Highly Deep‐Blue Luminescent Twisted Diphenylamino Terphenyl Emitters by Bromine‐Lithium Exchange Borylation‐Suzuki Sequence

Four novel intensively blue luminescent chromophores were readily synthesized by bromine‐lithium exchange borylation‐Suzuki (BLEBS) sequence in moderate to good yields. Their electronic properties were studied by absorption and emission spectroscopy and quantum chemical calculations revealing deep‐blue emission in solution as well as in the solid state and upon embedding into a PMMA (polymethylmethacrylate) matrix with small FWHM (full width at half maximum) values and CIE y values smaller than 0.1. Moreover, high photoluminescence quantum yields (PLQY), partially close to unity, are found.

Linear Carbene Pyridine Copper Complexes with Sterically Demanding N,N'-Bis(trityl)imidazolylidene: Syntheses, Molecular Structures, and Photophysical Properties

The sterically demanding carbene ITr (N,N'-bis(triphenylmethyl)imidazolylidene) was used as a ligand for the preparation of luminescent copper(I) complexes of the type [(ITr)Cu(R-pyridine/R'-quinoline)]BF₄ (R = H, 4-CN, 4-CHO, 2,6-NH₂, and R' = 8-Cl, 6-Me). The selective formation of linear, bis(coordinated) complexes was observed for a series of pyridine and quinoline derivatives. Only in the case of 4-cyanopyridine a one-dimensional coordination polymer was formed, in which the cyano group of the cyanopyridine ligand additionally binds to another Cu atom in a bridging manner, thus leading to a trigonal planar coordination environment. In contrast, employing sterically less demanding monotrityl-substituted carbene 3, no (NHC)Cu-pyridine complexes could be prepared. Instead, a bis-carbene complex [(3)₂Cu]PF₆ was obtained which showed no luminescence. All linear pyridine/quinoline coordinated complexes show weak emission in solution but intense blue to orange luminescence doped with 10% in PMMA films and in the solid state either from triplet excited states with unusually long lifetimes of up to 4.8 ms or via TADF with high radiative rate constants of up to 1.7 × 10⁵ s^-1 at room temperature. Combined density functional theory and multireference configuration interaction calculations have been performed to rationalize the involved photophysics of these complexes. They reveal a high density of low-lying electronic states with mixed MLCT, LLCT, and LC character where the electronic structures of the absorbing and emitting state are not necessarily identical.

A tropylium annulated N-heterocyclic carbene

Derivatives of the cationic tropylium annulated imidazolylidene ITrop⁺ are obtained by hydride abstraction from related cycloheptatriene compounds. Spectroscopic, structural and theoretical data indicate that, as a cationic relative of benzimidazolylidenes, ITrop⁺ has highly reduced σ-donor and strong π-acceptor character.

Electronic Finetuning of 8-Methoxy Psoralens by Palladium-Catalyzed Coupling: Acidochromicity and Solvatochromicity

Differently 5‐substituted 8‐methoxypsoralens can be synthesized by an efficient synthetic route with various cross‐coupling methodologies, such as Suzuki, Sonogashira and Heck reaction. Compared to previously synthesized psoralens, thereby promising daylight absorbing compounds as potentially active agents against certain skin diseases can be readily accessed. Extensive investigations of all synthesized psoralen derivatives reveal fluorescence in the solid state as well as several distinctly emissive derivatives in solution. Donor‐substituted psoralens exhibit remarkable photophysical properties, such as high fluorescence quantum yields and pronounced emission solvatochromicity and acidochromicity, which were scrutinized by Lippert–Mataga and Stern–Volmer plots. The results indicate that the compounds exceed the limit of visible light, a significant factor for potential applications as an active agent. In addition, (TD)DFT calculations were performed to elucidate the underlying electronic structure and to assign experimentally obtained data.

Correction: A tropylium annulated N-heterocyclic carbene

Correction for ‘A tropylium annulated N-heterocyclic carbene’ by Sebastian Appel et al., Chem. Commun., 2020, 56, 9020–9023, DOI: 10.1039/D0CC04482B.

Computer-Aided Design of Luminescent Linear N-Heterocyclic Carbene Copper(I) Pyridine Complexes

Multireference configuration interaction methods including spin-orbit interactions have been employed to investigate the photophysical properties of various linear N-heterocyclic carbene (NHC) copper(I) pyridine complexes with the aim of designing performant thermally activated delayed fluorescence (TADF) emitters for use in organic-light-emitting diodes. Our theoretical results indicate that this structural motif is very favorable for generating excited triplet states with high quantum yield. The first excited singlet (S_MLCT) and corresponding triplet state (T_MLCT) are characterized by d_σ → π_Py metal-to-ligand charge-transfer (MLCT) excitations. Efficient intersystem crossing (ISC) and reverse ISC (rISC) between these states is mediated by a near-degenerate second triplet state (T_MLCT/LC) with large d_π → π_Py contributions. Spin-vibronic coupling is strong and is expected to play a major role in the (r)ISC processes. The calculations reveal, however, that the luminescence is effectively quenched by locally excited triplet states if the NHC ligand carries two diisopropylphenyl (DIPP) substituents. When DIPP is replaced with 1-adamantyl residues, this quenching process is suppressed and TADF in the UV spectral regime is predicted to proceed at a rate of about 1/μs. The introduction of +I substituents on the carbene and -M substituents on the pyridine allows tuning of the emission wavelength from the UV to the blue-green or green spectral region.

Flavin Monooxygenase-Generated N-Hydroxypipecolic Acid Is a Critical Element of Plant Systemic Immunity

Following a previous microbial inoculation, plants can induce broad-spectrum immunity to pathogen infection, a phenomenon known as systemic acquired resistance (SAR). SAR establishment in Arabidopsis thaliana is regulated by the Lys catabolite pipecolic acid (Pip) and flavin-dependent-monooxygenase1 (FMO1). Here, we show that elevated Pip is sufficient to induce an FMO1-dependent transcriptional reprogramming of leaves that is reminiscent of SAR. In planta and in vitro analyses demonstrate that FMO1 functions as a pipecolate N-hydroxylase, catalyzing the biochemical conversion of Pip to N-hydroxypipecolic acid (NHP). NHP systemically accumulates in plants after microbial attack. When exogenously applied, it overrides the defect of NHP-deficient fmo1 in acquired resistance and acts as a potent inducer of plant immunity to bacterial and oomycete infection. Our work has identified a pathogen-inducible L-Lys catabolic pathway in plants that generates the N-hydroxylated amino acid NHP as a critical regulator of systemic acquired resistance to pathogen infection.

Parenting and childhood obesity research: a quantitative content analysis of published research 2009-2015

BACKGROUND

A quantitative content analysis of research on parenting and childhood obesity was conducted to describe the recent literature and to identify gaps to address in future research.

METHODS

Studies were identified from multiple databases and screened according to an a priori defined protocol. Eligible studies included non-intervention studies, published in English (January 2009-December 2015) that focused on parenting and childhood obesity and included parent participants.

RESULTS

Studies eligible for inclusion (N = 667) focused on diet (57%), physical activity (23%) and sedentary behaviours (12%). The vast majority of studies used quantitative methods (80%) and a cross-sectional design (86%). Few studies focused exclusively on fathers (1%) or included non-residential (1%), non-biological (4%), indigenous (1%), immigrant (7%), ethnic/racial minority (15%) or low-socioeconomic status (19%) parents.

DISCUSSION

While results illustrate that parenting in the context of childhood obesity is a robust, global and multidisciplinary area of inquiry, it is also evident that the vast majority of studies are conducted among Caucasian, female, biological caregivers living in westernized countries. Expansion of study foci and design is recommended to capture a wider range of caregiver types and obesity-related parenting constructs, improve the validity and generalizability of findings and inform the development of culture-specific childhood obesity prevention interventions and policies. © 2016 World Obesity.

Clinical pilot study for the automatic segmentation and recognition of abdominal adipose tissue compartments from MRI data

PURPOSE

In the diagnosis and risk assessment of obesity, both the amount and distribution of adipose tissue compartments are critical factors. We present a hybrid method for the quantitative measurement of human body fat compartments.

MATERIALS AND METHODS

MRI imaging was performed on a 1.5 T scanner. In a pre-processing step, the images were corrected for bias field inhomogeneity. For segmentation and recognition a hybrid algorithm was developed to automatically differentiate between different adipose tissue compartments. The presented algorithm is designed with a combination of shape and intensity-based techniques. To incorporate the presented algorithm into the clinical routine, we developed a graphical user interface. Results from our methods were compared with the known volume of an adipose tissue phantom. To evaluate our method, we analyzed 40 clinical MRI scans of the abdominal region.

RESULTS

Relatively low segmentation errors were found for subcutaneous adipose tissue (3.56 %) and visceral adipose tissue (0.29 %) in phantom studies. The clinical results indicated high correlations between the distribution of adipose tissue compartments and obesity.

CONCLUSION

We present an approach that rapidly identifies and quantifies adipose tissue depots of interest. With this method examination and analysis can be performed in a clinically feasible timeframe.

Fast diffusion-weighted steady state free precession imaging of in vivo knee cartilage

Quantification of molecular diffusion with steady state free precession (SSFP) is complicated by the fact that diffusion effects accumulate over several repetition times (TR) leading to complex signal dependencies on transverse and longitudinal magnetization paths. This issue is commonly addressed by setting TR > T(2), yielding strong attenuation of all higher modes, except of the shortest ones. As a result, signal attenuation from diffusion becomes T(2) independent but signal-to-noise ratio (SNR) and sequence efficiency are remarkably poor. In this work, we present a new approach for fast in vivo steady state free precession diffusion-weighted imaging of cartilage with TR << T(2) offering a considerable increase in signal-to-noise ratio and sequence efficiency. At a first glance, prominent coupling between magnetization paths seems to complicate quantification issues in this limit, however, it is observed that diffusion effects become rather T(2) (ΔD ≈ 1/10 ΔT(2)) but not T(1) independent (ΔD ≈ 1/2 ΔT(1)) for low flip angles α ≈ 10 - 15°. As a result, fast high-resolution (0.35 × 0.35 - 0.50 × 0.50 mm(2) in-plane resolution) quantitative diffusion-weighted imaging of human articular cartilage is demonstrated at 3.0 T in a clinical setup using estimated T(1) and T(2) or a combination of measured T(1) and estimated T(2) values.

[Comparison between definite endocarditis and possible endocarditis according to the Duke Criteria, in a monocentric study of 45 patients]

AIM OF THE STUDY

To compare definite endocarditis (DE) and possible endocarditis (PE) according to the Duke criteria, in a monocentric cohort of 45 patients.

METHOD

From the registers of the Cardiology Department and medical database of the hospital informatic department, 45 cases of endocarditis are colliged, 29DE and 16PE.

RESULTS

DE age is 66 years, PE age is 74 years, (p<0,02), 17 male (59%) in DE, eight in PE, 21 (72%) DE have a preexisting cardiopathy versus 15 (94%) PE, seven native valve and six prosthetic valve in PE, 11 native valve and nine prosthetic valve in DE. Twenty-six (90%) DE and 16 (100%) have fever, 14 (48%) DE and nine (56%) PE have a cardiac failure, one DE (3%) and 14 (87%) have no echographic sign of endocarditis (transthoracic echo or transthoracic and transesophagal echo) (p<0.001). Blood cultures are positive in 23DE (79%), and 14 (87%) PE (NS) Streptococcus and Enterococcus are the most common bacterial species (62%) in the two groups. Treatment duration is 64 days for DE and 43 days for PE, hospitalisation duration is 33 days for the DE and 27 days in PE.

CONCLUSIONS

PE group and DE group are similar concerning fever cardiac failure, preexisting cardiopathy, blood cultures and bacterial species. PE group is older than DE group, echography is more often negative in PE group. A patient with a preexisting valvulopathy and a septicemia without echographic sign of endocarditis is the most frequent clinical pattern in PE.