Increasing incidence of Trichophyton tonsurans in Munich-A single-centre observation.

BACKGROUND: Tinea capitis and tinea corporis are highly prevalent fungal skin infections, which globally are mainly caused by Microsporum canis and Trichophyton rubrum, respectively. While in the United States and Great Britain Trichophyton tonsurans is widely prevalent as a causative pathogen, it so far only plays a minor role in Germany. OBJECTIVES: Since the frequency of pathogenic species varies regionally and temporally, this study assesses the proportion of Trichophyton tonsurans infections in the dermatology department of a large university hospital in Germany from 2019 to 2022 and thoroughly characterises the affected patient population. PATIENTS/METHODS: This retrospective study at the Technical University of Munich analyses mycological culture results regarding the identified dermatophyte and infection site. Detailed patient and disease-related information on Trichophyton tonsurans positive patients was obtained. RESULTS: In 2022, 23 patients of 111 dermatophyte culture-positive patients tested positive for Trichophyton tonsurans. This accounted for 20.7% and represented a tenfold increase from 2.1% in 2019. Contact sports were only practiced by 21.7% of patients, and no common hotspot or other linkage could be identified between the cases. Additionally, 47.8% of the patients received a systemic treatment, with 30.4% visiting the clinic more than three times. In 2022, 21.7% were diagnosed with a simultaneous infection of the capillitium and body, whereas this was only observed in 7.1% of cases in 2019 to 2021. CONCLUSIONS: This study suggests an increase of Trichophyton tonsurans infections via several routes of transmission.

Computational study of the effect of dispersion interactions on the thermochemistry of aggregation of fused polycyclic aromatic hydrocarbons as model asphaltene compounds in solution.

Density functional theory (DFT), Møller-Plesset second-order perturbation theory (MP2), and semiempirical methods are employed for the geometry optimization and thermochemistry analysis of π-π stacked di-, tri-, tetra-, and pentamer aggregates of the fused polycyclic aromatic hydrocarbons (PAHs) naphthalene, anthracene, phenanthrene, tetracene, pyrene, and coronene as well as benzene. These aggregates (stabilized by dispersion interactions) are highly relevant to the intermolecular aggregation of asphaltenes, major components of heavy petroleum. The strength of π-π stacking interaction is evaluated with respect to the π-stacking distance and thermochemistry results, such as aggregation enthalpies, entropies, and Gibbs free energies (ΔG(298)). For both π-stacking interplanar distances and thermochemistry, the ωB97X-D functional with an augmented damped R(-6) dispersion correction term and MP2 are in the closest agreement with the highly accurate spin-component scaled MP2 (SCS-MP2) method that we selected as a reference. The ΔG(298) values indicate that the aggregation of coronene is spontaneous at 298 K and the formation of pyrene dimers occurs spontaneously at temperature lower than 250 K. Aggregates of smaller PAHs would be stable at even lower temperature. These findings are supported by X-ray crystallographic determination results showing that among the PAHs studied only coronene forms continuous stacked aggregates in single crystals, pyrene forms dimers, and smaller PAHs do not form π-π stacked aggregates. Thermochemistry analysis results show that PAHs containing more than four fused benzene rings would spontaneously form aggregates at 298 K. Also, round-shaped PAHs, such as phenanthrene and pyrene, form more stable aggregates than linear PAHs, such as anthracene and tetracene, due to decreased entropic penalty. These results are intended to help guide the synthesis of model asphaltene compounds for spectroscopic studies so as to help understand the aggregation behavior of heavy petroleum.

Li+ alumino-silicate ion source development for the neutralized drift compression experiment.

We report results on lithium alumino-silicate ion source development in preparation for warm dense matter heating experiments on the new neutralized drift compression experiment II. The practical limit to the current density for a lithium alumino-silicate source is determined by the maximum operating temperature that the ion source can withstand before running into problems of heat transfer, melting of the alumino-silicate material, and emission lifetime. Using small prototype emitters, at a temperature of ≈1275 °C, a space-charge limited Li(+) beam current density of J ≈1 mA/cm(2) was obtained. The lifetime of the ion source was ≈50 h while pulsing at a rate of 0.033 Hz with a pulse duration of 5-6 µs.

Visualization and quantification of the anisotropic effect of C=C double bonds on 1H NMR spectra of highly congested hydrocarbons-indirect estimates of steric strain.

The anisotropic effect of the olefinic C=C double bond has been calculated by employing the NICS ( nucleus independent chemical shift) concept and visualized as an anisotropic cone by a through space NMR shielding grid. Sign and size of this spatial effect on (1)H chemical shifts of protons in norbornene, exo- and endo-2-methylnorbornenes, and in three highly congested tetracyclic norbornene analogs have been compared with the experimental (1)H NMR spectra as far as published. (1)H NMR spectra have also been calculated at the HF/6-31G* level of theory to get a full, comparable set of proton chemical shifts. Differences between delta( (1)H)/ppm and the calculated anisotropic effect of the CC double bond are discussed in terms of the steric compression that occurs in the compounds studied.

Absolute measurement of electron-cloud density in a positively charged particle beam.

Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse.

Preparation of alpha-diazocarbonyl compounds from beta-lapachone derivatives and other 1,2-naphthoquinones: use of the 2D NMR 1H,15N and 1H,13C HMBC techniques in assigning regiochemistry.

The assignment of the diazo site in products of the reaction of p-toluenesulfonylhydrazine with beta-lapachone, 3,4-dihydro-2,2-dimethyl-2H-naphtho[1,2-b]pyran-5,6-dione, and other 1,2-naphthoquinones in methanol solution at room temperature has been accomplished using 1H,13C HMBC and 1H,15N HMBC NMR experiments. Only one diazo-naphthalenone product was isolated in yields ranging from 50-100% from each reaction. The site of diazo substitution of beta-lapachone and derivatives is the 1-position, in contrast to substitution at the 2-position in 4-MeO-1,2-naphthoquinone. Steric factors, rather than electronic factors, control the reaction site. Along with 2-diazo-1(2H)-naphthalenone, an additional product isolated from the reaction of p-toluenesulfonylhydrazide with 1,2-naphthoquinone was 2-diazo-4-hydroxy-1(2H)-naphthalenone. Confirmation of the formation of 6-diazo-2,2-dimethyl-2,3,4,6-tetrahydro-2H-benzo[h]cromen-5-one, obtained from beta-lapachone, was achieved using single crystal X-ray diffraction.

Interpretation of conformational effects on 2-endo-norborneol by natural chemical shielding analysis.

This paper represents an extension of our work on the (1)H and (13)C NMR chemical shifts of norbornane and 2-endo-norborneol. NCS-NBO analysis was employed to probe contributions of bond orbitals and orbitals of lone pairs to nuclear shielding in conformers of the alcohol generated by rotation of the C-O bond. Variations in (1)H and (13)C chemical shifts with the dihedral angle are discussed in terms of Lewis and non-Lewis partitioning and their respective importance is evaluated. In addition to hyperconjugation of the lone pair in a p orbital of oxygen that was previously reported, a sizable participation of the lone pair which is in an sp orbital is also observed and their combined effect dominates the carbon chemical shifts of the C(1)-C(2)-OH and C(3)-C(2)-OH fragments. Both lone pairs on oxygen also contribute to localized, though-space effects on nuclei in the vicinity, these effects answering for the largest deviations in hydrogen chemical shifts on rotation around the C-O bond. On the other hand, for conformers in which nonbonded repulsions lead to distortions in the molecular framework, variations in chemical shifts may be attributed to angular effects.

Pharmaceuticals from natural products: current trends.

The use of products extracted from plants for medicinal purposes can be traced to the beginnings of civilization and up until the end of the nineteenth century natural products were the principal source of medicines. Since then their relative importance has oscillated according to the strategies of large pharmaceutical companies. Now that these strategies are changing, there are new opportunities for countries like Brazil, in which a large proportion of the world's biodiversity is located. There are, however, new circumstances that must be taken into consideration: material must be collected by groups which are formally authorized to do so and under the conditions of the Convention of Biological Diversity, the discovery process is being successively outsourced to smaller specialized firms and there is a growing integration with producers of cosmetics and phytomedicines.

Pharmaceuticals from natural products: current trends

The use of products extracted from plants for medicinal purposes can be traced to the beginnings of civilization and up until the end of the nineteenth century natural products were the principal source of medicines. Since then their relative importance has oscillated according to the strategies of large pharmaceutical companies. Now that these strategies are changing, there are new opportunities for countries like Brazil, in which a large proportion of the world's biodiversity is located. There are, however, new circumstances that must be taken into consideration: material must be collected by groups which are formally authorized to do so and under the conditions of the Convention of Biological Diversity, the discovery process is being successively outsourced to smaller specialized firms and there is a growing integration with producers of cosmetics and phytomedicines

Prospects for Brazilian natural products

Interest in natural products as a source of bioactive substances seems to be on the rise again. The parmaceutical industry, the largest and most visible segment that develops and sells products based on active principles, is undergoing changes that will probably affect its way of doing business and conducting research. Recourse to what is often referred to as "alternative medicine" has stimulated a surge in the consumption of phytomedicines and dietary supplements, while a growing awareness that the Earthïs biodiversity is a valuable resource has provided a strong impetus for conservation and/or sustainable development of important ecosystems. Prospects for countries like Brazil, that are rich in natural prducts, could be very favorable if an institucional framework capable of linking researchers in the area with world markets can be organized.