julilili42/papers huggingface dataset:
Parabolic mirror‐assisted tip‐enhanced spectroscopic imaging for non‐transparent materials
2009-09-01

Abstract A versatile and efficient tip‐enhanced spectroscopic imaging technique based on a parabolic mirror (PM) assisted near‐field optical microscope is demonstrated. The replacement of the conventional objective lens with a parabolic mirror allows the non‐restricted investigation of sample materials regarding their opacity. In addition, an improved signal collection efficiency and effective excitation of the longitudinal plasmonic oscillation in the tip apex are obtained. The capabilities of PM‐assisted tip‐enhanced Raman (TER) and photoluminescence (PL) imaging in distinguishing the individual domains made of different chemical components in poly (3‐hexythiophene)/[6, 6]‐penyl‐C 61 butyric acid methyl ester (P3HT/PCBM) solar cell blend film and in the investigation of the plasmonic properties of geometrically well‐defined Au cones are demonstrated. Copyright © 2009 John Wiley &amp; Sons, Ltd.
In vitro Myogenic Differentiation of Human Bone Marrow–Derived Mesenchymal Stem Cells as a Potential Treatment for Urethral Sphincter Muscle Repair
2009-09-01

To explore a new treatment strategy for urinary incontinence, human bone marrow mesenchymal stem cells (MSC) of the first in vitro passage were exposed to 5‐azacytidine (AZA) to induce myogenic differentiation, and cultured for a total of six passages. Expression of stem cell surface antigens and intracellular α‐actin was examined by flow cytometry at the end of each passage and compared to that of native MSC (not exposed to AZA) cultured in parallel. To analyze differentiation into striated muscle, expression of the transcription factor MyoD1 and myosin heavy chain (MyHC) was examined by RT‐PCR. Both native and AZA‐exposed MSC of all passages were negative for the progenitor/endothelial antigen CD34, leukocytic CD45, and endothelial/monocytic CD31. In contrast, the MSC markers CD73, CD90, CD105, and intracellular actin were detected in both groups of MSC throughout the culture period. After an initial increase, the expression level of MSC antigens decreased over time particularly in AZA‐exposed MSC. Expression of smooth muscle α‐actin also declined, but was greater in AZA‐exposed MSC throughout the culture period. Varying percentages of MSC cultures expressed MyoD1 and MyHC mRNA. In late passages, AZA‐exposed MSC tended to be more frequently positive than native MSC. In pilot experiments, transplantation of MSC into the bladder neck tissue of athymic rats was feasible; long‐term analyses are pending. We conclude that independent of AZA exposure, MSC express smooth and striated muscle antigens. Treatment with AZA slightly increases myogenic differentiation, but may not be necessary in future studies of MSC as a treatment modality for urinary incontinence.
Functional Heterogeneity of the Bone Marrow Vascular Niche
2009-09-01

Sinusoidal endothelial cells (SECs) comprise the platform where trafficking into and out of the BM occurs and where hematopoietic stem and progenitor cells (HSPC) harbor and receive cues for self‐renewal, survival, and differentiation. Therefore, SECs are referred to as a bone marrow vascular niche (BMVN). Hematopoietic regeneration has been shown to occur only with concurrent angiogenic regeneration. However, there are still not sufficient means to identify and isolate SECs, therefore the “niche endothelial cell” remains incompletely characterized. VEGF‐receptor‐3 (VEGFR3) is expressed exclusively by the SECs, while Sca1 and Tie2 are only expressed on the VEGFR3 − arteriolar endothelium. We previously demonstrated the importance of vascular recovery in hematopoietic regeneration from myelosuppression due to cytotoxic agents or whole‐body irradiation. Therefore to establish the functional importance of SECs, the mechanisms underlying BMVN regeneration were examined utilizing a 5‐fluorouracil (5‐FU) myelosuppression model of vascular damage. Injection of antibodies against murine VEGFR‐1 and ‐2 had no significant effect on hemangiogenic recovery. However, when soluble VEGFR‐1, a decoy receptor for VEGF‐A and PlGF, was injected after 5‐FU, both angiogenic remodeling and regeneration of megakaryopoiesis were delayed. In conclusion, we show that the bone marrow vasculature comprises heterogeneous compartments. SECs are distinguished from arterioles by unique immunophenotypes. Regeneration of damaged SECs is the rate‐limiting step in hematopoietic regeneration from myelosuppressive therapy. Novel, high‐efficiency VEGF‐binding drugs in combination with chemotherapeutic agents may lead to cases of prolonged cytopenia.
Adaptive rule based fetal QRS complex detection using hilbert transform
2009-09-01

In this paper we introduce an adaptive rule based QRS detection algorithm using the Hilbert transform (adHQRS) for fetal magnetocardiography processing. Hilbert transform is used to combine multiple channel measurements and the adaptive rule based decision process is used to eliminate spurious beats. The algorithm has been tested with a large number of datasets and promising results were obtained.
Experiences with a gravity-assisted valve in hydrocephalic children
2009-09-01

Object Over the past decade, a gravity-assisted valve (GAV) has become a standard device in many European pediatric hydrocephalus centers. Because past comparative clinical outcome studies on valve design have not included any GAV, the authors in this trial evaluated the early results of GAV applications in a pediatric population. Methods For a minimum of 2 years the authors monitored 169 of 182 hydrocephalic children who received a pediatric GAV at their first CSF shunt insertion (61.5%) or as a substitute for any differential pressure valve (38.5%) at 1 of 7 European pediatric hydrocephalus centers. Outcomes were categorized as valve survival (primary outcome) or shunt survival (secondary outcome). The end point was defined as valve explantation. Results Within a follow-up period of 2 years, the valve remained functional in 130 (76.9%) of 169 patients. One hundred eight of these patients (63.9%) had an uncomplicated clinical course without any subsequent surgery, and 22 (13%) were submitted to a valve-preserving catheter revision without any further complications during the follow-up period. Thirty-nine patients (23.1%) reached an end point of valve explantation: 13 valve failures from infection (7.7%), 8 (4.7%) from overdrainage, and 18 (10.6%) from underdrainage. Conclusions Compared with nongravitational shunt designs, a GAV does not substantially affect the early complication rate. Valve-preserving shunt revisions do not increase the risk of subsequent valve failure and therefore should not be defined as an end point in studies on valve design. A significant impact of any well-established valve design on the early complication rate in shunt surgery is not supported by any current data; therefore, this correlation should be dismissed. As overdrainage-related complications have been shown to occur late, the presumed advantages of a pediatric GAV remain to be shown in a long-term study.
Evolving driving controllers using Genetic Programming
2009-09-01

Computational gaming requires the automatic generation of virtual opponents for different game levels. We have turned to artificial evolution to automatically generate such game players. In particular, we have used Genetic Programming to automatically evolve computer programs for computer gaming. With Genetic Programming, in theory, it is possible to generate any kind of program. The programs are not constrained as much as they are in other computational learning approaches, e.g. neural networks. We show how Genetic Programming improved upon a manually crafted race car driver (proportional controller). The open race car simulator TORCS was used to evaluate the virtual drivers.
Generic Self-Adaptation to Reduce Design Effort for System-on-Chip
2009-09-01

We investigate a generic self-adaptation method to reduce the design effort for system-on-chip (SoC). Previous self-adaptation solutions at chip-level use circuitries which have been specially designed for the current problem by hand, leading to an elaborate and inflexible design process, requiring specially trained engineers, and making design reuse difficult. On the other hand, a generic self-adaptation method that can be used for various self-adaptation problems promises to reduce the necessary design effort, but may come with reduced performance and other costs. In this paper, we analyze the performance, self-adaptation capabilities and costs of a generic self-adaptation method. The proposed method allows chip-level self-adaptation of a SoC, can tolerate unforeseen events, and can generalize from previous self-adaptation tasks. Furthermore, the method helps to improve the design process by allowing design reuse, providing generic applicability, and offering a uniform design process for various self-adaptation tasks. Simulation results show that the performance of our method lies only 10% below the performance of a perfect, non-adaptive system in the average case, and only 32% in the worst case. In case of unforeseen events, where the performance of a non-adaptive system decreases significantly, the method can keep its performance level by self-adaptation. We also compare other costs involved.
Influence of Material Properties on Hydrogen Sensing for SnO2 Nanomaterials
2009-09-01

Two SnO2 materials synthesized from SnCl4 and Sn(CH3COO)2 precursors were investigated concerning their hydrogen sensing properties in different oxygen backgrounds. At very low oxygen concentrations one observes a huge increase in the sensor response but no water formation in the exhaust and very different sensing performance for the different materials. As the oxygen content increases, the sensor response decreases and water production occurs and the sensing performance of the two materials becomes very similar.
Disease Models from Pluripotent Stem Cells
2009-09-01

Murine models of congenital and acquired diseases are invaluable yet often do not faithfully mirror human pathophysiology. Embryonic stem (ES) cells differentiated in vitro recapitulate aspects of early embryogenesis and differentiate into multiple somatic tissues, thereby serving as a powerful platform for developmental studies in the human. Analysis of genetically modified ES cells (by lentiviral gene transduction or derivation from embryos carrying genetic diseases, for example) offers the unprecedented opportunity to study in detail disease initiation and progression during embryonic development. ES cells and induced pluripotent stem (iPS) cells obtained by somatic cell reprogramming from patients affected by various disorders promise unique insights into the gradual pathogenesis of disease, moreover enabling development of customized cellular therapies by in vitro gene correction in autologous cells.
PBIL PDR for scalable Bluetooth Indoor Localization
2009-09-01

The ever-existing problems in indoor localization are attaining efficient scalability, reliability and accuracy besides cost efficiency. Although diverse approaches based on WLAN, Bluetooth, ZigBee, RFID and UWB had been divulged for localization and navigation, these schemes often do lack competent localization. Furthermore these schemes linger either expensive or be deficient in accuracy. Moreover not all technologies exist in smart phones. Recent outburst of technology expansion has paved way to solve indoor localization complexity by cohering various positioning methods and sensor models. In this paper, we developed a unified particle filter based localization approach based on Bluetooth positioning and pedestrian dead reckoning (PDR) method. We call this system as PBIL (PDR for scalable Bluetooth Indoor Localization). The proposed approach overcomes failure in the context of uninterrupted service where Bluetooth technologies lag behind. By coalescing Bluetooth and 3D compass sensor models, we surmount the localizing tribulations and guarantee a preeminent solution for pedestrian indoor localization and navigation.
Duality and Asymptotics for a Class of Nonneutral Discrete Moran Models
2009-09-01

A Markov chain X with finite state space {0,..., N } and tridiagonal transition matrix is considered, where transitions from i to i -1 occur with probability ( i / N )(1- p (i/ N )) and transitions from i to i +1 occur with probability (1- i / N ) p ( i / N ). Here p :[0,1]→[0,1] is a given function. It is shown that if p is continuous with p ( x )≤ p (1) for all x ∈[0,1] then, for each N , a dual process Y to X (with respect to a specific duality function) exists if and only if 1- p is completely monotone with p (0)=0. A probabilistic interpretation of Y in terms of an ancestral process of a mixed multitype Moran model with a random number of types is presented. It is shown that, under weak conditions on p , the process Y , properly time and space scaled, converges to an Ornstein–Uhlenbeck process as N tends to ∞. The asymptotics of the stationary distribution of Y is studied as N tends to ∞. Examples are presented involving selection mechanisms. results.
CO2 sensing with chemoresistive Nd2O2CO3 sensors - Operando insights
2009-09-01

In this work the sensing of Nd2O2CO3-based chemoresistive CO2 sensor was investigated combining DRIFT and DC-resistance measurements. Besides the already reported effect of CO2 exposure, we found that exposure to CO determines comparable effects and that the presence of oxygen in the background is not important. The humidity significantly influences the response for both gases. The spectroscopic results reveal that the exposure to both CO and CO2 consumes the water-related surface species – the rooted-hydroxyls being the electrically active one – and increases the concentration of carbonates; the decrease of the rooted-hydroxyls is probably the cause of the resistance increase.
INR Indoor Navigator with RFID Locator
2009-09-01

In recent years there is a growing necessity for indoor location based services. One such indoor location based service is pedestrian navigation. A handful of solutions had been employed to achieve pedestrian navigation. However these solutions that are available in market either remained unreliable or highly expensive. The key criterion to achieve reliable navigation lies in instant and accurate localization of the user. In this article, we present a prototype system for pedestrian navigation for indoors. We executed a probabilistic method based on RFID tag count and RSSI to localize the user and in addition we developed a route planning algorithm to achieve complete navigation. The route planning algorithm takes personal conditions of the pedestrian into account. Overall, our experimental results validate the reliability and competence of the proposed system.
Instance Sampling Methods for Pronoun Resolution
2009-09-01

Instance sampling is a method to balance extremely skewed training sets as they occur, for example, in machine learning settings for anaphora resolution. Here, the number of negative samples (i.e. non-anaphoric pairs) is usually substantially larger than the number of positive samples. This causes classifiers to be biased towards negative classification, leading to suboptimal performance. In this paper, we explore how dierent techniques of instance sampling influence the performance of an anaphora resolution system for German given dierent classifiers. All sampling methods prove to increase the F-score for all classifiers, but the most successful method is random sampling. In the best setting, the F-score improves from 0.541 to 0.608 for memory-based learning, from 0.561 to 0.611 for decision tree learning and from 0.511 to 0.584 for maximum entropy learning.
INVERSION BY DEFINITIONAL REFLECTION AND THE ADMISSIBILITY OF LOGICAL RULES
2009-09-01

The inversion principle for logical rules expresses a relationship between introduction and elimination rules for logical constants. Hallnäs &amp; Schroeder-Heister (1990, 1991) proposed the principle of definitional reflection , which embodies basic ideas of inversion in the more general context of clausal definitions. For the context of admissibility statements, this has been further elaborated by Schroeder-Heister (2007). Using the framework of definitional reflection and its admissibility interpretation, we show that, in the sequent calculus of minimal propositional logic, the left introduction rules are admissible when the right introduction rules are taken as the definitions of the logical constants and vice versa. This generalizes the well-known relationship between introduction and elimination rules in natural deduction to the framework of the sequent calculus.
Physiological significance of SK4 channels in pancreatic β-cell oscillations
2009-09-01

Pancreatic beta-cells show oscillations in membrane potential (Vm), the cytosolic Ca (2+) concentration ([Ca (2+) ]c) and finally insulin secretion. It is well accepted that the initiation of a burst phase with action potentials is mediated by voltage-dependent Ca (2+) (and Na (+) ) channels. The mechanism triggering the onset of interburst phases is less clear. The exact nature of the K (+) channels that hyperpolarize Vm to maintain the rhythmic activity is unknown. In 1999 Göpel and co-workers (1) described a current termed Kslow and claimed that this current terminates the burst phases. KATP current is a part of the Kslow current. We could show that the Ca (2+) -dependent K (+) current through K (+) channels of intermediate conductance (SK4, KCa3.1 or IK1) also contributes to the Kslow current. We suggest that the Kslow current is composed of two currents through metabolism-regulated K (+) channels, KATP (regulated by ATP) and SK4 (regulated by Ca (2+) ). We further propose that the SK4 component of the Kslow current can trigger oscillations in mice without functioning KATP channels.
Electronic subretinal implants allow blind retinitis pigmentosa patients to read letters and recognize the direction of fine stripe patterns
2009-09-01

Abstract Purpose Restoration of letter reading and stripe pattern recognition in blind RP patients by placing subretinal implants transchoroidally near the macula, consisting of two arrays: 4x4 electrodes controlled retroauricularly via a subdermal line for direct stimulation (“DS array”) and a "chip" (3x3x0,1 mm),1500 electrodes. Methods Letters and stripe pattern were presented to 3 patients via the light sensitive chip – by patterns steadily presented at a screen. On the DS array the sensation evoked by each individual pulse consists of whitish round dot, clearly separated from its neighbor. Patterns consisting of such 4 x 4 dots correspond to letters of approximately 5 cm diameter presented at 60 cm distance. Results Pat.1 correctly (20/24) recognized the direction of the letter “U”, presented with the opening in four different directions (DS array). Pat.2 correctly (12/12) differentiated letters via DS array (e.g. COIL). With the light sensitive chip, he correctly (22/24) differentiated letters (e.g. LITZ; 8,5 cm high, 1.7 cm line width) steadily presented on a screen at 62 cm distance Pat.3 recognized (15/20 correct, 4AFC) the direction of lines or stripe patterns with the chip, as did Pat.1 (11/14, 2AFC) and Pat.2 (11/12 4AFC) up to 0.35 cycles/deg. Conclusion Active subretinal multielectrode implants with currents close to produce retinotopically correct patterns that allow for the first time recognition of individual letters and stripe patterns up to 0.35 cycles/deg clearly supporting the feasibility of light sensitive subretinal multi‐electrode devices for restoration of useful vision.
Microsystem Technology for Ambient Assisted Living (AAL)
2009-09-01

Abstract AAL is certainly an application area with sensor as well as actuator needs. Some of the requirements can be fulfilled by state of the art technology; some areas however still need a lot of RD the other domain is fall detection. For both application areas one has to understand both the state of the art and the drawbacks of the current solutions. One can state clearly that there is a huge potential for the development of new microsystems. Still one has to keep in mind that usage in elderly homes also requires consent and cooperation of the users which is the focus of the user centered design principle.
Barriers to internationalization: Firm-level evidence from Germany
2009-09-01

Exporters and multinationals are larger and more productive than their domestic counterparts. In addition to productivity, financial constraints and labor market constraints might constitute barriers to entry into foreign markets. We present new empirical evidence on the extensive and intensive margin of exports and FDI based on detailed micro-level data of German firms. Our paper has three main findings. First, in line with earlier literature, we find a positive impact of firm size and productivity on firms’ international activities. Second, small firms suffer more frequently from financial constraints than bigger firms, but financial conditions have no strong effect on internationalization. Third, labor market constraints constitute a more severe barrier to foreign activities than financial constraints. Being covered by collective bargaining particularly impedes international activities.
Openness and Growth: The Long Shadow of the Berlin Wall
2009-09-01

The question whether international openness causes higher domestic growth has been subject to intense discussions in the empirical growth literature. This paper addresses this issue using the fall of the Berlin wall in 1990 as a natural experiment. We analyze whether the slow-down in convergence in per capita income between East and West Germany since the mid-1990s and the lower international openness of East Germany are linked. We address the endogeneity of openness by adapting the methodology proposed by Frankel and Romer (1999) in a panel framework. We instrument openness with time-invariant exogenous geographic variables and time-varying exogenous policy variables. We also distinguish different channels of integration. Our paper has three main findings. First, geographic variables have a significant impact on regional openness. Second, controlling for geography, East German states are less integrated into international markets along all dimensions of integration considered. Third, the degree of openness for trade has a positive impact on regional income per capita.
Localizing the neonatal and fetal spontaneous brain activity by hilbert phase analysis
2009-09-01

We propose a novel method to characterize the spontaneous brain signals using Hilbert phases. The Hilbert phase of a signal exhibits phase slips when the magnitude of the successive phase difference exceeds pi. To this end we use standard deviation (sigmaDeltatau) of the time (Deltatau) between successive phase slips to characterize the signals. We demonstrate the application of this approach to neonatal and fetal magnetoencephalographic signals recorded using a 151-sensor array to identify the sensors containing the neonatal and fetal brain signals. To this end we propose a spatial filter using sigma(Deltatau) as weights to reconstruct the brain signals.
Emergence of exponentially small reflected waves
2009-09-01

We study the time-dependent scattering of a quantum mechanical wave packet at a barrier for energies larger than the barrier height, in the semi-classical regime. More precisely, we are interested in the leading order of the exponentially small scattered part of the wave packet in the semiclassical parameter when the energy density of the incident wave is sharply peaked around some value. We prove that this reflected part has, to leading order, a Gaussian shape centered on the classical trajectory for all times soon after its birth time. We give explicit formulas and rigorous error bounds for the reflected wave for all of these times.