Plasmonic modes of extreme subwavelength nanocavities

We study the physics of a new type of subwavelength nanocavities. They are based on U-shaped metal-insulator-metal waveguides supporting the excitation of surface plasmon polaritons. The waveguides are simultaneously excited from both sides of the U by incident plane waves. Due to their finite length discrete modes emerge within the nanocavity. We show that the excitation symmetry with respect to the cavity ends permits the observation of even and odd modes. Our investigations include near and far field simulations and predict a strong spectral far field response of the comparable small nanoresonators. The strong near field enhancement observed in the cavity at resonance might be suitable to increase the efficiency of nonlinear optical effects, quantum analogies and might facilitate the development of active optical elements, such as active plasmonic elements

Opposing land surface and air temperatures from remote sensing and Citizen Science for quantification of the Urban Heat Island effect

Extreme temperatures and heat waves are a significant risk for public health. Climate change and ongoing urbanization particularly expose urban dwellers, especially vulnerable people such as children and the elderly. In this context, the Urban Heat Island (UHI) effect describes the increased temperatures in urban areas compared to their rural surroundings. This study aims at the quantification of the UHI based on land surface temperatures measured by remote sensing, and air temperatures recorded by climate stations. Since air temperature measurements from official networks are scarce particularly in cities, measurements from Citizen Science offer a complementary source of data. First of all, this work investigates the robustness of crowdsourced air temperatures by comparison with measurements of official measurement networks. In general, we found both data sources featuring similar characteristics. Secondly, the relation of land surface and air temperature measurements is explored through statistical analysis, which showed a clear correlation that varied depending on the season. Finally, the UHI was quantified for different seasons. The strongest UHI based on land surface temperatures was measured in summer with urban-rural difference of 3.0 K. Regarding air temperatures, the highest average difference of 1.3 K was found in spring. In this manner, this study demonstrates that the incorporation of Citizen Science data enhances the knowledge on the urban climate and thus assists the development of appropriate and targeted mitigation strategies to protect the health of citizens

Impairment of Angiogenic Sphingosine Kinase-1/Sphingosine-1-Phosphate Receptors Pathway in Preeclampsia.

Preeclampsia (PE), is a serious pregnancy disorder characterized in the early gestation by shallow trophoblast invasion, impaired placental neo-angiogenesis, placental hypoxia and ischemia, which leads to maternal and fetal morbidity and mortality. Here we hypothesized that angiogenic sphingosine kinase-1 (SPHK1)/sphingosine-1-phosphate (S1P) receptors pathway is impaired in PE. We found that SPHK1 mRNA and protein expression are down-regulated in term placentae and term chorionic villous explants from patients with PE or severe PE (PES), compared with controls. Moreover, mRNA expression of angiogenic S1PR1 and S1PR3 receptors were decreased in placental samples of PE and PES patients, whereas anti-angiogenic S1PR2 was up-regulated in chorionic villous tissue of PES subjects, pointing to its potential atherogenic and inflammatory properties. Furthermore, in in vitro (JAR cells) and ex vivo (chorionic villous explants) models of placental hypoxia, SPHK1 mRNA and protein were strongly up-regulated under low oxygen tension (1% 02). In contrast, there was no change in SPHK1 expression under the conditions of placental physiological hypoxia (8% 02). In both models, nuclear protein levels of HIF1A were increased at 1% 02 during the time course, but there was no up-regulation at 8% 02, suggesting that SPHK1 and HIF1A might be the part of the same canonical pathway during hypoxia and that both contribute to placental neovascularization during early gestation. Taken together, this study suggest the SPHK1 pathway may play a role in the human early placentation process and may be involved in the pathogenesis of PE

Primer sequences used for RT-qPCR.

<p>Primer sequences used for RT-qPCR.</p

Clinical characteristics of patient and delivery.

<p>Clinical characteristics of patient and delivery.</p

Differential expression of S1P receptors (S1PR1, -2, -3) in term placentae of preeclamptic (PE), severe preeclamptic (PES) and normotensive (CTL) patients.

<p>Real-time PCR—representative bar graphs of <i>S1PR1</i> <b>(A, B)</b>, <i>S1PR3</i> <b>(C, D)</b> and <i>S1PR2</i> <b>(E, F)</b> mRNA expression normalized to 18S in CTL (n = 16), PE (n = 17) and PES (n = 9) subjects. Mean ±S.E.M, *p ≤ 0.05, Control (CTL): n = 16 versus Preeclamptic (PE): n = 17 and CTL (n = 16) versus PES (n = 9).</p

<i>SPHK1</i> mRNA and protein levels are down-regulated in term human placentae of preeclamptic patients.

<p><b>(A)</b> qRT-PCR: bar graph represents relative <i>SPHK1</i> gene expression normalized to 18S in CTL (n = 16) and PE (n = 17) subjects <b>(B)</b> SPHK1 protein expression from control (CTL) and preeclamptic (PE) placentae was determined by Western blot. Ponceau staining was used as a loading control <b>(C)</b> Bar graph represents relative SPHK1 protein abundance normalized to Ponceau stain. Mean ±S.E.M, *p ≤ 0.05, Control (CTL): n = 16, Preeclamptic (PE): n = 17.</p