Assessment of aromatic amides in printed food contact materials: analysis of potential cleavage to primary aromatic amines during simulated passage through the gastrointestinal tract.

Recent analyses conducted by German official food control reported detection of the aromatic amides N-(2,4-dimethylphenyl)acetamide (NDPA), N-acetoacetyl-m-xylidine (NAAX) and 3-hydroxy-2-naphthanilide (Naphthol AS) in cold water extracts from certain food contact materials made from paper or cardboard, including paper straws, paper napkins, and cupcake liners. Because aromatic amides may be cleaved to potentially genotoxic primary amines upon oral intake, these findings raise concern that transfer of NDPA, NAAX and Naphthol AS from food contact materials into food may present a risk to human health. The aim of the present work was to assess the stability of NDPA, NAAX and Naphthol AS and potential cleavage to 2,4-dimethylaniline (2,4-DMA) and aniline during simulated passage through the gastrointestinal tract using static in vitro digestion models.

Novel dengue virus NS2B/NS3 protease inhibitors.

Dengue fever is a severe, widespread, and neglected disease with more than 2 million diagnosed infections per year. The dengue virus NS2B/NS3 protease (PR) represents a prime target for rational drug design. At the moment, there are no clinical PR inhibitors (PIs) available.

Photoisomerization among ring-open merocyanines. II. A computational study.

The photochemical isomerization of the trans-trans-cis to the trans-trans-trans isomer of the merocyanine form of 6-nitro BIPS, which has been studied with femtosecond transient absorption spectroscopy [S. Ruetzel, M. Diekmann, P.

Photoisomerization among ring-open merocyanines. I. Reaction dynamics and wave-packet oscillations induced by tunable femtosecond pulses.

Upon ultraviolet excitation, photochromic spiropyran compounds can be converted by a ring-opening reaction into merocyanine molecules, which in turn can form several isomers differing by cis and trans configurations in the methine bridge. Whereas the spiropyran-merocyanine conversion reaction of the nitro-substituted indolinobenzopyran 6-nitro-1',3',3'-trimethylspiro[2H-1-benzopyran-2,2'-indoline] (6-nitro BIPS) has been studied extensively in theory and experiments, little is known about photoisomerization among the merocyanine isomers. In this article, we employ femtosecond transient absorption spectroscopy with variable excitation wavelengths to investigate the excited-state dynamics of the merocyanine in acetonitrile at room temperature, where exclusively the trans-trans-cis (TTC) and trans-trans-trans (TTT) isomers contribute.

Multidimensional spectroscopy of photoreactivity.

Coherent multidimensional electronic spectroscopy is commonly used to investigate photophysical phenomena such as light harvesting in photosynthesis in which the system returns back to its ground state after energy transfer. By contrast, we introduce multidimensional spectroscopy to study ultrafast photochemical processes in which the investigated molecule changes permanently. Exemplarily, the emergence in 2D and 3D spectra of a cross-peak between reactant and product reveals the cis-trans photoisomerization of merocyanine isomers.

Multiple reduction of 2,5-bis(borolyl)thiophene: isolation of a negative bipolaron by comproportionation.

The 2,5-bis(borolyl)thiophene 2, a conjugated acceptor-π-acceptor system, can be reduced to the monoradical anion [2](.-) , the dianion [2](2-) , and the tetraanion [2](4-) . The dianion [2](2-) was also prepared by a comproportionation reaction and features an absorption maximum in the near-IR region (λmax =800 nm), which is characteristic of a bipolaron with a quinoidal structure.

The electronic structure of pyracene: a spectroscopic and computational study.

We report a synthetic, spectroscopic and computational study of the polycyclic aromatic molecule pyracene, which contains aliphatic five-membered rings annealed to a naphthalene chromophore. An improved route to synthesize the compound is described. Gas-phase IR and solid-state Raman spectra agree with a ground-state D2h structure.

Oligo(borolyl)benzenes--synthesis and properties.

Herein, we report the synthesis of boroles that are linked by a conjugated phenylene spacer. The characterization of these compounds was completed by NMR and UV/Vis spectroscopy, as well as X-ray crystal diffraction. Furthermore, the coordination behavior of these oligoboroles towards five electronically and sterically disparate pyridine derivatives was studied and revealed fundamental differences in the properties of the resulting adducts.

Extraversion and its positive emotional core--further evidence from neuroscience.

Converging evidence from self-report data demonstrated that extraversion and dispositional positive affect are systematically related. Several authors therefore considered positive affect as the conceptual core of extraversion. Because the ventral striatum is regarded as a core region in the physiological basis of extraversion, the present study examines the importance of this neural substrate with a special focus on positive affect.

A clear correlation between the diradical character of 1,3-dipoles and their reactivity toward ethylene or acetylene.

A series of nine 1,3-dipoles, belonging to the families of diazonium betaines, nitrilium betaines, and azomethine betaines, has been studied by means of the breathing-orbital valence bond ab initio method. Each 1,3-dipole is described as a linear combination of three valence bond structures, two zwitterions and one diradical, for which the weights in the total wave function can be quantitatively estimated. In agreement with an early proposition of Harcourt, the diradical character of 1,3-dipoles is shown to be a critical feature to favor 1,3-dipolar cycloaddition.

Resting cerebral blood flow, attention, and aging.

Aging is accompanied by a decline of fluid cognitive functions, e.g., a slowing of information processing, working memory, and division of attention.

Latent state-trait structure of cerebral blood flow in a resting state.

Cerebral blood flow (CBF) is an important parameter for the study of brain function. The present paper examines to what extent CBF in a resting state reflects a stable latent trait and to what extent it reflects phasic situational effects. In 38 healthy subjects resting CBF was measured with continuous arterial spin labeling.

Skull thickness and magnitude of EEG alpha activity.

Objective: Electroencephalographic (EEG) research on the physiological basis of individual differences in personality or intelligence commonly presumes that between-subjects differences of EEG alpha activity reflect individual differences in brain functions. However, non-functional sources of variance such as individual differences in skull thickness may significantly contribute to individual differences in the magnitude of EEG amplitudes. Aim of the present study was to assess the association between skull thickness and the magnitude of EEG alpha activity.

Reproducibility of continuous arterial spin labeling perfusion MRI after 7 weeks.

Background: Continuous arterial spin labeling (CASL) is a non-invasive technique for the measurement of cerebral blood flow (CBF). The aim of the present study was to examine the reproducibility of CASL measurements and its suitability to consistently detect differences between groups, regions, and resting states.

Materials And Methods: Thirty-eight healthy subjects (19 female) were examined at 1.

The association of macro- and microstructure of the corpus callosum and language lateralisation.

The present study aimed to examine how differences in functional lateralisation of language are related to interindividual variations in interhemispheric connectivity. Utilising an fMRI silent word-generation paradigm, 89 left- and right-handed subjects were subdivided into four lateralisation subgroups. Applying morphological and diffusion-tensor MRI, midsagittal cross-sectional area as well as quantitative measures of molecular diffusion (anisotropy, mean diffusion) of the corpus callosum were determined to assess interhemispheric connectivity.

Handedness, dichotic-listening ear advantage, and gender effects on planum temporale asymmetry--a volumetric investigation using structural magnetic resonance imaging.

Previous research has often examined whether the asymmetrical structure of the planum temporale (PT) represents an anatomical correlate of lateralized language-processing functions, gathering diverging empirical evidence by comparing PT asymmetry in subjects with differing handedness, gender, or speech lateralization. Apart from other methodological problems, direct comparisons between studies are hampered by insufficient assessment and consideration of all three potential determinants of structural cerebral asymmetry. Based on volumetric assessment of structural Magnetic Resonance Imaging (MRI) scans of 104 healthy subjects, the present study replicated earlier observations of an overall leftward PT asymmetry, which was found to prevail irrespective of handedness, gender, or dichotic-listening ear advantage.

Alteration of cerebral perfusion in patients with idiopathic normal pressure hydrocephalus measured by 3D perfusion weighted magnetic resonance imaging.

Objective: It is controversial whether alteration of cerebral perfusion plays an important role in the pathophysiology of patients with idiopathic normal pressure hydrocephalus (NPH) and can help to predict the outcome after shunt surgery.

Materials And Methods: 28 patients with suspected NPH were examined clinically (Homburg Hydrocephalus Scale, walking test, incontinence protocol) and by 3D dynamic susceptibility based perfusion weighted magnetic resonance imaging (PWI-MRI) before and after cerebrospinal fluid release (spinal tap test, STT). The perfusion parameters (negative integral (NI), time of arrival (T0), time to peak (TTP), mean transit time, and the difference TTP-T0 were analysed.

Perfusion-weighted magnetic resonance imaging in patients with vasospasm: a useful new tool in the management of patients with subarachnoid hemorrhage.

Objective: Cerebral vasospasm (VSP) is one of the most important risk factors for the development of a delayed neurological deficit after subarachnoid hemorrhage (SAH). Perfusion-weighted magnetic resonance imaging (pwMRI) provides the possibility of detecting tissue at risk for infarction. The objective of our study was to evaluate the feasibility and impact of pwMRI in the management of SAH patients.

Effects of handedness and gender on macro- and microstructure of the corpus callosum and its subregions: a combined high-resolution and diffusion-tensor MRI study.

The corpus callosum (CC) represents the major commissural tract connecting the two cerebral hemispheres and is supposed to play crucial integrative role in functional hemispheric specialization. The present study examined whether interindividual variations in macro- and microstructure of the human CC are associated with handedness and gender. Therefore, a combined diffusion-tensor (DTI) and high-resolution morphological MRI study was performed on 34 right- and 33 left-handed subjects of both sexes.

The influence of handedness and gender on the microstructure of the human corpus callosum: a diffusion-tensor magnetic resonance imaging study.

The aim of the present study was to examine whether handedness and gender are associated with microstructural differences in human corpus callosum (CC). For this purpose, diffusion-tensor magnetic resonance imaging (DTI) was performed on 34 right- and 33 left-handed subjects of both sexes. Four quantitative variables (Mean Diffusion, Relative Anisotropy, parallel and orthogonal diffusion) were computed within the CC.