Efficient and Stable Solution-Processed Organic Light Emitting Transistors using a High-k Dielectric

We report the development of highly efficient and stable solution-processed organic light emitting transistors (OLETs) that combine a polymer heterostructure with the transparent high-k dielectric poly(vinylidenefluoride0.62-trifluoroethylene0.31-chlorotrifluoroethylene0.7) (P(VDF-TrFE-CTFE)). The polymer heterostructure comprises of the poly[4-(4,4- dihexadecyl-4H-cyclopenta[1,2-b:5,4-b’]dithiophen-2-yl)-alt-[1,2,5]thiadiazolo[3,4- c]pyridine] (PCDTPT) and Super Yellow as charge transporting and light emitting layers, respectively. Device characterization shows that the use of P(VDF-TrFE-CTFE) leads to larger channel currents (≈2 mA) and lower operating voltages (-35 V) than for previously reported polymer based OLETs. Furthermore, the combined transparency of the dielectric and gate electrode, results in efficient bottom emission with external quantum efficiency of ≈0.88 % at a luminance L ≥ 2000 cd m−2. Importantly, the resulting OLETs exhibit excellent shelf life and operational stability. The present work represents a significant step forward in the pursuit of all-solution-processed OLET technology for lighting and display applications

Lattice Green's function approach to the solution of the spectrum of an array of quantum dots and its linear conductance

In this paper we derive general relations for the band-structure of an array of quantum dots and compute its transport properties when connected to two perfect leads. The exact lattice Green's functions for the perfect array and with an attached adatom are derived. The expressions for the linear conductance for the perfect array as well as for the array with a defect are presented. The calculations are illustrated for a dot made of three atoms. The results derived here are also the starting point to include the effect of electron-electron and electron-phonon interactions on the transport properties of quantum dot arrays. Different derivations of the exact lattice Green's functions are discussed

Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Luminous Infrared Galaxy Candidates

We present Spitzer 3.6 and 4.5 $\mu$m photometry and positions for a sample of 1510 brown dwarf candidates identified by the WISE all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12); Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify 7 fainter (4.5 $\mu$m $\sim$ 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy (HyLIRG) candidates. For this control sample we find another 6 brown dwarf candidates, suggesting that the 7 companion candidates are not physically associated. In fact, only one of these 7 Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this there is no evidence for any widely separated ($>$ 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of $\sim$ 7.33 $\times 10^5$ objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 $\mu$m photometry, along with positionally matched $B$ and $R$ photometry from USNO-B; $J$, $H$, and $K_s$ photometry from 2MASS; and $W1$, $W2$, $W3$, and $W4$ photometry from the WISE all-sky catalog

Functional analysis of antibodies against dengue virus type 4 reveals strain-dependent epitope exposure that impacts neutralization and protection

Although prior studies have characterized the neutralizing activities of monoclonal antibodies (MAbs) against dengue virus (DENV) serotypes 1, 2, and 3 (DENV-1, DENV-2, and DENV-3), few reports have assessed the activity of MAbs against DENV-4. Here, we evaluated the inhibitory activity of 81 new mouse anti-DENV-4 MAbs. We observed strain- and genotype-dependent differences in neutralization of DENV-4 by MAbs mapping to epitopes on domain II (DII) and DIII of the envelope (E) protein. Several anti-DENV-4 MAbs inefficiently inhibited at least one strain and/or genotype, suggesting that the exposure or sequence of neutralizing epitopes varies within isolates of this serotype. Remarkably, flavivirus cross-reactive MAbs, which bound to the highly conserved fusion loop in DII and inhibited infection of DENV-1, DENV-2, and DENV-3, more weakly neutralized five different DENV-4 strains encompassing the genetic diversity of the serotype after preincubation at 37°C. However, increasing the time of preincubation at 37°C or raising the temperature to 40°C enhanced the potency of DII fusion loop-specific MAbs and some DIII-specific MAbs against DENV-4 strains. Prophylaxis studies in two new DENV-4 mouse models showed that neutralization titers of MAbs after preincubation at 37°C correlated with activity in vivo. Our studies establish the complexity of MAb recognition against DENV-4 and suggest that differences in epitope exposure relative to other DENV serotypes affect antibody neutralization and protective activity

Policy challenges for the pediatric rheumatology workforce: Part III. the international situation

Survival dominates current pediatric global health priorities. Diseases of poverty largely contribute to overall mortality in children under 5 years of age. Infectious diseases and injuries account for 75% of cause-specific mortality among children ages 5-14 years. Twenty percent of the world's population lives in extreme poverty (income below US $1.25/day). Within this population, essential services and basic needs are not met, including clean water, sanitation, adequate nutrition, shelter, access to health care, medicines and education. In this context, musculoskeletal disease comprises 0.1% of all-cause mortality in children ages 5-14 years. Worldwide morbidity from musculoskeletal disease remains generally unknown in the pediatric age group. This epidemiologic data is not routinely surveyed by international agencies, including the World Health Organization. The prevalence of pediatric rheumatic diseases based on data from developed nations is in the range of 2,500 - 3,000 cases per million children. Developing countries' needs for musculoskeletal morbidity are undergoing an epidemiologic shift to chronic conditions, as leading causes of pediatric mortality are slowly quelled