Highly-Directional,Highly-Efficient Solution-Processed Light-Emitting Diodes of All-Face-Down Oriented Colloidal Quantum Well Self-Assembly

Semiconductor colloidal quantum wells (CQWs) provide anisotropic emission behavior originating from their anisotropic optical transition dipole moments (TDMs). Here, solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) of a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that collectively enable a supreme level of IP TDMs at 92% in the ensemble emission are shown. This significantly enhances the outcoupling efficiency from 22% (of standard randomly-oriented emitters) to 34% (of face-down oriented emitters) in the LED. As a result, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with the hybrid organic-inorganic evaporation-based CQW-LEDs and all other best solution-processed LEDs. This SAM-CQW-LED architecture allows for a high maximum brightness of 19,800 cd m⁻² with a long operational lifetime of 247 h at 100 cd m⁻² as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV at a current density of 1 mA cm⁻² and a high J₉₀ of 99.58 mA cm⁻². These findings indicate the effectiveness of oriented self-assembly of CQWs as an electrically-driven emissive layer in improving outcoupling and external quantum efficiencies in the CQW-LEDs.     

Learning model-free robot control by a Monte Carlo EM algorithm

We address the problem of learning robot control by model-free reinforcement learning (RL). We adopt the probabilistic model for model-free RL of Vlassis and Toussaint (Proceedings of the international conference on machine learning, Montreal, Canada, 2009), and we propose a Monte Carlo EM algorithm (MCEM) for control learning that searches directly in the space of controller parameters using information obtained from randomly generated robot trajectories. MCEM is related to, and generalizes, the PoWER algorithm of Kober and Peters (Proceedings of the neural information processing systems, 2009). In the finite-horizon case MCEM reduces precisely to PoWER, but MCEM can also handle the discounted infinite-horizon case. An interesting result is that the infinite-horizon case can be viewed as a ‘randomized’ version of the finite-horizon case, in the sense that the length of each sampled trajectory is a random draw from an appropriately constructed geometric distribution. We provide some preliminary experiments demonstrating the effects of fixed (PoWER) vs randomized (MCEM) horizon length in two simulated and one real robot control tasks.     

Side chain functional carbazole-fluorene electroactive polymers: Optical,electrochemical properties,antimicrobial activity and thin film morphologies

A new electroactive polymer based on fluorene and carbazole moieties with double bond side chain (MP25) was synthesized and then double bond at the side chain was functionalized with  COOH and  Si(OEt)₃ as ITO/glass compatible groups. Electrochemical and optical properties of the polymers were elucidated with cyclic voltammetry (CV), ultraviolet–visible absorption (UV–Vis), and photoluminescence (PL) spectroscopy. It was observed that all polymers absorbed only the UV region and emitted blue light. By using CV, HOMO values were found as approximately 5.45 eV. According to AFM results, when the rough MP25 polymer thin film was modified with ITO/glass compatible groups, more uniform and smoother polymer thin films were obtained. Thermogravimetry analyses (TGA) shown that the MP25-Si and MP25-COOH were stable against thermo-oxidative decomposition. The weight loss of MP-25-Si was found to be only %23 at 700°C. Additionally, antimicrobial activity of MP25 polymers was also investigated. According to test results, all polymers were found to have antimicrobial activity against C.albicans.     

In-source and post-irradiation polymerization of acenaphthylene in the solid state

Radiation-induced solid state polymerization of acenaphthylene was studied by using ⁶⁰Co γ-rays. The extent of polymerization at room temperature reached 68% when acenaphthylene was irradiated with a dose of 2–5 MGy. Prolonged exposure to the radiation decreased the molecular weight of the polymers. The post-polymerization of acenaphthylene was found to occur at relatively high temperatures close to the melting point of acenaphthylene. Absence of an effective termination step allows the enhancement of post-polymerization at higher temperatures after a limiting conversion is accomplished.     

Computer-assisted teaching and assessment of disabled students in higher education: the interface between academic standards and disability rights

Abstract  Computer-assisted teaching and assessment has become a regular feature across many areas of the curriculum in higher education courses around the world in recent years. This development has resulted in the 'digital divide' between disabled students and their nondisabled peers regarding their participation in computer-assisted courses. However, there has been a long-standing practice to ensure that disabled students could participate in these courses with a set of disability adjustments that are in line with their learning modalities under the headings of presentation format, response format, timing, and setting adjustments. Additionally, there has been a set of supporting antidiscriminatory disability laws around the world to avoid such divide between disabled students and their nondisabled peers. However, following a successful pre cedent in Davis v. Southeastern Community College (1979), the opponents of disability rights have consistently argued that making disability adjustments for disabled students to participate in computer-assisted courses would undermine academic and professional standards and these laws have resulted in a 'culture of fear' among the staff. This paper challenges such myths and argues, based on a systematic review of four major antidiscriminatory laws, that universities have full academic freedom to set the academic standards of their computer-assisted courses despite the introduction of such laws and that there has been no grounds for the perceived culture of fear about the consequences of the participation of disabled students in computer-assisted courses.     

Cytokine repertoire during maturation of monocytes to macrophages within spheroids of malignant and non-malignant urothelial cell lines

Terminal maturation of human blood monocytes to macrophages (MAC) in vivo is believed to be important for the morphology, antigen expression and functional activity of the resulting MAC population. This process is modulated by the specific tissue micro-environment to which blood monocytes migrate upon leaving the vasculature. Tumor-associated macrophages (TAM) are a special type of MAC, and little is known about the modulating capacity of the tumor environment on monocyte-to-MAC differentiation. By co-culturing 3-dimensional multicellular spheroids (MCS) of the urothelial-bladder-carcinoma cell lines J82 and RT4 with human monocytes/MAC we generated TAM in vitro. For comparison, monocytes/MAC were co-cultured with the non-tumorigenic urothelial cell line HCV29. The effects on monocyte differentiation were analyzed, particularly with respect to cytokine release. Monocyte maturation was modulated within the tumor spheroid dependent upon the tumor cell type. Monocytes co-cultured with MCS of the poorly differentiated J82 carcinoma spontaneously produced high amounts of IL-1beta and IL-6, but only low amounts of TNF-alpha, which could be further increased by the addition of LPS. This cytokine pattern is characteristic for monocytes and remained constant for up to 8 days in J82-MCS co-cultures. However, in RT4-MCS and HCV29-MCS co-cultures, the initial cytokine pattern changed and after 8 days corresponded well to that of MAC differentiated in vitro without tumor contact. In addition to functional parameters, we analyzed the morphology of J82-MCS-TAM and found that they displayed a monocyte-like morphology. Our data indicate that (1) tumor cells can influence monocyte-to-MAC differentiation, giving rise to TAM with monocyte-specific phenotypic properties; and (2) this capacity is dependent on the type of tumor cell.     

Supramolecular nanostamping: using DNA as movable type

Here we present a novel printing technique (that we call supramolecular nanostamping), based on the replication of single-stranded DNA features through a hybridization-contact-dehybridization cycle. On a surface containing features each made of single-stranded DNA molecules of known sequence, the complementary DNA molecules are hybridized, spontaneously assembling onto the original pattern due to sequence-specific interactions. These complementary DNA strands, on the end that is assembled far from the original surface, are 5' modified with chemical groups ("sticky ends") that can form bonds with a target surface that is brought into contact. Heating induces dehybridization between DNA strands, leaving the original pattern on the original surface and the copied pattern on the secondary substrate, and thus stamping (see Figure 1). Molecular recognition provides the unique and disruptive ability of transferring large amounts of information in a single printing cycle, that is the simultaneous stamping of spatial information (i.e., the patterns) and of chemical information (i.e., the features' DNA sequence--their chemical composition). This method combines high resolution (<40 nm) with the advantage of an exponential increase in the number of masters; in fact, any printed substrate can be reused as a master. Patterns fabricated via very different lithographic techniques can be replicated.     

Die Eigenschaften von Grünpellets in Abhängigkeit von der Morphologie der Eisenerze

Untersuchung der Morphologie von zwölf türkischen Eisenerzen, von Kiruna- und Venezuelaerz sowie von synthetischen Eisenoxiden und -hydroxiden. Ermittlung der verschiedenen Kristallformen. Messung der Grünfestigkeit von Pellets, die aus den gewählten Erzen hergestellt wurden. Einfluß von Kristallform und spezifischer Oberfläche auf die Pelletfestigkeit. Vergleich der Eigenschaften der synthetischen Proben mit denen natürlicher Erze.     

Primary hyperoxaluria in an adult presenting with end-stage renal failure together with hypercalcemia and hypothyroidism

Primary hyperoxaluria (PH) is a rare genetic disorder characterized by overproduction of oxalate due to specific enzyme deficiencies in glyoxylate metabolism. The primary clinical presentation is in the form of recurrent urolithiasis, progressive nephrocalcinosis, end-stage renal disease, and systemic oxalosis. Herein, we present a case of PH who was diagnosed at 47 years of age after 6 years on hemodialysis. He presented with fatigue, anorexia, weight loss, and was found to have cachexia, diffuse edema, hepatomegaly, ascites, hypercalcemia, hyperphosphatemia, hypoalbuminemia, low parathyroid hormone levels, lytic and resorptive areas in the vertebrae, diffusely increased echogenity of the liver, multiple renal stones, and bilateral nephrocalcinosis. Bone marrow biopsy showed calcium oxalate crystals and crystal granulomas. The liver biopsy could not be performed. The absence of an identifiable reason for secondary forms, the severity of the clinical presentation, and pathological findings led to the diagnosis of PH2. He died while waiting for a potential liver and kidney donor. The presented case is consistent with the literature as he had renal stone disease in the third decade and end-stage renal disease in the fifth decade. Hypercalcemia was thought to be due to osteoclast-stimulating activity of macrophages constituting the granuloma. Erythropoietin-resistant anemia and hypothyroidism were thought to be due to accumulation of oxalate in the bone marrow and thyroid gland, respectively. It is very important to keep in mind the possibility of PH when faced with a patient with nephrocalcinosis and oxalate stone disease.