character of ZrSiS. Whereas the in-plane optical conductivity shows only modest pressure-induced changes, we found strong effects on the out-of-plane optical conductivity spectrum of ZrSiS, with the appearance of two prominent excitations. These pronounced pressure-induced effects can neither be attributed to a structural phase transition according to our single-crystal x-ray diffraction measurements, nor can they be explained by electronic correlation and electron-hole pairing effects, as revealed by theoretical calculations. Our findings are discussed in the context of the recently proposed excitonic insulator phase in ZrSiS.

Women with threatened preterm labour followed by term delivery have an increased risk of spontaneous preterm birth in subsequent pregnancies: a population-based cohort study.

OBJECTIVES: To evaluate the association of a history of threatened preterm labour (TPL) followed by term delivery with the risk of spontaneous preterm delivery (PTD) in subsequent pregnancy. DESIGN: Population-based cohort study. SETTING: Data of the National Health Insurance Claims Database and a national health-screening programme for infants and children in South Korea. POPULATION: Women who had their first singleton delivery in 2010 and a subsequent second singleton delivery between 2011 and 2015. METHODS: Multivariable analysis adjusting for maternal age and interval between first and second deliveries was used to assess the risk of PTD based on PTD, TPL followed by term delivery, and term delivery in the first pregnancy. MAIN OUTCOME MEASURES: The risk of PTD during the second pregnancy. RESULTS: This study included 115 629 women with two consecutive deliveries during the study period. Spontaneous PTD rates in the second pregnancy were 7.71, 2.22 and 1.02% in women with PTD, TPL followed by term delivery, and term delivery in the first pregnancy, respectively. Threatened preterm labour followed by term delivery in the first pregnancy was associated with increased risk of PTD in the subsequent pregnancy after adjustment for potential confounding factors (adjusted odds ratio 2.21; 95% CI 1.76-2.78). CONCLUSION: Although women with a history of TPL followed by term delivery had a lower risk of PTD during a subsequent pregnancy compared with those with history of previous PTD, they still had a significantly increased risk of PTD compared with those who delivered at term without TPL. TWEETABLE ABSTRACT: The history of threatened preterm labour followed by term delivery is related to increased risk of subsequent spontaneous preterm delivery.

Operational strategies for an activated sludge process in conjunction with ozone oxidation for zero excess sludge production during winter season.

A pilot-scale activated sludge system coupled with sludge ozonation process was operated for 112 days of a winter season without excess sludge wasting. The concept of this process is that the excess sludge produced is first disintegrated by ozone oxidation and then recirculated to a bioreactor in order to mineralize the particulate and soluble organic compounds. The basis of operation was to determine either the optimal amount of sludge in kg SS ozonated each day (SO) or the optimal ozonation frequency under the variable influent chemical oxygen demand (COD) loading and temperature conditions, since the ozone supply consumes costly energy. The optimal SO was obtained using the theoretically estimated sludge production rate (SP) and experimentally obtained ozonation frequency (n). While the SP was mainly subject to the COD loadings, sludge concentration was affected by the temperature changes in winter season. The optimal n was observed between 2.5 and 2.7 at around 15 degrees C, but it was doubled at 10 degrees C. Mixed liquor suspended solids (MLSS) concentration was leveled off at around 5000 mg/L in bioreactor at 15 degrees C, but the volatile fraction of MLSS was fixed around 0.7 indicating that there was no significant inorganic accumulation. Suspended solids (SS) and soluble COD in effluents kept always a satisfactory level of 10 and 15 mg/L with sufficient biodegradation. It was recommended to apply a dynamic SO under variable influent COD loadings and temperature conditions to the activated sludge system without excess sludge production for saving energy as well as system stabilization.

Use of autotrophic sulfur-oxidizers to remove nitrate from bank filtrate in a permeable reactive barrier system.

This study was conducted to evaluate the potential applicability of an in situ biological reactive barrier system to treat nitrate-contaminated bank filtrate. The reactive barrier consisted of sulfur granules as an electron donor and autotrophic sulfur-oxidizing bacteria as a biological component. Limestone was also used to provide alkalinity. The results showed that the autotrophic sulfur oxidizers were successfully colonized on the surfaces of the sulfur particles and removed nitrate from synthetic bank filtrate. The sulfur-oxidizing activity continuously increased with time and then was maintained or slightly decreased after five days of column operation. Maximum nitrate removal efficiency and sulfur oxidation rate were observed at near neutral pH. Over 90% of the initial nitrate dissolved in synthetic bank filtrate was removed in all columns tested with some nitrite accumulation. However, nitrite accumulation was observed mainly during the initial operation period, and the concentration markedly diminished with time. The nitrite concentration in effluent was less than 2 mg-N/l after 12 days of column operation. When influent nitrate concentrations were 30, 40, and 60 mg-N/l and sulfur content in column was 75%, half-order autotrophic denitrification reaction rate constants were 31.73 x 10(-3), 33.3 x 10(-3), and 36.4 x 10(-3) mg(1/2)/l(1/2)min, respectively. Our data on the nitrate distribution profile along the column suggest that an appropriate wall thickness of a reactive barrier for autotrophic denitrification may be 30 cm when influent nitrate concentration is less than 60 mg-N/l.

Spectral correlation in incommensurate multiwalled carbon nanotubes.

We investigate the energy spectra of clean incommensurate double-walled carbon nanotubes, and find that the overall spectral properties are described by the critical statistics similar to that known in the Anderson metal-insulator transition. In the energy spectra, there exist three different regimes characterized by Wigner-Dyson, Poisson, and semi-Poisson distributions. This feature implies that the electron transport in incommensurate multiwalled nanotubes can be either diffusive, ballistic, or intermediate between them, depending on the position of the Fermi energy.

New hybrid ligands with a trans-1,2-diaminocyclohexane backbone: competing chelation modes in palladium-catalyzed enantioselective allylic alkylation

Three new hybrid ligands with trans-1,2-diaminocyclohexane backbone have been synthesized from (1R,2R)-2-aminocyclohexylcarbamic acid tert-butyl ester (4), which is prepared through an indirect monoprotection of the diamine. The ligands are (1R, 2R)-N-2-[2-(dimethylamino)benzoyl]aminocyclohexyl-2-(diphenylphosph anyl)benzamide and its di-n-butylamino- and diphenylamino-derivatives (3a-c), which belong to formal P,N-type chelates with possible wide bite angles in the metal chelation. To evaluate the new hybrid ligands against well-known P,N- and P, P-chelates (1 and 2), they were employed in the palladium-catalyzed allylic alkylations between two standard racemic allylic acetates, 2-acetoxy-1,3-diphenyl-2-propene (14a) and 2-acetoxy-1, 3-dimethyl-2-propene (14b), and dimethyl malonate under different reaction conditions. The catalytic system with the new ligands showed good reactivity toward both the substrates with moderate enantioselectivities (up to 78% ee toward 14a and 80% ee toward 14b). Of particular note, dramatic changes in the sense and in the degree of the enantioselectivity were observed depending on the ligands and reaction conditions, which suggested a different chelation mode was competing with the supposed P,N-chelation mode. An X-ray crystal structure of a chelated palladium complex [Pd(3c)(eta(3)-PhCHCHCHPh)]PF(6) was obtained, which showed a P, O-chelation mode in which a carboxamide oxygen acted as the O-ligand. This is the first example of the enantioselective palladium-catalyzed allylic alkylation in which a P,O-chelated complex of a carboxamide group participated as the ligand group.

Novel artificial receptors for alkylammonium ions with remarkable selectivity and affinity

The benzene-based tripodal tris(oxazolines) have been developed as the most selective and strong receptors toward linear alkylammonium ions reported to date. Among six tris(oxazolines) based on 2,4,6-trimethylbenzene framework, the phenylglycinol-derived receptor 4 exhibits the largest association constant toward nBuNH3+ (logK(ass) = 6.65 +/- 0.02), while a similar value toward tBuNH3+, (logK(ass) = 3.80 +/- 0.01) compared with others, which corresponds to the selectivity ratio of nBuNH3+/tBuNH3+ as high as approximately equals 700. The tris(oxazoline) 6 that has bare oxazoline ring exhibits still a large association constant toward sterically hindered tBuNH3+ (logK(ass) = 5.26 +/- 0.02). Both receptors 4 and 6 extract beta-phenethylammonium ion from water into chloroform almost completely. When the benzene frame is changed from 2,4,6-trimethylbenzene to 2,4,6-triethylbenzene, dramatic changes in the affinity as well as in the selectivity are observed. The association constant observed by tris(oxazoline) 8 toward nBuNH3+ approaches 10(8)M(-1) and the selectivity ratio of nBuNH3+/tBuNH3+ is increased to 2,700. This selectivity is even more enhanced to 4,000 with tris(oxazoline) 9. The enhanced binding affinity and high selectivity observed with receptors 4 and related derivatives 7-9 compared with others can be explained by an optimized steric and electronic environment provided by the phenyl substituents, which has been unambiguously demonstrated by X-ray crystallographic and 1H NMR spectroscopic studies on the host-guest complexes. The new receptor system has several unique features such as ready availability, structural simplicity, and in particular, versatility in derivatization. By virtue of these advantages, it can be readily tailored as selective receptors toward biologically important amines.

Suppressed beta-hydride elimination in palladium-catalyzed cascade cyclization-coupling reactions: an efficient synthesis of 3-arylmethylpyrrolidines

[formula: see text] A novel type of palladium-catalyzed cascade cyclization-coupling reaction that proceeds with suppressed beta-hydride elimination has been found. One of the N-sulfonyl oxygens is suggested to coordinatively stabilize an alkylpalladium intermediate, thus preventing the intermediate from the usual beta-elimination. This is the first sequential palladium-catalyzed coupling reaction where the Suzuki and Heck reactions can compete. The reaction provides an efficient synthetic route to 4-methylene-3-arylmethylpyrrolidines, which are not readily available by other routes.