LGR6 marks nephron progenitor cells.

BACKGROUND: Nephron progenitor cells (NPCs) undergo a stepwise process to generate all mature nephron structures. Mesenchymal to epithelial transition (MET) is considered a multistep process of NPC differentiation to ensure progressive establishment of new nephrons. However, despite this important role, to date, no marker for NPCs undergoing MET in the nephron exists. RESULTS: Here, we identify LGR6 as a NPC marker, expressed in very early cap mesenchyme, pre-tubular aggregates, renal vesicles, and in segments of S-shaped bodies, following the trajectory of MET. By using a lineage tracing approach in embryonic explants in combination with confocal imaging and single-cell RNA sequencing, we provide evidence for the multiple fates of LGR6+ cells during embryonic nephrogenesis. Moreover, by using long-term in vivo lineage tracing, we show that postnatal LGR6+ cells are capable of generating the multiple lineages of the nephrons. CONCLUSIONS: Given the profound early mesenchymal expression and MET signature of LGR6+ cells, together with the lineage tracing of mesenchymal LGR6+ cells, we conclude that LGR6+ cells contribute to all nephrogenic segments by undergoing MET. LGR6+ cells can therefore be considered an early committed NPC population during embryonic and postnatal nephrogenesis with potential regenerative capability.

Microscale cavitation as a mechanism for nucleating earthquakes at the base of the seismogenic zone.

Major earthquakes frequently nucleate near the base of the seismogenic zone, close to the brittle-ductile transition. Fault zone rupture at greater depths is inhibited by ductile flow of rock. However, the microphysical mechanisms responsible for the transition from ductile flow to seismogenic brittle/frictional behaviour at shallower depths remain unclear. Here we show that the flow-to-friction transition in experimentally simulated calcite faults is characterized by a transition from dislocation and diffusion creep to dilatant deformation, involving incompletely accommodated grain boundary sliding. With increasing shear rate or decreasing temperature, dislocation and diffusion creep become too slow to accommodate the imposed shear strain rate, leading to intergranular cavitation, weakening, strain localization, and a switch from stable flow to runaway fault rupture. The observed shear instability, triggered by the onset of microscale cavitation, provides a key mechanism for bringing about the brittle-ductile transition and for nucleating earthquakes at the base of the seismogenic zone.

Contact Allergy to Neem Oil.

A case of allergic contact dermatitis from neem oil is presented. Neem oil (synonyms: Melia azadirachta seed oil [INCI name], nim oil, margosa oil) is a vegetable (fixed) oil obtained from the seed of the neem tree Azadirachta indica by cold pressing. Contact allergy to neem oil has been described previously in only 3 patients. The allergen(s) is/are unknown.

Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.

Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis.

Severe kerion celsi due to Trichophyton mentagrophytes: a case report.

UNLABELLED: We report on a 5-year-old girl with a severe kerion celsi, caused by Trichophyton mentagrophytes, probably acquired from a pet guinea pig. The lesions had started as small irritating squamous lesions that had been accurately diagnosed as skin infection, but had only been treated with local antifungal agents. The lesions progressed and developed into a kerion celsi that had to be treated with long-term systemic griseofulvin. Nevertheless, reinfection occurred and treatment had to be restarted. The girl is left with areas of alopecia, as a result of which she is required to wear a wig. CONCLUSION: Tinea capitis is a common skin infection that should be considered in any type of scalp lesion. It requires systemic treatment, and inappropriate and delayed treatment can result in the development of kerion celsi, with sometimes devastating consequences.