Publications by authors named "KIRSCHBAUM T"

Negatively curved nanographenes are considered as cutouts of three-dimensional fully sp-hybridized carbon allotropes such as Schwarzites. Here we present the synthesis of a C cut-out of the Schwarzite 8-4-1-p proposed by Lenosky et al. and investigate its optical as well as electrochemical properties.

View Article and Find Full Text PDF

Aqueous nanodiamonds illuminated by UV light produce free solvated electrons, which may drive high-energy reduction reactions in water. However, the influence of water conformations on the excited-state electron-transfer mechanism are still under debate. In this work, we offer a theoretical study of charge-transfer states in adamantane-water structures obtained by linear-response time-dependent density-functional theory.

View Article and Find Full Text PDF

Nanodiamonds (NDs) are unique carbonaceous materials with exceptionally high stability, hardness, and notable electronic properties. Their applications in photocatalysis, biomedicine, and energy materials are usually carried out in aqueous environments, where they interact with aqueous adsorbates. Especially, electron density may rearrange from the diamond material toward oxidative adsorbates such as oxygen, which is known as charge transfer doping.

View Article and Find Full Text PDF

Polycyclic aromatic hydrocarbons (PAHs) containing odd-membered rings (such as pentagons or heptagons) are fascinating synthetic targets. A special case is the introduction of five- and seven-membered rings in form of an azulene unit. Azulene itself is an aromatic compounds known for its deep blue color, which is a result of its internal dipole moment.

View Article and Find Full Text PDF

Nanodiamonds have a wide range of applications including catalysis, sensing, tribology, and biomedicine. To leverage nanodiamond design via machine learning, we introduce the new data set ND5k, consisting of 5089 diamondoid and nanodiamond structures and their frontier orbital energies. ND5k structures are optimized via tight-binding density functional theory (DFTB) and their frontier orbital energies are computed using density functional theory (DFT) with the PBE0 hybrid functional.

View Article and Find Full Text PDF

Mechanically interlocked structures, such as catenanes and rotaxanes, are fascinating synthetic targets and some are used for molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three-dimensional shape-persistent organic cages forming such structures have been reported. However, the catenation in all these cases was based on a thermodynamically favoured π-π-stacking under certain reaction conditions.

View Article and Find Full Text PDF

Solvated electrons are among the most reductive species in an aqueous environment. Diamond materials have been proposed as a promising source of solvated electrons, but the underlying emission process in water remains elusive so far. Here, we show spectroscopic evidence for the emission of solvated electrons from detonation nanodiamonds upon excitation with both deep ultraviolet (225 nm) and visible (400 nm) light using ultrafast transient absorption.

View Article and Find Full Text PDF

Background: Effective equity-focused health policy for hypertension in low- and middle-income countries (LMICs) requires an understanding of the condition's current socioeconomic gradients and how these are likely to change in the future as countries develop economically.

Objectives: This cross-sectional study aimed to determine how hypertension prevalence in LMICs varies by individuals' education and household wealth, and how these socioeconomic gradients in hypertension prevalence are associated with a country's gross domestic product (GDP) per capita.

Methods: We pooled nationally representative household survey data from 76 LMICs.

View Article and Find Full Text PDF

The pollution of groundwater with nitrate is a serious issue because nitrate can cause several diseases such as methemoglobinemia or cancer. Therefore, selective removal of nitrate by efficient binding to supramolecular hosts is highly desired. Here we describe how to make [2+3] amide cages in very high to quantitative yields by applying an optimized Pinnick oxidation protocol for the conversion of corresponding imine cages.

View Article and Find Full Text PDF

Anthropogenic greenhouse gases contribute to global warming. Among those gases, perfluorocarbons (PFCs) are thousands to tens of thousands of times more harmful to the environment than comparable amounts of carbon dioxide. To date, materials that selectively adsorb perfluorocarbons in favor of other less harmful gases have not been reported.

View Article and Find Full Text PDF

Nanodiamonds (NDs) are modern high-potential materials relevant for applications in biomedicine, photocatalysis, and various other fields. Their electronic surface properties, especially in the liquid phase, are key to their function in the applications, but we show that they are sensitively modified by their interactions with the environment. Two important interaction modes are those with oxidative aqueous adsorbates as well as ND self-aggregation towards the formation of ND clusters.

View Article and Find Full Text PDF

Background As screening programs in low- and middle-income countries (LMICs) often do not have the resources to screen the entire population, there is frequently a need to target such efforts to easily identifiable priority groups. This study aimed to determine (1) how hypertension prevalence in LMICs varies by age, sex, body mass index, and smoking status, and (2) the ability of different combinations of these variables to accurately predict hypertension. Methods and Results We analyzed individual-level, nationally representative data from 1 170 629 participants in 56 LMICs, of whom 220 636 (18.

View Article and Find Full Text PDF

Background: Current hypertension guidelines vary substantially in their definition of who should be offered blood pressure-lowering medications. Understanding the effect of guideline choice on the proportion of adults who require treatment is crucial for planning and scaling up hypertension care in low- and middle-income countries.

Methods: We extracted cross-sectional data on age, sex, blood pressure, hypertension treatment and diagnosis status, smoking, and body mass index for adults 30 to 70 years of age from nationally representative surveys in 50 low- and middle-income countries (N = 1 037 215).

View Article and Find Full Text PDF

A six-step synthesis towards a tribenzotriquinacene (TBTQ) bearing three quinoxalinophenanthrophenazine (QPP) units is presented. The optoelectronic properties are investigated and the effect of the three-dimensional arrangement of the individual QPP planes is examined using optical spectroscopy, electrochemical analysis and quantum-chemical calculations.

View Article and Find Full Text PDF

Since a few years, the interest in negatively-curved fused polycyclic aromatic hydrocarbons (PAHs) has significantly increased. Recently, the first chiral negatively-curved PAH with the topology of a monkey saddle was introduced. Herein the synthesis of its triaza congener is reported.

View Article and Find Full Text PDF

A new synthetic route to tetraindenopyrene (TIP)-a bowl-shaped cut-out structure of C -is reported. The key step in this approach is a fourfold palladium-catalyzed C-H activation that increases the yield more than 50 times in comparison to the approach originally described by Scott and co-workers. Besides examination of its optoelectronic properties and study of its aggregation in solution, TIP was also re-investigated by dispersion-corrected DFT methods, which showed that dispersion interactions significantly increase the bowl-to-bowl inversion barrier.

View Article and Find Full Text PDF
Article Synopsis
  • Three imine cages with tetrahedral geometry were tested for their ability to encapsulate different tetra-alkylammonium salts in various solvents.
  • In dichloromethane, the cage with the smallest window only captures NEt but not NMe, while larger cages accommodate both ions.
  • Kinetic experiments and molecular simulations were conducted to understand uptake mechanisms, and additional NMR studies were performed to explore the complexation of pharmaceutical compounds like acetylcholine and muscarine.
View Article and Find Full Text PDF

A contorted polycyclic aromatic hydrocarbon (PAH) in the shape of a monkey saddle has been synthesized in three steps from a readily available truxene precursor. The monkey saddle PAH is consisting of three five-, seven six-, and three eight-membered rings and has been unambiguously characterized by single-crystal X-ray diffraction. Owing to the three biaryl axes the monkey saddle PAH is inherently chiral.

View Article and Find Full Text PDF

The oxidative cyclodehydrogenation (often named the Scholl reaction) is still a powerful synthetic tool to construct even larger polycyclic aromatic hydrocarbons (PAHs) by multiple biaryl bond formations without the necessity of prior installation of reacting functional groups. Scholl-type reactions are usually very selective although the resulting products bear sometimes some surprises, such as the formation of five-membered instead of six-membered rings or the unexpected migration of aryl moieties. There are a few examples, where chlorinated byproducts were found when FeCl was used as reagent.

View Article and Find Full Text PDF

Purpose: Treatment effect or radiation necrosis after stereotactic radiosurgery (SRS) for brain metastases is a common phenomenon often indistinguishable from true progression. Radiomics is an emerging field that promises to improve on conventional imaging. In this study, we sought to apply a radiomics-based prediction model to the problem of diagnosing treatment effect after SRS.

View Article and Find Full Text PDF

In the version of this article initially published, the line graph showing TNF-α levels in Fig. 2d was inadvertently duplicated. A graph of IL-6 levels should be shown in place of the duplication.

View Article and Find Full Text PDF

Lung-innervating nociceptor sensory neurons detect noxious or harmful stimuli and consequently protect organisms by mediating coughing, pain, and bronchoconstriction. However, the role of sensory neurons in pulmonary host defense is unclear. Here, we found that TRPV1 nociceptors suppressed protective immunity against lethal Staphylococcus aureus pneumonia.

View Article and Find Full Text PDF

Extended fused aromatic compounds are promising materials for organic electronics. Among them, structures with five-membered annulated rings differ from those consisting only of six-membered carbocyclic rings. To date, fusion of five-membered rings has been realized mainly via the [b]-edge, and systems fused via the [c]-edge are of low stability.

View Article and Find Full Text PDF