104 research outputs found

    Controlling the behavior of single live cells with high density arrays of microscopic OLEDs

    Get PDF
    This work was supported in part by the Scottish Funding Council (via SUPA) and the Human Frontier Science Program (HFSP). The authors thank Andrew Morton (U St Andrews) for fruitful discussions.Microarrays of OLEDs are used to ­optically control the locomotion of individual cells in real time. Close contact (<2 μm) between OLEDs and the aqueous cell culture medium is facilitated by high-performance thin-film encapsulation. This work paves the way for using OLED light sources to control and study neuronal activity and cell signaling with extreme spatial and temporal resolution.PostprintPeer reviewe

    Sweet Streams are Made of This: The System Engineer's View on Energy Efficiency in Video Communications

    Full text link
    In recent years, the global use of online video services has increased rapidly. Today, a manifold of applications, such as video streaming, video conferencing, live broadcasting, and social networks, make use of this technology. A recent study found that the development and the success of these services had as a consequence that, nowadays, more than 1% of the global greenhouse-gas emissions are related to online video, with growth rates close to 10% per year. This article reviews the latest findings concerning energy consumption of online video from the system engineer's perspective, where the system engineer is the designer and operator of a typical online video service. We discuss all relevant energy sinks, highlight dependencies with quality-of-service variables as well as video properties, review energy consumption models for different devices from the literature, and aggregate these existing models into a global model for the overall energy consumption of a generic online video service. Analyzing this model and its implications, we find that end-user devices and video encoding have the largest potential for energy savings. Finally, we provide an overview of recent advances in energy efficiency improvement for video streaming and propose future research directions for energy-efficient video streaming services.Comment: 16 pages, 5 figures, accepted for IEEE Circuits and Systems Magazin

    How to Survive Dynamic Pricing Competition in E-commerce

    Get PDF
    ABSTRACT Pricing on e-commerce platforms is highly challenging. Sellers typically i) rival against dozens of competitors, ii) decide on prices for thousands of products, and iii) face steadily changing market situations. With respect to pricing, the challenge is to circumvent the curse of dimensionality to dynamically price products for a given market situation in a timely manner. In this project, we create a stochastic pricing model by analyzing recorded market data. This pricing model can be applied ad-hoc in less than a millisecond per item, allowing us to react immediately to new market situations. Our pricing approach is currently being applied in practice by a large German book seller on Amazon and outperforms the previous rule-based strategy by over 20% with respect to cash-in per book. CCS Concepts •Applied computing → Online shopping; E-commerce infrastructure; Decision analysis; Keywords Dynamic Pricing; Oligopoly Competition; Online Markets; Demand Estimation CHALLENGE Modern market platforms such as Amazon Marketplace or eBay are highly dynamic as sellers can observe the current market situation at any time and adjust their prices instantly. For sellers that handle large inventories, this dynamic is hard to manage as an optimal pricing decision requires handling a multitude of dimensions for each competitor (e.g., price, quality, shipping time, shipping costs, rating). Moreover, financial aspects such as discounting as well as inventory holding costs have to be taken into account. In this project, we partner with adanbo GmbH. adanbo is among the top 10 sellers for used books on Amazon in Germany with an inventory of over 80,000 distinct books (ISBN), each with multiple items (1-20). Our seller can decide -to some extent -on the replenishment of used books (by choosing purchase prices). However, supply is limited and it is not possible to directly reorder specific books. Hence, the challenge is to extract as much profit as pos- Copyright is held by the author(s). sible from a given number of books (inventory level) in a reasonable amount of time. The pricing strategy of our project partner is characterized by a rule-based system that has been developed over the past years by carefully adjusting rules to lessons learned from selling books on Amazon. As our project partner has more than 10 years of experience in the market, we consider his strategy to be effective and accurate. However, market dynamics are increasingly sophisticated making rule-based strategies increasingly hard to handle and maintain. Our goal is to develop a pricing strategy that maximizes expected discounted long-term profits while taking into account the constraints mentioned above. We seek to compute data-driven pricing strategies that are applicable even for large inventories. DATA-DRIVEN PRICING MODEL The project is devoted to revenue managemen

    Two-dimensional Fermi liquids sustain surprising roton-like plasmons beyond the particle-hole band

    No full text
    International audienceUsing inelastic neutron scattering, we have investigated the elementary excitations of an isotropic two-dimensional Fermi liquid, 3He adsorbed on graphite. We provide in this article a detailed account of the principles and methods which allowed measuring for the first time inelastic spectra on a liquid monolayer of 3He, a strong neutron absorber. We also summarise the results presented at this Conference, and review our recent experimental and theoretical work on this this interacting many-body system. At low wave-vectors, near the edge of the particle-hole band, a mode identified as the zero-sound excitation by comparison to our theoretical calculations, is found as predicted at energies much lower than in bulk 3He. The mode enters the particle-hole band, where it undergoes Landau damping. Surprisingly, however, intensity is observed in the neutron spectra at wave-vectors larger than twice the Fermi wavevector. This new branch is interpreted as the high wave-vector continuation of the zero-sound mode, in agreement with the theory. The results open new perspectives in the understanding of the dynamics of correlated fermions

    Intraoperative 3-D mapping of parathyroid adenoma using freehand SPECT

    Full text link
    Background: Freehand single photon emission computed tomography (fSPECT) is a three-dimensional (3-D) tomographic imaging modality based on data acquisition with a handheld detector that is moved freely, in contrast to conventional, gantry-mounted gamma camera systems. In this pilot study, we evaluated the feasibility of fSPECT for intraoperative 3-D mapping in patients with parathyroid adenomas. Methods: Three patients (range 30 to 45 years) diagnosed with hyperparathyroidism (one primary and two tertiary) underwent parathyroid scintigraphy with technetium-99m sestamibi (99mTc-MIBI) to localize parathyroid adenomas. Two patients were referred with persistent hyperparathyroidism after conventional parathyroidectomy. In all three patients, a planar scintigraphy of the neck was performed 10 min after injection (p.i.) followed by SPECT/CT (Symbia T2, Siemens Healthcare) and a correlative ultrasound 2 h p.i. 99mTc-MIBI scan was performed the day before surgery in two patients and at the same day in one patient. fSPECT images were acquired intraoperatively using declipse SPECT (SurgicEyeTM). Results: A total of five parathyroid adenomas were successfully located with SPECT/CT. fSPECT allowed intraoperative detection of all adenomas, and successful parathyroidectomy was accomplished. Parathyroid hormone level decreased intraoperatively in all three patients, on average, by 79% (range 72% to 91%). Conclusion: In this preliminary study, we could demonstrate that intraoperative localization of parathyroid adenomas is feasible using the freehand SPECT technology, thus allowing an image-guided parathyroidectomy

    Entwicklung eines integrierten multifunktionalen Fluoreszenzdetektors

    Get PDF
    Fluoreszenzdetektion hat eine große Bedeutung in biologischen und medizinischen Anwendungen für die Analyse verschiedener Farbstoffe und Zellkulturen. Durch Kombination von Fluidik, Optik und Elektronik ist die Realisierung eines kompakten und hochempfindlichen Messsystems möglich, welches vorteilhaft bei der Messung von Proben mit kleinen Volumina ist

    Thyroid function tests in patients taking thyroid medication in Germany: Results from the population-based Study of Health in Pomerania (SHIP)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Studies from iodine-sufficient areas have shown that a high proportion of patients taking medication for thyroid diseases have thyroid stimulating hormone (TSH) levels outside the reference range. Next to patient compliance, inadequate dosing adjustment resulting in under- and over-treatment of thyroid disease is a major cause of poor therapy outcomes. Using thyroid function tests, we aim to measure the proportions of subjects, who are under- or over-treated with thyroid medication in a previously iodine-deficient area.</p> <p>Findings</p> <p>Data from 266 subjects participating in the population-based Study of Health in Pomerania (SHIP) were analysed. All subjects were taking thyroid medication. Serum TSH levels were measured using immunochemiluminescent procedures. TSH levels of < 0.27 or > 2.15 mIU/L in subjects younger than 50 years and < 0.19 or > 2.09 mIU/L in subjects 50 years and older, were defined as decreased or elevated, according to the established reference range for the specific study area. Our analysis revealed that 56 of 190 (29.5%) subjects treated with thyroxine had TSH levels outside the reference range (10.0% elevated, 19.5% decreased). Of the 31 subjects taking antithyroid drugs, 12 (38.7%) had TSH levels outside the reference range (9.7% elevated, 29.0% decreased). These proportions were lower in the 45 subjects receiving iodine supplementation (2.2% elevated, 8.9% decreased). Among the 3,974 SHIP participants not taking thyroid medication, TSH levels outside the reference range (2.8% elevated, 5.9% decreased) were less frequent.</p> <p>Conclusion</p> <p>In concordance with previous studies in iodine-sufficient areas, our results indicate that a considerable number of patients taking thyroid medication are either under- or over-treated. Improved monitoring of these patients' TSH levels, compared to the local reference range, is recommended.</p

    Genetic Analyses of Heme Oxygenase 1 (HMOX1) in Different Forms of Pancreatitis

    Get PDF
    Contains fulltext : 107993.pdf (publisher's version ) (Open Access)BACKGROUND: Heme oxygenase 1 (HMOX1) is the rate limiting enzyme in heme degradation and a key regulator of inflammatory processes. In animal models the course of pancreatitis was ameliorated by up-regulation of HMOX1 expression. Additionally, carbon monoxide released during heme breakdown inhibited proliferation of pancreatic stellate cells and might thereby prevent the development of chronic pancreatitis (CP). Transcription of HMOX1 in humans is influenced by a GT-repeat located in the promoter. As such, HMOX1 variants might be of importance in the pathogenesis of pancreatitis. METHODS: The GT-repeat and SNP rs2071746 were investigated with fluorescence labelled primers and by melting curve analysis in 285 patients with acute pancreatitis, 208 patients with alcoholic CP, 207 patients with idiopathic/hereditary CP, 147 patients with alcoholic liver cirrhosis, and in 289 controls, respectively. GT-repeat analysis was extended to a total of 446 alcoholic CP patients. In addition, we performed DNA sequencing in 145 patients with alcoholic CP, 138 patients with idiopathic/hereditary CP, 147 patients with alcoholic liver cirrhosis, and 151 controls. Exon 3 screening was extended to additional patients and controls. RESULTS: S- and L-alleles of the GT-repeat, genotypes and alleles of SNP rs2071746 and non-synonymous variants detected by sequencing were found with similar frequencies in all groups. CONCLUSIONS: Although functional data implicate a potential influence of HMOX1 variants on the pathogenesis of pancreatitis, we did not find any association. As rare non-synonymous HMOX1 variants were found in patients and controls, it is rather unlikely that they will have functional consequences essential for pancreatitis development

    A Common Variant of PNPLA3 (p.I148M) Is Not Associated with Alcoholic Chronic Pancreatitis

    Get PDF
    Contains fulltext : 110441.pdf (publisher's version ) (Open Access)BACKGROUND: Chronic pancreatitis (CP) is an inflammatory disease that in some patients leads to exocrine and endocrine dysfunction. In industrialized countries the most common aetiology is chronic alcohol abuse. Descriptions of associated genetic alterations in alcoholic CP are rare. However, a common PNPLA3 variant (p.I148M) is associated with the development of alcoholic liver cirrhosis (ALC). Since, alcoholic CP and ALC share the same aetiology PNPLA3 variant (p.I148M) possibly influences the development of alcoholic CP. METHODS: Using melting curve analysis we genotyped the variant in 1510 patients with pancreatitis or liver disease (961 German and Dutch alcoholic CP patients, 414 German patients with idiopathic or hereditary CP, and 135 patients with ALC). In addition, we included in total 2781 healthy controls in the study. RESULTS: The previously published overrepresentation of GG-genotype was replicated in our cohort of ALC (p-value <0.0001, OR 2.3, 95% CI 1.6-3.3). Distributions of genotype and allele frequencies of the p.I148M variant were comparable in patients with alcoholic CP, idiopathic and hereditary CP and in healthy controls. CONCLUSIONS: The absence of an association of PNPLA3 p.I148M with alcoholic CP seems not to point to a common pathway in the development of alcoholic CP and alcoholic liver cirrhosis
    corecore