Mask Acne (Maskne): A New Variant of Acne Mechanica

Mask acne (maskne) is the new variant of acne mechanica, associated with personal protective equipment usage in healthcare workers. Widespread daily use of facial masks for many hours during the COVID-19 pandemic has been linked to the development of new acne or exacerbation of the previous acne over the masked area, with a distinct pattern, referred to as the “O” zone area around the mouth. Maskne can be caused by friction, irritation, local increase in skin temperature, and humidity, the same mechanism as observed in acne mechanica. Keywords: Maskne; Pathophysiology; Diagnosis; Treatment; Prevention

Influence of the laser cutting front geometry on the striation formation analysed with high-speed synchrotron X-ray imaging

The generation of low surface roughness of the cut edge during laser beam cutting is a challenge. The striation pattern, which determines the surface roughness, can be distinguished into regular and interrupted striations, the latter resulting in an increased surface roughness. In order to analyse their formation, the space- and time-resolved cutting front geometry and melt film thickness were captured during laser beam fusion cutting of aluminium sheets with a framerate of 1000 Hz by means of high-speed synchrotron X-ray imaging. The comparison of the contours of the cutting fronts for a cut result with regular und interrupted striations shows that the contour fluctuates significantly more in case of interrupted striations. This leads to a strong fluctuation of the local angle of incidence. In addition, the average angle of incidence decreases, which results in an increase of the average absorbed irradiance. Both phenomena, local increase of absorbed irradiance and its dynamic fluctuation, result in a local increase of the melt film thickness at the cutting front which is responsible for the formation of the interrupted striations.

Infestation of Norway spruce seedlings by Cryphalus asperatus: New threat for planting of forests?

Cryphalus asperatus (Coleoptera: Curculionidae, Scolytinae) is described as an exceptional but important secondary pest of Norway spruce seedlings. Of the 10 000 seedlings transported to one location in the Ore Mountains, Central Europe in 2020, in total 1 500 seedlings were killed by C. asperatus. The infestation and death of seedlings probably resulted in part from the substantial local increase in the local abundance of C. asperatus after the sanitation felling of many Ips typographus-infested and otherwise damaged trees; the felled trees provided many branches suitable for C. asperatus feeding. In addition, the seedlings were probably stressed by the multi-hour transportation (probably drought) from the forest nursery.

Sequestration within biomolecular condensates inhibits Aβ-42 amyloid formation

Biomolecular condensates sequester an aggregation-prone peptide and prevent its aggregation, showing that heterotypic interactions within the condensates can prevent the formation of amyloid fibrils, despite the local increase in concentration.

Karhart’s notch in ear diseases

According to the literature and our research, Karhart’s notch, as a local increase in bone conduction thresholds at frequencies of 500-3000 Hz, is observed not only in otosclerosis, but also in other diseases of the middle ear, especially – with adhesive and secretory otitis. Therefore, it is not appropriate to use the presence of a Karhart’s notch as a pathognomonic sign of otosclerosis. Audiometric diagnostics of non-purulent ear diseases should definitely be supplemented with impedance audiometry.

EVALUATION OF THE RESIDUAL STRESSES LEVEL FORMED DURING THE COOLING OF THE TITANIUM-STEEL BIMETAL

The level of internal stresses arising in the titanium VT1-0 + steel 08kp bimetal during cooling was estimated by methods of finite element modeling. It is shown that the intermetallic layer formed during diffusion annealing leads to a sharp local increase in the residual internal equivalent Mises stresses with a slight decrease in the stresses normal to the interface.