Modelling of Optical Detection of Spin-Polarized Carrier Injection into Light-Emitting Devices

We investigate the emission of multimodal polarized light from Light Emitting Devices due to spin-aligned carriers injection. The results are derived through operator Langevin equations, which include thermal and carrier-injection fluctuations, as well as non-radiative recombination and electronic g-factor temperature dependence. We study the dynamics of the optoelectronic processes and show how the temperature-dependent g-factor and magnetic field affect the polarization degree of the emitted light. In addition, at high temperatures, thermal fluctuation reduces the efficiency of the optoelectronic detection method for measuring spin-polarization degree of carrier injection into non-magnetic semicondutors.Comment: 15 pages, 7 figures, replaced by revised version. To appear in Phys. Rev.

Finding the Most Similar Concepts in Two Different Ontologies

Abstract. A concise manner to send information from agent A to B is to use phrases constructed with the concepts of A: to use the concepts as the atomic tokens to be transmitted. Unfortunately, tokens from A are not understood by (they do not map into) the ontology of B, since in general each ontology has its own address space. Instead, A and B need to use a common communication language, such as English: the transmission tokens are English words. An algorithm is presented that finds the concept cB in OB (the ontology of B) most closely resembling a given concept cA. That is, given a concept from ontology OA, a method is provided to find the most similar concept in OB, as well as the similarity sim between both concepts. Examples are given. 1 Introduction an

The disulphide isomerase DsbC cooperates with the oxidase DsbA in a DsbD-independent manner

In Escherichia coli , DsbA introduces disulphide bonds into secreted proteins. DsbA is recycled by DsbB, which generates disulphides from quinone reduction. DsbA is not known to have any proofreading activity and can form incorrect disulphides in proteins with multiple cysteines. These incorrect disulphides are thought to be corrected by a protein disulphide isomerase, DsbC, which is kept in the reduced and active configuration by DsbD. The DsbC/DsbD isomerization pathway is considered to be isolated from the DsbA/DsbB pathway. We show that the DsbC and DsbA pathways are more intimately connected than previously thought. dsbA - dsbC - mutants have a number of phenotypes not exhibited by either dsbA - , dsbC - or dsbA - dsbD - mutations: they exhibit an increased permeability of the outer membrane, are resistant to the lambdoid phage φ80, and are unable to assemble the maltoporin LamB. Using differential two-dimensional liquid chromatographic tandem mass spectrometry/mass spectrometry analysis, we estimated the abundance of about 130 secreted proteins in various dsb - strains. dsbA - dsbC - mutants exhibit unique changes at the protein level that are not exhibited by dsbA - dsbD - mutants. Our data indicate that DsbC can assist DsbA in a DsbD-independent manner to oxidatively fold envelope proteins. The view that DsbC's function is limited to the disulphide isomerization pathway should therefore be reinterpreted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72894/1/MMI_6030_sm_Tables_S1-S4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/72894/2/MMI_tables_s1-s4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/72894/3/j.1365-2958.2007.06030.x.pd

Ribosomally synthesized and post-translationally modified peptide natural products: Overview and recommendations for a universal nomenclature

Covering: 1988 to 2012 This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed

Evaluating the temperature dependence of heat-transfer based detection:A case study with caffeine and Molecularly Imprinted Polymers as synthetic receptors

Molecularly Imprinted Polymers (MIPs) are synthesized for the selective detection of caffeine. The polymerization process, monomer and crosslinker monomer composition are varied to determine the optimal synthesis procedure via batch rebinding experiments evaluated with optical detection. The selectivity is tested by comparing the response of caffeine to compounds with similar chemical structures (theophylline and theobromine) and dopamine, another neurotransmitter. Subsequently, the MIP polymer particles are integrated into bulk modified MIP screen-printed electrodes (MIP-modified SPEs). The sensors are used to measure caffeine content in various samples employing the Heat-Transfer Method (HTM), a low-cost and simple thermal detection method that is based on differences in thermal resistance at the solid-liquid interface. At first, the noise is minimized by adjusting the settings of temperature feedback loop. Second, the response of the MIP-modified SPE is studied at various temperatures ranging from 37 to 50 and 85 °C. The binding to MIP-modified SPEs has never been studied at elevated temperatures since most biomolecules are not stable at those temperatures. Using caffeine as proof-of-concept, it is demonstrated that at 85 °C the detection limit is significantly enhanced due to higher signal to noise ratios and enhanced diffusion of the biomolecule. Thermal wave transport analysis (TWTA) is also optimized at 85 °C producing a limit of detection of ∼1 nM. Next, MIP-modified SPEs are used to measure the caffeine concentration in complex samples including caffeinated beverages, spiked tap water and waste water samples.The use of MIP-modified SPEs combined with thermal detection provides sensors that can be used for fast and low-cost detection performed on-site, which holds great potential for the determination of contaminants in environmental samples. The platform is generic and by adapting the MIP layer, we can expand to this a range of relevant targets

Improving text mining with controlled natural language: a case study for protein interactions

Linking the biomedical literature to other data resources is notoriously difficult and requires text mining. Text mining aims to automatically extract facts from literature. Since authors write in natural language, text mining is a great natural language processing challenge, which is far from being solved. We propose an alternative: If authors and editors summarize the main facts in a controlled natural language, text mining will become easier and more powerful. To demonstrate this approach, we use the language Attempto Controlled English (ACE). We define a simple model to capture the main aspects of protein interactions. To evaluate our approach, we collected a dataset of 459 paragraph headings about protein interaction from literature. 56% of these headings can be represented exactly in ACE and another 23% partially. These results indicate that our approach is feasible

Design of a stable cyclic peptide analgesic derived from sunflower seeds that targets the kappa-opioid receptor for the treatment of chronic abdominal pain

The rising opioid crisis has become a worldwide societal and public health burden, resulting from the abuse of prescription opioids. Targeting the κ-opioid receptor (KOR) in the periphery has emerged as a powerful approach to develop novel pain medications without central side effects. Inspired by the traditional use of sunflower (Helianthus annuus) preparations for analgesic purposes, we developed novel stabilized KOR ligands (termed as helianorphins) by incorporating different dynorphin A sequence fragments into a cyclic sunflower peptide scaffold. As a result, helianorphin-19 selectively bound to and fully activated the KOR with nanomolar potency. Importantly, helianorphin-19 exhibited strong KOR-specific peripheral analgesic activity in a mouse model of chronic visceral pain, without inducing unwanted central effects on motor coordination/sedation. Our study provides a proof of principle that cyclic peptides from plants may be used as templates to develop potent and stable peptide analgesics applicable via enteric administration by targeting the peripheral KOR for the treatment of chronic abdominal pain.Edin Muratspahic, Nataša Tomaševic, Johannes Koehbach, Leopold Duerrauer, Seid Hadžić, Joel Castro ... et al

Representing and Validating Digital Business Processes

The success of the semantic web relies heavily on ontologies. However, using ontologies for this specific area poses a number of new problems. One of these problems, extracting a high quality ontology from a given base ontology, is currently receiving increasing attention. Areas such as versioning, distribution and maintenance of ontologies often involve this problem. Here, a formalism is presented that enables grouping ontology extraction requirements into different categories, called optimization schemes. These optimization schemes provide a way to introduce quality in the extraction process. An overview of the formalism is discussed, as well as a demonstration of several example optimization schemes. Each of these optimization schemes meets a certain requirement, and consists of rules and algorithms. Examples of how the formalism is deployed to reach a high-quality result, called a materialized ontology view, are covered. The presented methodology provides a foundation for further developments, and shows the possibility of obtaining usable ontologies in a highly automated way