Focus Issue: Organic light-emitting diodes-status quo and current developments.

The guest editors introduce the Optics Express Energy Express supplement Focus Issue, "Organic Light-Emitting Diodes," which includes six invited articles addressing the challenges of light outcoupling and light management in OLEDs.

Formation of intra-island grain boundaries in pentacene monolayers.

To assess the formation of intra-island grain boundaries during the early stages of pentacene film growth, we studied sub-monolayers of pentacene on pristine silicon oxide and silicon oxide with high pinning centre density (induced by UV/O(3) treatment). We investigated the influence of the kinetic energy of the impinging molecules on the sub-monolayer growth by comparing organic molecular beam deposition (OMBD) and supersonic molecular beam deposition (SuMBD). For pentacene films fabricated by OMBD, higher pentacene island-density and higher polycrystalline island density were observed on UV/O(3)-treated silicon oxide as compared to pristine silicon oxide.

[New developments in skin reconstruction - cell cultures and skin substitutes plus review of the literature].

The management of patients with deep extensive burns remains a major challenge for reconstructive surgeons. This is especially true with the considerable progress that is currently being achieved in resuscitation procedures that permit the survival of patients with burns in over 90% of their body surface. Modern reconstruction techniques have had to innovate and become a complex surgery requiring a strategic plan involving materials and multiple surgical procedures tailored to each clinical situation.

γ-Interferon-regulated chaperone governs human lymphocyte antigen class II expression.

Antigen presentation by human lymphocyte antigen (HLA) class II peptide receptors alerts the immune system to infections. In antigen-presenting cells (APCs), HLA class II, HLA-DM, and associated invariant chain-encoding genes are exclusively regulated by the interferon γ (IFNγ)-inducible class II transactivator (CIITA). Control of CIITA expression could therefore govern expression of class II peptide receptors in the diverse group of APCs.

The functions of the actin nucleator Cobl in cellular morphogenesis critically depend on syndapin I.

Spatial control of cortical actin nucleation is indispensable for proper establishment and plasticity of cell morphology. Cobl is a novel WH2 domain-based actin nucleator. The cellular coordination of Cobl's nucleation activity, however, has remained elusive.

Electronic properties of interfaces between PCPDTBT and prototypical electrodes studied by photoemission spectroscopy.

We report on the electronic structure of poly[2,6-(4,4-bis- (2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), a promising low-band-gap donor material for efficient bulk heterojunction organic solar cells. Electronic properties of interfaces formed between PCPDTBT and prototypical electrodes [Au, indium-tin-oxide and poly(ethylene-dioxythiophene): poly(styrenesulfonate)], obtained from X-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy, are evaluated. The formation of interface dipoles is observed, and their consequences for device performance are discussed.

Band bending in conjugated polymer layers.

We use the Kelvin probe method to study the energy-level alignment of four conjugated polymers deposited on various electrodes. Band bending is observed in all polymers when the substrate work function exceeds critical values. Through modeling, we show that the band bending is explained by charge transfer from the electrodes into a small density of states that extends several hundred meV into the band gap.

Simple proposal for dosimetry with an Elekta iViewGT™ electronic portal imaging device (EPID) using commercial software modules.

Background: An electronic portal imaging device (EPID) is used to control for patient setup and positioning during fractionated radiotherapy. Due to the rising complexity and conformity of irradiation techniques, the demand for an accurate verification of the dose delivered to the patient has also increased. The purpose of this study was to investigate a simple guidance for dosimetry with an Elekta iViewGT™ EPID using commercial software modules.

Calibration of the Gamma Knife Perfexion using TG-21 and the solid water Leksell dosimetry phantom.

Purpose: To calibrate a Gamma Knife (GK) Perfexion using TG-21 with updated chamber-dependent values for modern microionization chambers in the new solid water Leksell dosimetry phantom. This work illustrates a calibration method using commercially available equipment, instruments, and an established dosimetry protocol that may be adopted at any GK center, thus reducing the interinstitutional variation in GK calibration. The calibration was verified by three third-party dosimetry checks.

Stoichiometry of HLA class II-invariant chain oligomers.

Background: The HLA gene complex encodes three class II isotypes, DR, DQ, and DP. HLA class II molecules are peptide receptors that present antigens for recognition by T lymphocytes. In antigen presenting cells, the assembly of matched α and β subunits to heterodimers is chaperoned by invariant chain (Ii).

Core, shell, and surface-optimized dendrimers for blue light-emitting diodes.

We present a novel core-shell-surface multifunctional structure for dendrimers using a blue fluorescent pyrene core with triphenylene dendrons and triphenylamine surface groups. We find efficient excitation energy transfer from the triphenylene shell to the pyrene core, substantially enhancing the quantum yield in solution and the solid state (4-fold) compared to dendrimers without a core emitter, while TPA groups facilitate the hole capturing and injection ability in the device applications. With a luminance of up to 1400 cd/m(2), a saturated blue emission CIE(xy) = (0.

Site-specific geometric and electronic relaxations at organic-metal interfaces.

The correlation between the geometric and electronic structures of Zn-phthalocyanine (ZnPc) and F16ZnPc on Cu(111) were studied by x-ray standing wave and angle-resolved photoemission spectroscopy. We found evidence for a distortion of the planar molecules upon adsorption, with the central Zn atom in the molecule protruding towards the substrate. This modifies the energy levels of both the molecule and the substrate, which appear as interface states.

Density-dependent reorientation and rehybridization of chemisorbed conjugated molecules for controlling interface electronic structure.

The adsorption of the molecular acceptor hexaazatriphenylene-hexacarbonitrile on Ag(111) was investigated as function of layer density. We find that the orientation of the first molecular layer changes from a face-on to an edge-on conformation depending on layer density, facilitated through specific interactions of the peripheral molecular cyano groups with the metal. This is accompanied by a rehybridization of molecular and metal electronic states, which significantly modifies the interface and surface electronic properties, as rationalized by theoretical modeling.

Band-offset engineering in organic/inorganic semiconductor hybrid structures.

Control over the electronic structure of organic/inorganic semiconductor interfaces is required to realize hybrid structures with tailored opto-electronic properties. An approach towards this goal is demonstrated for a layered hybrid system composed of p-sexiphenyl (6P) and ZnO. The molecular orientation can be switched from "upright-standing" to "flat-lying" by tuning the molecule-substrate interactions through aggregation on different crystal faces.

Electronic structure of large disc-type donors and acceptors.

Searching for new pi-conjugated charge-transfer systems, the electronic structure of a new acceptor-donor pair derived from coronene (C(24)H(12)) was investigated by ultraviolet photoelectron spectroscopy (UPS). The acceptor coronene-hexaone (C(24)H(6)O(6), in the following abbreviated as COHON) and the donor hexamethoxycoronene (C(30)H(24)O(6), abbreviated as HMC) were adsorbed as pure and mixed phases on gold substrates. At low coverage, COHON adsorption leads to the appearance of a charge-transfer induced interface state 1.

Development and verification of an analytical algorithm to predict absorbed dose distributions in ocular proton therapy using Monte Carlo simulations.

Proton beam radiotherapy is an effective and non-invasive treatment for uveal melanoma. Recent research efforts have focused on improving the dosimetric accuracy of treatment planning and overcoming the present limitation of relative analytical dose calculations. Monte Carlo algorithms have been shown to accurately predict dose per monitor unit (D/MU) values, but this has yet to be shown for analytical algorithms dedicated to ocular proton therapy, which are typically less computationally expensive than Monte Carlo algorithms.

A new monoclonal antibody recognizing a linear determinant on the HLA-DRalpha chain N-terminus.

We report the generation of a monoclonal antibody (MAb) that reacts to the N-terminus of the denatured HLA-DRalpha chain. The 1C4.6 MAb was raised against a peptide corresponding to amino acid residues 10 to 32 of a highly conserved region within the alpha1 domain of HLA-DR.

The herpes simplex virus-1 encoded glycoprotein B diverts HLA-DR into the exosome pathway.

Neutralizing Abs play an important role for immunity against HSV-1 infection. This branch of the immune response is initiated by MHC class II Ag presentation and activation of T cell help. In this study, we show that the HSV-1 encoded glycoprotein B (gB) manipulates the class II processing pathway by perturbing endosomal sorting and trafficking of HLA-DR (DR) molecules.

Impact of a pain protocol including hypnosis in major burns.

Background: Pain is a major issue after burns even when large doses of opioids are prescribed. The study focused on the impact of a pain protocol using hypnosis on pain intensity, anxiety, clinical course, and costs.

Methods: All patients admitted to the ICU, aged >18 years, with an ICU stay >24h, accepting to try hypnosis, and treated according to standardized pain protocol were included.

A high molecular weight donor for electron injection interlayers on metal electrodes.

The molecular donor 9,9'-ethane-1,2-diylidene-bis(N-methyl-9,10-dihydroacridine) (NMA) has been synthesized, and its electronic properties were characterized both in solution using cyclic voltammetry and optical absorption spectroscopy, and at interfaces to metals with photoelectron spectroscopy (PES). The optical energy gap of NMA in solution increases by 0.10 eV when the compound is doubly oxidized.

Transparent, highly conductive graphene electrodes from acetylene-assisted thermolysis of graphite oxide sheets and nanographene molecules.

Transparent and highly conductive graphene electrodes have been fabricated through acetylene-assisted thermolysis of graphite oxide (GO) sheets. This novel procedure uses acetylene as a supplemental carbon source to repair substantial defects within GO sheets, leading to the enhancement of graphitization of synthesized graphene electrodes. The as-prepared graphene on quartz substrates exhibits an electrical conductivity of 1425 S cm(-1) with an optical transmittance of more than 70% at a wavelength of 500 nm.

Superantigen-presentation by rat major histocompatibility complex class II molecules RT1.Bl and RT1.Dl.

Rat major histocompatibility complex (MHC) class II molecules RT1.B(l) (DQ-like) and RT1.D(l) (DR-like) were cloned from the LEW strain using reverse transcription-polymerase chain reaction and expressed in mouse L929 cells.

MHC class II molecules activate NFAT and the ERK group of MAPK through distinct signaling pathways in B cells.

MHC class II (MHC-II) molecules are capable of transducing signals with the help of associated molecules. Although the search to find associated molecules over the past few years has been fruitful, it remains clear that not all signaling components and their mechanisms of action have been identified. In this study, we investigated calcium and MAPK signaling pathways using the BJAB and Raji human B cell lines.

IL-10 protects monocytes and macrophages from complement-mediated lysis.

Phagocytes, such as monocytes and macrophages, are important cells of the innate immunity in the defense against microbes. So far, it is unclear how these cells survive at the site of combat against microbes, where a hostile inflammatory environment prevails with strong complement activity. We hypothesized that IL-10, a key cytokine involved in the resolution of inflammation, induces resistance to complement attack.