Interaction-Induced ac Stark Shift of Exciton-Polaron Resonances.

Laser-induced shift of atomic states due to the ac Stark effect has played a central role in cold-atom physics and facilitated their emergence as analog quantum simulators. Here, we explore this phenomenon in an atomically thin layer of semiconductor MoSe_{2}, which we embedded in a heterostructure enabling charge tunability. Shining an intense pump laser with a small detuning from the material resonances, we generate a large population of virtual collective excitations and achieve a regime where interactions with this background population are the leading contribution to the ac Stark shift. Using this technique we study how itinerant charges modify-and dramatically enhance-the interactions between optical excitations. In particular, our experiments show that the interaction between attractive polarons could be more than an order of magnitude stronger than those between bare excitons.

Crucial role of plasmacytoid dendritic cells in the development of acute colitis through the regulation of intestinal inflammation.

Disruption of intestinal homeostasis can lead to inflammatory bowel diseases endowed susceptibility genes and environmental factors affecting intestinal accumulation and activation of colitogenic phagocytes. Plasmacytoid dendritic cells (pDCs) are immune cells that had been proposed to control innate and adaptive immunity through the massive secretion of type I interferon (IFN-I). However, the contribution of pDCs to the progression of intestinal inflammation remains unclear. Here we show a critical role of pDCs in the initiation of acute colonic inflammation using T-cell-independent acute colitis model with a selective ablation of pDCs. Although pDCs accumulated in the inflamed colon upon mucosal injury, deficiency of pDCs attenuated the development of acute colitis independent of IFN-I signaling, accompanied by the diminished colonic production of proinflammatory cytokines. Furthermore, deficiency of pDCs impaired the mobilization of colitogenic phagocytes into the inflamed colon possibly mediated by the abrogated mucosal production of C-C chemokine receptor 2 ligand. Thus, our findings highlight a critical role of pDCs in the induction of the colonic inflammation that regulates the colonic accumulation of inflammatory phagocytes leading to the initiation and exacerbation of acute colitis, and they may serve a key role in controlling gut mucosal immune homeostasis.

Serum VEGF increases in diabetic polyneuropathy, particularly in the neurologically active symptomatic stage.

AIM: To identify the relationship between vascular endothelial growth factor (VEGF) and diabetic polyneuropathy (DPN). METHODS: Two hundred and twenty diabetic patients participated, 113 with DPN and 107 without DPN. All patients were also classified according to the four stages of DPN (no neuropathy: stage 0; asymptomatic neuropathy: stage 1; symptomatic neuropathy: stage 2; disabling neuropathy: stage 3). Serum VEGF concentration was measured using an enzyme-linked immunosorbent assay (ELISA) and levels between the patients with and without DPN and also between the different stages of DPN, were compared. RESULTS: The mean serum VEGF level in all patients was 264.6 +/- 218.8 pg/ml. The mean serum VEGF level was higher in patients with DPN (310.1 +/- 224.3 pg/ml) than in the patients without DPN (216.5 +/- 204.0 pg/ml, P = 0.0014). Serum VEGF was higher in the 'symptomatic' stage (stage 2, 364.8 +/- 225.9 pg/ml) in comparison with the 'asymptomatic' (stage 1, 256.7 +/- 224.4 pg/ml, P = 0.015) and 'disabling' (stage 3, 180.3 +/- 109.4 pg/ml, P = 0.042) stages. The mean serum VEGF level in patients with diabetic retinopathy (261.1 +/- 210.6 pg/ml) and in patients with diabetic nephropathy (241.5 +/- 185.7 pg/ml) was not increased. CONCLUSIONS: The serum VEGF level is increased in patients with DPN, particularly in patients in the neurologically active 'symptomatic' stage.

Pulsed-field gel electrophoresis in differentiation of erysipelothrix species strains.

We report here the first analysis of Erysipelothrix spp. using pulsed-field gel electrophoresis (PFGE). Seventy strains of Erysipelothrix spp. were analyzed. SmaI, AscI, and NotI were tested for the ability to cleave the DNA extracted from those strains, and among them, SmaI was the most reliable enzyme. Sixty-three distinct PFGE patterns were produced, and no DNA degradation was observed, allowing the identification of all of the strains. Based on these results and on those of a previous analysis using randomly amplified polymorphic DNA and ribotyping, PFGE with SmaI might be considered to be more sensitive than those methods and to be the best method for epidemiological studies of strains of this genus.