Improving the uniformity of top emitting organic light emitting diodes using a hybrid electrode structure

Funding: The authors are grateful to the Engineering and Physical Sciences Research Council (grant EP/R035164/1) for financial support.Some applications of organic light-emitting diodes (OLEDs) require large area, high light output, and high uniformity. It is difficult to achieve these attributes simultaneously because of voltage drops in the contacts, which cannot easily satisfy high optical transparency and electrical conductivity simultaneously. In large area OLEDs, thin electrodes with high sheet resistance induce voltage drops across the devices, leading to non-uniform distribution of light. However, thick electrodes with low sheet resistance decrease the light output due to low transmittance. To overcome this trade-off, a multilayer hybrid electrode based on Ag (20 nm)/WO3/Ag (20 nm)/WO3 is designed to obtain high electrical conductance with low optical loss. Compared to conventional devices using a single Ag (40 nm) top electrode, there is a considerable increase in the external quantum efficiency (EQE) of the device using this electrode (from 11.5% to 25.5% at 1000 cd m−2), while maintaining similar sheet resistance. In addition, a large area (≈57 cm2) OLED with the hybrid electrode demonstrates a luminance uniformity of 77% as compared to a device using single silver electrode with uniformity of 66%. Therefore, the proposed Ag/WO3/Ag/WO3 hybrid electrode is a promising choice for the fabrication of efficient and uniform large-area OLEDs.Publisher PDFPeer reviewe

Behavioural differences between breeding and nonbreeding pairs of protandry monogamous false clown anemonefish Amphiprion ocellaris

Anemonefishes are some of the most popular marine ornamental fishes. Due to the adverse impacts of commercial fishing on the wild populations of anemonefishes, a more suitable and efficient captive breeding programme must be promoted. In the wild, anemonefishes are protandrous sex-changing fish, but when two immature individuals with ambisexual gonads are raised together in captivity, the two differentiate directly into a male and a female, to form a breeding pair. However, not all the formed pairs spawn, explaining the great care required in captive breeding. This behaviour appears to be counter-adaptative, as anemonefish social groups form randomly in the wild, and such phenomenon would disturb their breeding success. This study evaluated the behavioural and physiological differences between breeding and nonbreeding pairs of false clown anemonefish Amphiprion ocellaris under captive conditions. Behavioural observations revealed that nonbreeding females monopolized the shelter provided, whereas breeding females allowed breeding males to use the shelter and the pair frequently stayed together in the shelter. Both nonbreeding and breeding females possessed mature ovarian tissue and similar level of plasma estradiol concentrations, but nonbreeding males had a smaller amount of testicular tissue and lower plasma 11-ketotestosterone levels compared to breeding males

ホジキン リンパシュ ノ チリョウチュウ ニ ハッショウ シタ チョウヘイソク ニ フククウキョウ ホジョカ カイジョジュツ オ シコウ シタ 1レイ

A ４０-year-old woman with stage４B Hodgkin’ s lymphoma（HL）developed small bowel obstruction during chemotherapy. The tip of long tube reached the part of stenosis and radiology and abdominal CT scan revealed a beak-like stenosis. An incarcerated internal hernia associated with strangulation or a simple adhesive intestinal obstruction was suspected and laparoscopic surgery was performed. The laparoscopic findings showed adhesion and traction of the contralateral side of mesenterium and strangulation which also intricately banded the collapsed loops of the ileum. The resected tissues showed a fibrotic stenosis of the small bowel and the greater omentum with infiltration of HL. This severe stenosis could finally be recognized by extracorporeal examination through a minor laparotomy. Laparoscopic surgery was useful procedure to observe the site of obstruction and transect complex strangulations, however more ingenuity of surgical procedure and more careful observation are essential to reliably achieve laparoscopic surgery for the small bowel obstruction

Characterization of a gene coding for a putative adenosine deaminase-related growth factor by RNA interference in the Basidiomycete Flammulina velutipes

A full-length cDNA coding for a putative adenosine deaminase (Fv-ada) was isolated from the basidiomycete Flammulina velutipes. Fv-ada encodes a polypeptide consisting of 537 amino acid residues, which has a consensus sequence conserved among adenosine deaminase-related growth factors (ADGF) found in several metazoa, including chordates and insects. Fv-ada transcript was detected at all stages of growth in dikaryotic F. velutipes cells, with a peak at the primordial stage. Heterologous expression of Fv-ada in the yeast Pichia pastoris produced recombinant Fv-ADA that catalyzed the conversion of adenosine to inosine. Dikaryotic mycelia from F. velutipes were transformed with the binary plasmid pFungiway-Fv-ada, which was designed to suppress the expression of Fv-ada through RNA interference. The growth rates of the resulting transformants were retarded in response to the degree of suppression, indicating that Fv-ada plays an important role in the mycelial growth of F. velutipes. These results suggested that ADGF could function as growth factors in fungi, as is seen in other eukaryotes.ArticleJOURNAL OF BIOSCIENCE AND BIOENGINEERING. 115(4):360-365 (2013)journal articl

Electrically driven organic laser using integrated OLED pumping

Funding: Authors thank the Engineering and Physical Sciences Research Council of the UK for the financial support from grants EP/R035164/1, EP/R03480X/1 and EP/L017008/1. J.G. thanks the China Scholarship Council (grant no. 201806100005) for financial support.Organic semiconductors are carbon-based materials that combine optoelectronic properties with simple fabrication and the scope for tuning by changing their chemical structure1,2,3. They have been successfully used to make organic light-emitting diodes2,4,5 (OLEDs, now widely found in mobile phone displays and televisions), solar cells1, transistors6 and sensors7. However, making electrically driven organic semiconductor lasers is very challenging8,9. It is difficult because organic semiconductors typically support only low current densities, suffer substantial absorption from injected charges and triplets, and have additional losses due to contacts10,11. In short, injecting charges into the gain medium leads to intolerable losses. Here we take an alternative approach in which charge injection and lasing are spatially separated, thereby greatly reducing losses. We achieve this by developing an integrated device structure that efficiently couples an OLED, with exceptionally high internal-light generation, with a polymer distributed feedback laser. Under the electrical driving of the integrated structure, we observe a threshold in light output versus drive current, with a narrow emission spectrum and the formation of a beam above the threshold. These observations confirm lasing. Our results provide an organic electronic device that has not been previously demonstrated, and show that indirect electrical pumping by an OLED is a very effective way of realizing an electrically driven organic semiconductor laser. This provides an approach to visible lasers that could see applications in spectroscopy, metrology and sensing.Publisher PDFPeer reviewe

New dimeric flavans from gambir, an extract of Uncaria gambir

Three new dimeric flavans, catechin-(4 alpha -&#62; 8)-ent-epicatechin (7), gambirflavan D1 (8), and gambirflavan D2 (9), were isolated from gambir (an extract from the leaves and young twigs of Uncaria gambir), and their structures were determined based on spectroscopic and chemical data.</p

High-Bandwidth Organic Light Emitting Diodes for Ultra-Low Cost Visible Light Communication Links

Visible light communications (VLC) have attracted considerable interest in recent years due to an increasing need for data communication links in home and enterprise environments. Organic light-emitting diodes (OLEDs) are widely used in display applications owing to their high brightness, high quality colour-rending capability and low cost. As a result, they are attractive candidates for the implementation of ultra-low cost visible light optical links in free-space and guided-wave communications. However, OLEDs need to exhibit a bandwidth of at least ~MHz to be able to support the modest data rates (~Mbps) required in these applications. Although fluorescent OLEDs typically exhibit shorter photon lifetimes than inorganic LEDs, the bandwidth performance of the large size OLEDs used in display applications are limited by their electrical characteristics. In this work, we present a detailed physical simulation that describes well the performance of fast OLED devices that exhibit significant -3 dB bandwidths (f-3dB) of 44 MHz obtained for a 0.12 mm2 device. It is demonstrated that the reduction of the device size results in a significant bandwidth improvement due primarily to a reduction in parasitic capacitance of the devices, though this is counteracted by carrier dynamic effects. The model provides an insight into the basic physical properties of the OLED and may be used for optimisation of future generations of OLED devices.EPSRC EP/K00042X/1 EPSRC Studentship 146672

Fluorescence-guided bone resection by using Visually Enhanced Lesion Scope in diffuse chronic sclerosingosteomyelitis of the mandible: clinical and pathological evaluation

Diffuse chronic sclerosingosteomyelitis (DCSO) is a refractory disease, becausethe etiology and pathogenesis remain poorly understood and to determine the border betweenunhealthy boneandhealthybone is difficult. However, progressive inflammation, clinical symptoms and a high recurrence rate of DCSO were the reasons for surgical treatment. We report a case of a 66-year old woman with DCSO of the right side of mandible who was treated with hemimandibulectomy and simultaneous reconstruction by vascularized free fibula flap. After preoperative administration of minocycline for 1 month, the bone fluorescence was successfully monitored by using a Visually Enhanced Lesion Scope (VELscope®). Intraoperatively, we could determine the resection boundaries. We investigated the clinical and histopathological findings. The fluorescence findings were well correlated with histopathological findings. Using a VELscope®was handy and useful to determine the border between DCSO lesion andhealthybone. The free fibula flap under the minocycline-derived bone fluorescence by using a VELscope®offered a good quality of mandibular bone and the successful management of an advanced and refractory DCSO

245 MHz bandwidth organic light-emitting diodes used in a gigabit optical wireless data link

Funding: UK EPSRC (EP/K00042X/I, EP/R005281/1, EP/R007101/1 and EP/R035164/1); Marie Skłodowska Curie Individual Fellowship (703387).Organic optoelectronic devices combine high-performance, simple fabrication and distinctive form factors. They are widely integrated in smart devices and wearables as flexible, high pixel density organic light emitting diode (OLED) displays, and may be scaled to large area by roll-to-roll printing for lightweight solar power systems. Exceptionally thin and flexible organic devices may enable future integrated bioelectronics and security features. However, as a result of their low charge mobility, these are generally thought to be slow devices with microsecond response times, thereby limiting their full scope of potential applications. By investigating the factors limiting their bandwidth and overcoming them, we demonstrate here exceptionally fast OLEDs with bandwidths in the hundreds of MHz range. This opens up a wide range of potential applications in spectroscopy, communications, sensing and optical ranging. As an illustration of this, we have demonstrated visible light communication using OLEDs with data rates exceeding 1 gigabit per second.Publisher PDFPeer reviewe

An Analysis of Post-text Tasks in High School English Communication Textbooks : Focusing on Reading-based Questions Enhancing Skill Integration

The goal of this short article is to analyze post-text tasks in Japanese senior high school English textbooks focusing on activities following the main texts to promote skill integration. Compared with the heightened interests in a series of textbook studies focusing on main texts, very little attention has been paid to the roles of post-text tasks in English textbooks. For this study, three senior high school English textbooks authorized by the Japanese Government were selected and their post-reading tasks were analyzed from the viewpoints of skill integration. As a result, it was found that relatively few tasks were available for skill integration in the analyzed textbooks and one advanced level textbook introduced some activities enhancing output of the learners’ own ideas and opinions