Modulation of internuclear communication in multinuclear Ruthenium(II) polypyridyl complexes

The syntheses and characterisation of a series of mononuclear and dinuclear ruthenium polypyridyl complexes based on the bridging ligands 1,3-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl]benzene, 1,4-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl]benzene, 2,5-bis-[5-(2-pyridyl)-1H-1,2,4-triazol-3-yl]thiophene, 2,5-bis-[5-pyrazinyl-1H-1,2,4-triazol-3-yl]thiophene are reported. Electrochemical studies indicate that in these systems, the ground state interaction is critically dependent on the nature of the bridging ligand and its protonation state, with strong and weak interactions being observed for thiophene- and phenylene-bridged complexes, respectively

Discovery of a Hot Symbiotic Star in the Cold Antarctic Sky: Symbiotics Are Outliers in SkyMapper uvgriz Photometry

Using near-ultraviolet flux excess and variability from the SkyMapper Southern Sky Survey11 as novel diagnostics to search for symbiotic stars?cool giants accreting onto compact objects, typically white dwarfs (WDs), we report that Hen 3-1768 (≡ASAS J195948?8252.7) is a symbiotic star. It may be an optimal target for continuous monitoring by Antarctic telescopes; at a decl. of −82877, it is now the closest known symbiotic to either geographic pole, and the only known symbiotic more southern than the Small Magellanic Cloud (Belczyński et al. 2000; Akras et al. 2019, ApJS, in press). Figure 1 shows that Hen 3-1768 produced unambiguous emission from Raman O vi 6830,7088 Å, He ii 4686 Å, and other transitions, proving that it is a symbiotic star (e.g., Shore et al. 2014). Comparing to Pickles (1998) template spectra, we preliminarily constrained the giant donor´s spectral type to between K4 and K7, making Hen 3-1768 one of the dozen or so yellow symbiotics with stellar-type infrared (IR) colors currently known (e.g., Baella et al. 2016). The 2MASS IR colors (J − H)0 = 0.82 and (H − Ks)0 = 0.21 (Skrutskie et al. 2006; de-reddened by total Galactic extinction12 ) are consistent with this conclusion (see Figure 1 in Baella et al. 2016).Fil: Lucy, Adrian B.. Columbia University; Estados UnidosFil: Sokoloski, J. L.. Columbia University; Estados UnidosFil: Nuñez, Natalia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Wolf, C.. Research School Of Astronomy And Astrophysics, Anu; AustraliaFil: Bohlsen, T.. Mirranook Observatory,; AustraliaFil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Predictive value of phasic left atrial strain analysis as a new parameter of diastolic dysfunction

Hintergrund: Der aktuellen Leitlinie zur Evaluation der diastolischen Funktion (DF) gelang durch Fokussierung auf fortgeschrittene Fälle eine Steigerung der der klinisch-prognostischen Relevanz. Problematisch ist die Zunahme unklarer Fälle. Die Analyse des linksatrialen Strains (LAS) stellt nachgewiesenermaßen ein sensitives Verfahren mit diagnostischen und prognostischen Vorteilen dar. Bei weiterhin fehlenden prognoserelevanten Therapieansätzen für die Herzinsuffizienz mit erhaltener linksventrikulärer Ejektionsfraktion (HFpEF) scheint die Prädiktion einer zukünftigen Entwicklung oder Verschlechterung einer diastolischen Dysfunktion (DD) von zentraler Bedeutung. Die prädiktiven Eigenschaften eines reduzierten LAS für den Verlauf der DD wurden bisher nicht evaluiert. Ziel und Methoden: Nach einem mittleren Nachbeobachtungszeitraum von 6.8 Jahren wurden bei 249 der ehemals 449 Teilnehmerinnen der Berliner Frauen Risikoevaluation (BEFRI) Echo-Substudie erneut klinische und echokardiographische Daten erhoben. Ziel war die Beschreibung der DF und des Stellenwerts eines initial reduzierten LAS für die Entstehung oder Progression einer DD in einem prospektiven longitudinalen Studiendesign. Neben deskriptiven Kreuztabellen und Analysen von Mittelwertsunterschieden wurde diese Beziehung mittels Receiver Operating Characteristic (ROC) Kurvenanalyse und multivariaten logistischen Regressionsmodellen untersucht und mit anderen Standardparametern der DD verglichen. Ergebnisse: 40 Teilnehmerinnen entwickelten eine diastolische Funktionsverschlechterung (16,1 %). Von diesen zeigten initial 22,5 % einen vergrößerten linksatrialen Volumenindex (LAVI), 57,5 % eine reduzierte Mitralanulusgeschwindigkeit e‘ und 90,0 % einen reduzierten linksatrialen reservoir Strain (LASr). Der linksatriale conduit Strain (LAScd) zeigte sich in der Ausgangsuntersuchung bei Frauen mit initial unauffälliger DF, die im Verlauf eine DD entwickelten, signifikant (p –17,5 % (Sensitivität 83 %; Spezifität 73 %). In der multivariaten logistischen Regression zeigten einzig LASr und LAScd eine signifikante Assoziation mit einer zukünftigen diastolischen Funktionsverschlechterung. Schlussfolgerung: Neben einer bereits beschriebenen frühen Diagnosestellung der DD und einer deutlichen Reduktion unklarer Fälle ermöglicht die Analyse des LAS die Vorhersage einer zukünftigen Verschlechterung der DF.Background: Recent recommendations for the evaluation of diastolic function (DF) achieved an improvement in clinical and prognostic relevance by focusing on advanced cases. Problematic seems an increase of indeterminate cases. Left atrial strain (LAS) analysis represents a sensitive method, reportedly offering better diagnostic and prognostic significance. While evidence-based prognostically relevant therapy is still lacking in heart failure with preserved ejection fraction (HFpEF), identification of individuals who are at risk for future development or progression of diastolic dysfunction (DD) seems of particular importance. The predictive value of a reduced LAS for the future course of DF has not been yet evaluated. Aim and Methods: After a mean follow-up period of 6,8 years 249 of previously 449 female participants of a former echocardiographic sub study (baseline exam) of the Berlin Female Risk Evaluation (BEFRI) study have been reevaluated by a comprehensive clinical and echocardiographic examination. The aims have been the description of DF and evaluation of the significance of an initially reduced LAS for subsequent development and progression of DD in a prospective longitudinal study design. In addition to contingency tables and analyses of differences of mean, this relation was additionally evaluated and compared to established echocardiographic DD parameters by receiver operating characteristic (ROC) curve analyses and multivariate logistic regression analyses. Results: 40 participants developed a deterioration of DF (16,1%). Of those 22,5% showed initially an enlarged left atrial volume index (LAVI), 57,5% a reduced mitral annulus early diastolic velocity e’ and 90,0% a reduced left atrial reservoir strain (LASr). The initial left atrial conduit strain (LAScd) was significantly (p –17,5 % (sensitivity 83%; specificity 73%) respectively. In multivariate logistic regression analyses only LASr and LAScd remained significant predictors for a deterioration of DF. Conclusion: In addition to the previously described early diagnosis of DD and the marked reduction of indeterminate DD cases, LAS has the ability to predict a future deterioration of DF

First principles calculation of inhomogeneous broadening in solid-state cw-EPR spectroscopy

We present a scheme for the first-principles calculation of EPR lineshapes for continuous-wave-EPR spectroscopy (cw-EPR) of spin centers in complex chemical environments. We specifically focus on poorly characterized systems, e.g. powders and frozen glasses with variable microsolvation structures. Our approach is based on ab initio molecular dynamics simulations and ab initio calculations of the ensemble of g- and A-tensors along the trajectory. The method incorporates temperature effects as well as the full anharmonicity of the intra- and intermolecular degrees of freedom of the system. We apply this scheme to compute the lineshape of a prototypical spin probe, the nitrosodisulfonate dianionic radical (Fremy's salt), dissolved in a 50 : 50 mixture of water and methanol. We are able to determine the specific effect of variations of local solvent composition and microsolvation structure on the cw-EPR lineshape. Our molecular dynamics reveal a highly anisotropic solvation structure with distinct spatial preferences for water and methanol around Fremy's salt that can be traced back to a combination of steric and polar influences. The overall solvation structure and conformational preferences of Fremy's salt as found in our MD simulations agree very well with the results obtained from EPR and orientation-selective ENDOR spectroscopy performed on the frozen glass. The simulated EPR lineshapes show good agreement with the experimental spectra. When combined with our MD results, they characterize the lineshape dependence on local morphological fluctuations

Benzoxazine/amine-based polymer networks featuring stress-relaxation and reprocessability

Amines as additives in benzoxazines are known to beneficially affect the polymerization temperature and furthermore to allow for partially reversible reaction steps yielding however a non-dynamic polybenzoxazine network. This contribution proves that the polymerization behavior of a two-component polymer of the polyetheramine Jeffamine® ED-600 and a bisphenol-A-based benzoxazine features stress-relaxation and reprocessability usually known from vitrimers. With the aim to gain a deeper understanding of the material properties of this system and the corresponding polymer structure, the reaction mechanism of a monofunctional benzoxazine and monoamine model system was studied revealing at first primary, and then secondary amine induced opening of oxazine rings, leading at first to linear polymer chains and then to covalently crosslinked networks. Both consist of repeated phenolic benzoxazine/amine motifs with permanently incorporated polyetheramine chains that do not impact the mechanical properties, compared to pure polybenzoxazine. Thermal, spectroscopic, and extraction analyses show that the addition of Jeffamine® reduces the polymerization temperature and introduces material properties such as reprocessability at the same time. Stress-relaxation measurements support the assumption that the reprocessability point to vitrimer-like molecular processes. The material shows rapid stress-relaxation of up to 11 s, a corresponding bond-exchange activation energy of 146 kJ/mol, and a topology freezing temperature of 97°C

The cyclin-dependent kinase inhibitor Orysa;KRP1 plays an important role in seed development of rice

Kip-related proteins (KRPs) play a major role in the regulation of the plant cell cycle. We report the identification of five putative rice (Oryza sativa) proteins that share characteristic motifs with previously described plant KRPs. To investigate the function of KRPs in rice development, we generated transgenic plants overexpressing the Orysa; KRP1 gene. Phenotypic analysis revealed that overexpressed KRP1 reduced cell production during leaf development. The reduced cell production in the leaf meristem was partly compensated by an increased cell size, demonstrating the existence of a compensatory mechanism in monocot species by which growth rate is less reduced than cell production, through cell expansion. Furthermore, Orysa; KRP1 overexpression dramatically reduced seed filling. Sectioning through the overexpressed KRP1 seeds showed that KRP overproduction disturbed the production of endosperm cells. The decrease in the number of fully formed seeds was accompanied by a drop in the endoreduplication of endosperm cells, pointing toward a role of KRP1 in connecting endocycle with endosperm development. Also, spatial and temporal transcript detection in developing seeds suggests that Orysa; KRP1 plays an important role in the exit from the mitotic cell cycle during rice grain formation

Device layout dependence of PBTI in back-gated IGZO TFTs

The attractive electrical and processing properties of IGZO-based TFTs make these devices promising in various applications, but primarily in BEOL logic and DRAM cells [1,2]. IGZO has been shown to meet the performance requirements of many applications such as display and DRAM selectors [2]. However, the reliability of industry relevant gate-dielectric based IGZO devices has been only recently tackled [3,4]. In addition, the role of device layout and channel geometry (depending on the target application) has not been investigated. In this work we systematically study BTI degradation in 2 main families of back-gated IGZO transistors based on a 10nm thermally grown SiO2 as gate-dielectric, each one differing in S/D access geometry and/or channel width. In the first one, the S/D contacts have very large area with ~5000μm2 (M0 devices), while the second one is based on much smaller contact area of 135nm × device width W (M1 device) (Fig1, left). For each family, gate lengths Lg spanning 2 orders of magnitude (from ~200nm to ~30μm) are investigated to detect short channel effects. Vth0 is extracted at a fixed current level of 100pA×W/L for both architectures (Fig 1., middle). While M0 devices suffer from a decrease of Vth0 as a function of Lg, the Vth of M1 devices is very stable for all measured Lg. Please click Download on the upper right corner to see the full abstract

Fluorescence lifetime imaging ophthalmoscopy and the influence of oral lutein/zeaxanthin supplementation on macular pigment (FLOS) - A pilot study.

BACKGROUND & AIMS Oral lutein (L) and zeaxanthin (Z) supplementation enhances macular pigment optical density (MPOD) and plays a protective role in the development of age-related macular degeneration (AMD). Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a novel in vivo retinal imaging method that has been shown to correlate to classical MPOD measurements and might contribute to a metabolic mapping of the retina in the future. Our aim was to show that oral supplementation of L and Z affects the FLIO signal in a positive way in patients with AMD. METHODS This was a prospective, single center, open label cohort study. Patients with early and intermediate AMD received oral L and Z supplementation during three months, and were observed for another three months after therapy termination. All visits included measurements of clinical parameters, serum L and Z concentration, MPOD measurements using heterochromatic flicker photometry, dual wavelength autofluorescence imaging, and FLIO. Correlation analysis between FLIO and MPOD were performed. RESULTS Twenty-one patients completed the follow up period. Serum L and Z concentrations significantly increased during supplementation (mean difference 244.8 ng/ml; 95% CI: 81.26-419.9, and 77.1 ng/ml; 95% CI: 5.3-52.0, respectively). Mean MPOD units significantly increased (mean difference 0.06; 95% CI: 0.02-0.09; at 0.5°, 202; 95% CI: 58-345; at 2°, 1033; 95% CI: 288-1668; at 9° of eccentricity, respectively) after three months of supplementation with macular xanthophylls, which included L and Z. Median FLIO lifetimes in the foveal center significantly decreased from 277.3 ps (interquartile range 230.2-339.1) to 261.0 ps (interquartile range 231.4-334.4, p = 0.027). All parameters returned to near-normal values after termination of the nutritional supplementation. A significant negative correlation was found between FLIO and MPOD (r2 = 0.57, p < 0.0001). CONCLUSIONS FLIO is able to detect subtle changes in MPOD after L and Z supplementation in patients with early and intermediate AMD. Our findings confirm the previous described negative correlation between FLIO and MPOD. Macular xanthophylls seem to contribute to short foveal lifetimes. This study is registered at ClinicalTrials.gov (identifier number NCT04761341)