bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolic response of Alicycliphilus denitrificans strain BC toward electron acceptor variation
Authors: Oosterkamp Margreet J. , Boeren Sjef , Plugge Caroline M. , Schaap Peter J. , Stams Alfons J. M.
Published: August 2013

Alicycliphilus denitrificans is a versatile, ubiquitous, facultative anaerobic bacterium. Alicycliphilus denitrificans strain BC can use chlorate, nitrate, and oxygen as electron acceptor for growth. Cells display a prolonged lag‐phase when transferred from nitrate to chlorate and vice versa. Furthermore, cells adapted to aerobic growth do not easily use nitrate or chlorate as electron acceptor. We further investigated these responses of strain BC by differential proteomics, transcript analysis, and enzyme activity assays. In nitrate‐adapted cells transferred to chlorate and vice versa, appropriate electron acceptor reduction pathways need to be activated. In oxygen‐adapted cells, adaptation to the use of chlorate or nitrate is likely difficult due to the poorly active nitrate reduction pathway and low active chlorate reduction pathway. We deduce that the Nar‐type nitrate reductase of strain BC also reduces chlorate, which may result in toxic levels of chlorite if cells are transferred to chlorate. Furthermore, the activities of nitrate reductase and nitrite reductase appear to be not balanced when oxygen‐adapted cells are shifted to nitrate as electron acceptor, leading to the production of a toxic amount of nitrite. These data suggest that strain BC encounters metabolic challenges in environments with fluctuations in the availability of electron acceptors. All MS data have been deposited in the ProteomeXchange with identifier PXD000258.
Determinants of suicidal ideation in patients with breast cancer
Authors: Kim Jae‐Min , Jang Ji‐Eun , Stewart Robert , Kim Seon‐Young , Kim Sung‐Wan , Kang Hee‐Ju , Shin Il‐Seon , Park Min‐Ho , Yoon Jung‐Han , Yoon Jin‐Sang
Published: August 2013

Background

Breast cancer survivors are at higher risk of psychological problems including suicidal ideation. However, studies on suicidal ideation in breast cancer survivors have been rare and have not been investigated prospectively. This study aimed to investigate the prevalence and independent risk factors for suicidal ideation within 1 week and at 1 year after breast surgery for breast cancer.

Methods

A total of 284 patients with breast cancer were evaluated within 1 week after breast surgery, and 244 (84%) were followed up 1 year later. Suicidal ideation was ascertained using the item ‘suicidal thoughts’ from the Beck Depression Inventory. Various factors potentially related to suicidal ideation were evaluated including sociodemographic and clinical characteristics, and genetic polymorphisms on serotonin and brain‐derived neurotrophic factor (BDNF) systems.

Results

Suicidal ideation was present in 10.9% of participants at 1 week and 11.4% at 1 year after breast surgery. Suicidal ideation was independently associated with depression and physical disability at 1 week and with living alone, anxiety, advanced cancer stage, and the BDNF met allele (but not with genetic polymorphisms on serotonergic system) at 1 year after breast surgery.

Conclusions

Suicidal ideation was common and had similar prevalences in both short‐term and longer‐term follow‐ups after breast cancer. However, associated factors were substantially different between the two evaluation points, which suggest that time‐specific programs may be needed for identifying and managing suicidal risk in patients with breast cancer. Copyright © 2013 John Wiley & Sons, Ltd.
Cool horizons for entangled black holes
Authors: Maldacena J. , Susskind L.
Published: August 2013

General relativity contains solutions in which two distant black holes are connected through the interior via a wormhole, or Einstein‐Rosen bridge. These solutions can be interpreted as maximally entangled states of two black holes that form a complex EPR pair. We suggest that similar bridges might be present for more general entangled states. In the case of entangled black holes one can formulate versions of the AMPS(S) paradoxes and resolve them. This suggests possible resolutions of the firewall paradoxes for more general situations.
Thermal deactivation of lifetime‐ limiting grown‐in point defects in n‐type Czochralski silicon wafers
Authors: Rougieux F. E. , Grant N. E. , Macdonald D.
Published: August 2013

In this study, we uncover a recombination‐active grown‐in defect reducing the minority carrier lifetime of Czochralski grown n‐type silicon from 5 ms to below 2 ms. We also demonstrate that the defect can be de‐activated by annealing between 300 °C and 360 °C. Our experimental findings suggest that vacancy‐related pairs incorporated during ingot growth may be responsible for the decreased minority carrier lifetime. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Co‐diffusion from solid sources for bifacial n‐type solar cells
Authors: Rothhardt Philip , Keding Roman , Wolf Andreas , Biro Daniel
Published: August 2013

We present a simplified process sequence for the fabrication of large area n‐type silicon solar cells. The boron emitter and full area phosphorus back surface field are formed in one single high temperature step using doped glasses deposited by plasma enhanced chemical vapour deposition (PECVD) as diffusion sources. By optimizing the gas composition during the PECVD process, we not only prevent the formation of a boron rich layer (BRL), but also achieve doping profiles that exhibit a low dark saturation current density while allowing for contact formation by screen printing. The presented co‐diffusion process allows for major process simplification compared to the state of the art diffusion process relying on multiple high temperature processes, masking and wet chemistry steps.

magnified image

Solar cell based on n‐type silicon featuring a co‐diffused boron emitter and phosphorus back‐surface field (BSF).

(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combined control with sliding mode and partial feedback linearization for 3D overhead cranes
Authors: Tuan Le Anh , Lee Soon‐Geul , Ko Deok Hyeon , Nho Luong Cong
Published: August 2013

A 3D overhead crane is an underactuated system consisting of five outputs: trolley position, bridge translation, cable length, and two cargo swings. These outputs are controlled by three actuators for cargo hoisting, trolley motion, and bridge traveling. This study proposes the use of a nonlinear controller that performs five tasks concurrently: cargo hoisting, trolley tracking, bridge motion, payload vibration suppression during transport, and cargo swing elimination at the destination. The proposed algorithm is combined with two control components: (i) partial feedback linearization, which is a precursor to controller design, to suppress cargo vibration; and (ii) sliding mode method, which provides robust control in lifting the payload and driving trolley and bridge motions against model imprecision and uncertainty. These two control mechanisms are successfully merged into a combined controller because the kinematic relationships between the state variables are made apparent in the system dynamics. Simulation and experimental results show that the proposed controller asymptotically stabilizes all system responses.Copyright © 2013 John Wiley & Sons, Ltd.
Peanut Leaf Inspired Multifunctional Surfaces
Authors: Yang Shuai , Ju Jie , Qiu Yuchen , He Yaxu , Wang Xiaolin , Dou Shixue , Liu Kesong , Jiang Lei
Published: August 2013

Nature has long served as a source of inspiration for scientists and engineers to design and construct multifunctional artificial materials. The lotus and the peanut are two typical plants living in the aquatic and the arid (or semiarid) habitats, respectively, which have evolved different optimized solutions to survive. For the lotus leaf, an air layer is formed between its surface and water, exhibiting a discontinuous three‐phase contact line, which resulted in the low adhesive superhydrophobic self‐cleaning effect to avoid the leaf decomposition. In contrast to the lotus leaf, the peanut leaf shows high‐adhesive superhydrophobicity, arising from the formation of the quasi‐continuous and discontinuous three‐phase contact line at the microscale and nanoscale, respectively, which provides a new avenue for the fabrication of high adhesive superhydrophobic materials. Further, this high adhesive and superhydrophobic peanut leaf is proved to be efficient in fog capture. Inspired by the peanut leaf, multifunctional surfaces with structural similarity to the natural peanut leaf are prepared, exhibiting simultaneous superhydrophobicity and high adhesion towards water.
“Non‐coercive Rearrangements”: Theorizing Desire in TESOL
Authors: Motha Suhanthie , Lin Angel
Published: August 2013

In this article, the authors argue that at the center of every English language learning moment lies desire: desire for the language; for the identities that English represents; for capital, power, and images that are associated with English; for what is believed to lie beyond the doors that English unlocks. However, despite its centrality within TESOL practice, the construct of desire has been largely undertheorized by English language educators. The authors propose (1) that educators in the TESOL field would benefit from a greater recognition of desire as situated and co‐constructed, acknowledging that our desires are not solely our own but are intersubjectively constituted and shaped by our social, historical, political, institutional, and economic contexts; (2) that the difference between conscious and unconscious desire is significant in language learning; and (3) that whereas desire can be manipulated in exploitative or unethical ways, it can also, given the right circumstances, serve as a tool for compassionate and liberatory pedagogy. This article explores the interconnectedness of desire with motivation and investment, the commodification of English, akogare desire, racial identities, globalizing forces, colonialism, and communicative language teaching. The authors propose a revisioning of TESOL that recognizes the centrality of desire in the acquisition of English.
Effectiveness of phages in the decontamination of Listeria monocytogenes adhered to clean stainless steel, stainless steel coated with fish protein, and as a biofilm
Authors: Ganegama Arachchi Geevika J , Cridge Andrew G , Dias-Wanigasekera Beatrice M , Cruz Cristina D , McIntyre Lynn , Liu Rachel , Flint Steve H , Mutukumira Anthony N
Published: August 2013

Listeria monocytogenes is a food-borne pathogen which causes listeriosis and is difficult to eradicate from seafood processing environments; therefore, more effective control methods need to be developed. This study investigated the effectiveness of three bacteriophages (LiMN4L, LiMN4p and LiMN17), individually or as a three-phage cocktail at ≈9 log10 PFU/ml, in the lysis of three seafood-borne L. monocytogenes strains (19CO9, 19DO3 and 19EO3) adhered to a fish broth layer on stainless steel coupon (FBSSC) and clean stainless steel coupon (SSC), in 7-day biofilm, and dislodged biofilm cells at 15 ± 1 °C. Single phage treatments (LiMN4L, LiMN4p or LiMN17) decreased bacterial cells adhered to FBSSC and SSC by ≈3–4.5 log units. Phage cocktail reduced the cells on both surfaces (≈3.8–4.5 and 4.6–5.4 log10 CFU/cm2, respectively), to less than detectable levels after ≈75 min (detection limit = 0.9 log10 CFU/cm2). The phage cocktail at ≈5.8, 6.5 and 7.5 log10 PFU/cm2 eliminated Listeria contamination (≈1.5–1.7 log10 CFU/cm2) on SSC in ≈15 min. One-hour phage treatments (LiMN4p, LiMN4L and cocktail) in three consecutive applications resulted in a decrease of 7-day L. monocytogenes biofilms (≈4 log10 CFU/cm2) by ≈2–3 log units. Single phage treatments reduced dislodged biofilm cells of each L. monocytogenes strain by ≈5 log10 CFU/ml in 1 h. The three phages were effective in controlling L. monocytogenes on stainless steel either clean or soiled with fish proteins which is likely to occur in seafood processing environments. Phages were more effective on biofilm cells dislodged from the surface compared with undisturbed biofilm cells. Therefore, for short-term phage treatments of biofilm it should be considered that some disruption of the biofilm cells from the surface prior to phage application will be required.
Combining Item Response Theory and Diagnostic Classification Models: A Psychometric Model for Scaling Ability and Diagnosing Misconceptions
Authors: Bradshaw Laine , Templin Jonathan
Published: August 2013

Traditional testing procedures typically utilize unidimensional item response theory (IRT) models to provide a single, continuous estimate of a student’s overall ability. Advances in psychometrics have focused on measuring multiple dimensions of ability to provide more detailed feedback for students, teachers, and other stakeholders. Diagnostic classification models (DCMs) provide multidimensional feedback by using categorical latent variables that represent distinct skills underlying a test that students may or may not have mastered. The Scaling Individuals and Classifying Misconceptions (SICM) model is presented as a combination of a unidimensional IRT model and a DCM where the categorical latent variables represent misconceptions instead of skills. In addition to an estimate of ability along a latent continuum, the SICM model provides multidimensional, diagnostic feedback in the form of statistical estimates of probabilities that students have certain misconceptions. Through an empirical data analysis, we show how this additional feedback can be used by stakeholders to tailor instruction for students’ needs. We also provide results from a simulation study that demonstrate that the SICM MCMC estimation algorithm yields reasonably accurate estimates under large-scale testing conditions.
Phosphodiesterase 5 inhibitor acts as a potent agent sensitizing acute myeloid leukemia cells to 67‐kDa laminin receptor‐dependent apoptosis
Authors: Kumazoe Motofumi , Kim Yoonhee , Bae Jaehoon , Takai Mika , Murata Motoki , Suemasu Yumi , Sugihara Kaori , Yamashita Shuya , Tsukamoto Shuntaro , Huang Yuhui , Nakahara Kanami , Yamada Koji , Tachibana Hirofumi
Published: August 2013

(−)‐Epigallocatechin‐3‐O‐gallate (EGCG), a polyphenol in green tea, induces apoptosis in acute myeloid leukemia (AML) cells without affecting normal cells. In this study, we observed that cGMP acts as a cell death mediator of the EGCG‐induced anti‐AML effect through acid sphingomyelinase activation. EGCG activated the Akt/eNOS axis, a well‐known mechanism in vascular cGMP upregulation. We also observed that a major cGMP negative regulator, phosphodiesterase 5, was overexpressed in AML cells, and PDE5 inhibitor, an anti‐erectile dysfunction drug, synergistically enhanced the anti‐AML effect of EGCG. This combination regimen killed AML cells via overexpressed 67‐kDa laminin receptors.
PERSPECTIVAS TEÓRICAS USADAS PARA EL ESTUDIO DE LA RESPONSABILIDAD SOCIAL EMPRESARIAL: UNA CLASIFICACIÓN CON BASE EN SU RACIONALIDAD
Authors: Alvarado Herrera Alejandro , Bigné Alcañiz Enrique , Currás Pérez Rafael
Published: August 2013

Based on an in-depth review of relevant literature published in the last 38 years, this work has two main objectives. First of all, it is aimed at identifying, reviewing, and synthesizing theories used in the literature for studying Corporate Social Responsibility (CSR). It discusses both the fundamental premises and the main criticism to which it has been subject. Secondly, it is geared toward classifying these theories by means of the application of the two following criteria: (i) the underlying primary rationality of each theory, and (ii) the conception of the role of business institutions in the society for which they advocate. This classification is a useful tool for properly combining theoretical perspectives and various rationalities, thus enriching the work of those who are concerned with the study of CSR.
Oceanic wave-balanced surface fronts and filaments
Authors: McWilliams James C. , Fox-Kemper Baylor
Published: August 2013

A geostrophic, hydrostatic, frontal or filamentary flow adjusts conservatively to accommodate a surface gravity wave field with wave-averaged, Stokes-drift vortex and Coriolis forces in an altered balanced state. In this altered state, the wave-balanced perturbations have an opposite cross-front symmetry to the original geostrophic state; e.g. the along-front flow perturbation is odd-symmetric about the frontal centre while the geostrophic flow is even-symmetric. The adjustment tends to make the flow scale closer to the deformation radius, and it induces a cross-front shape displacement in the opposite direction to the overturning effects of wave-aligned down-front and up-front winds. The ageostrophic, non-hydrostatic, adjusted flow may differ from the initial flow substantially, with velocity and buoyancy perturbations that extend over a larger and deeper region than the initial front and Stokes drift. The largest effect occurs for fronts that are wider than the mixed layer deformation radius and that fill about two-thirds of a well-mixed surface layer, with the Stokes drift spanning only the shallowest part of the mixed layer. For even deeper mixed layers, and especially for thinner or absent mixed layers, the wave-balanced adjustments are not as large.
Shape of optimal active flagella
Authors: Lauga Eric , Eloy Christophe
Published: August 2013

Many eukaryotic cells use the active waving motion of flexible flagella to self-propel in viscous fluids. However, the criterion governing the selection of particular flagellar waveforms among all possible shapes has proved elusive so far. To address this question, we derive computationally the optimal shape of an internally forced periodic planar flagellum deforming as a travelling wave. The optimum is here defined as the shape leading to a given swimming speed with minimum energetic cost. To calculate the energetic cost, we consider the irreversible internal power expended by the molecular motors forcing the flagellum, only a portion of which is dissipated in the fluid. This optimization approach allows us to derive a family of shapes depending on a single dimensionless number quantifying the relative importance of elastic to viscous effects: the Sperm number. The computed optimal shapes are found to agree with the waveforms observed on spermatozoon of marine organisms, thus suggesting that these eukaryotic flagella might have evolved to be mechanically optimal.
Onwards facing backwards: the rhetoric of science in nineteenth-century Greece
Authors: TAMPAKIS KOSTAS
Published: August 2013

The aim of this paper is to show how the Greek men of science negotiated a role for their enterprise within the Greek public sphere, from the institution of the modern Greek state in the early 1830s to the first decades of the twentieth century. By focusing on instances where they appeared in public in their official capacity as scientific experts, I describe the rhetorical schemata and the narrative strategies with which Greek science experts engaged the discourses prevalent in nineteenth- and early twentieth-century Greece. In the end, my goal is to show how they were neither zealots of modernization nor neutral actors struggling in isolated wastelands. Rather, they appear as energetic agents who used scientific expertise, national ideals and their privileged cultural positions to construct a rhetoric that would further all three. They engaged eagerly and consistently with emerging political views, scientific subjects and cultural and political events, without presenting themselves, or being seen, as doing anything qualitatively different from their peers abroad. Greek scientists cross-contextualized the scientific enterprise, situating it in the space in which they were active.
Jehovah's Witnesses as Un-Americans? Scriptural Injunctions, Civil Liberties, and Patriotism
Authors: KNOX ZOE
Published: August 2013

In the United States, the steadfast refusal of the Jehovah's Witnesses to perform some of the most basic rituals of citizenship has led champions of Americanism to cast them as unpatriotic and even seditious. The Watch Tower Society, the corporate body of the Witnesses, has responded to these accusations by presenting Witnesses as upstanding citizens, only ever departing from the letter of the law when there is a conflict between secular legal directive and scriptural injunction. This essay argues that the gulf between the popular perception of the Witnesses as poor citizens, particularly during the middle decades of the twentieth century, and the society's own representation of its members as assets to their communities highlights the contested and mutable nature of the label un-American. Furthermore, it argues that there is a paradox in the place of the Jehovah's Witnesses in modern American history: though operating beyond the pale of understood norms of citizenship, they have been fundamental to shaping the First Amendment freedoms enjoyed by all citizens. It seeks to contribute to two largely unwritten histories, namely the place of the Witnesses in American religious history, and the ever-changing yet resolutely politicized concept of the un-American.
Incentive salience: novel treatment strategies for major depression
Authors: Soskin David P. , Holt Daphne J. , Sacco Garret R. , Fava Maurizio
Published: August 2013

This article proposes that a recent shift in our understanding of dopamine function may support translational research to target deficits in positive emotions and reward processing in individuals with major depressive disorder (MDD). We review how dopamine functions to modulate approach behaviors in response to positive incentives, and we describe the incentive salience hypothesis, which posits that dopamine primarily modulates “wanting,” or anticipatory reward, rather than “liking,” or subjective pleasure. Although the incentive salience hypothesis was first proposed to help explain how drugs of abuse may reinforce harmful behaviors in the absence of continued pleasure or “liking,” it may also provide a basis for understanding and developing new treatment approaches for MDD. Specifically, it provides a rationale for combining behaviorally activating psychotherapies and pro-dopaminergic agents to target impaired reward processing in MDD.
Serotonergic modulation of glutamate neurotransmission as a strategy for treating depression and cognitive dysfunction
Authors: Pehrson Alan L. , Sanchez Connie
Published: August 2013

Monoamine-based treatments for depression have evolved greatly over the past several years, but shortcomings such as suboptimal efficacy, treatment lag, and residual cognitive dysfunction are still significant. Preclinical and clinical studies using compounds directly targeting glutamatergic neurotransmission present new opportunities for antidepressant treatment, with ketamine having a surprisingly rapid and sustained antidepressant effect that is presumably mediated through glutamate-dependent mechanisms. While direct modulation of glutamate transmission for antidepressant and cognition-enhancing actions may be hampered by nonspecific effects, indirect modulation through the serotonin (5-HT) system may be a viable alternative approach. Based on localization and function, 5-HT can modulate glutamate neurotransmission at least through the 5-HT1A, 5-HT1B, 5-HT3, and 5-HT7 receptors, which presents a rational pharmacological opportunity for modulating glutamatergic transmission without the direct use of glutamatergic compounds. Combining one or more of these glutamate-modulating 5-HT targets with 5-HT transporter inhibition may offer new therapeutic opportunities. The multimodal compounds vortioxetine and vilazodone are examples of this approach with diverse mechanisms, and their different clinical effects will provide valuable insights into serotonergic modulation of glutamate transmission for the potential treatment of depression and associated cognitive dysfunction.
Prevalence and Characterization of Mild Cognitive Impairment in Retired National Football League Players
Authors: Randolph Christopher , Karantzoulis Stella , Guskiewicz Kevin
Published: August 2013

It has been hypothesized that exposure to repetitive head trauma from contact sports over a long-playing career may eventuate in an increased risk of late-life cognitive impairment. There are currently two competing hypotheses about the possible mechanism underlying such impairment. One is the presence of a unique neurodegenerative disorder known as “chronic traumatic encephalopathy” (CTE). The other is diminished cerebral reserve leading to the earlier clinical expression of age-related neurodegenerative diseases such as mild cognitive impairment (MCI) and Alzheimer's disease (AD). The present study examined informant AD8 inventory data in a sample of 513 retired National Football League (NFL) players. These data were indicative of possible cognitive impairment in 35.1% of this relatively young sample. A comparison of neurocognitive profiles in a subsample of this group to a clinical sample of patients with a diagnosis of MCI due to AD revealed a highly similar profile of impairments. Overall, the data suggest that there may be an increased prevalence of late-life cognitive impairment in retired NFL players, which may reflect diminished cerebral reserve. The findings are considered preliminary, but emphasize the need for larger, controlled studies on this issue. (JINS, 2013,19, 1–8)
Unmittelbare Auswirkungen einzelner Bewegungseinheiten auf das Bedürfnis zu rauchen
Authors: Ledochowski Larissa , Taylor Adrian H. , Haasova Marcela , Faulkner Guy E. , Ussher Michael H. , Kopp Martin
Published: August 2013

Beurteilung der Datenlage zu den unmittelbaren Auswirkungen einer Bewegungseinheit in der Raucherentwöhnung bzw. bei temporärer Nikotinabstinenz, auf die Entzugssymptomatik, sowie auf das Verlangen nach Zigaretten. Es wurde eine systematische Bewertung von im Zeitraum Dezember 1975 – Dezember 2011 veröffentlichten Fachartikeln, die den Einfluss einer Bewegungseinheit im Vergleich zu einer Kontrollbedingung auf die Nikotinabstinenz untersuchten, durchgeführt. Neben einer Beschreibung der Studiendesigns werden die Ergebnisse zu den verwendeten Zielvariablen, die durchschnittliche Nikotinabstinenzdauer, Art und Ausmaß der Bewegungseinheit und verwendete Erhebungsinventare tabellarisch dargestellt. 23 von 24 Studien, die akute Auswirkungen von körperlicher Aktivität mit einer passiven Kontrollsituation bei Rauchern verglichen, berichten von positiven Einflüssen der Bewegungseinheit auf das Verlangen zu rauchen. Eine Reduktion des Verlangens nach Zigaretten wurde sowohl bei Bewegungseinheiten von hoher (60 – 80 % Herz Frequenz Reserve [HRR] über einen Zeitraum von ca. 30 min.) und moderater Intensität (24 % HRR über einen Zeitraum von ca. 15 Minuten) als auch bei geringer Intensität (isometrische Übungen für ca. 5 min.) festgestellt. 13 Studien zeigten eine signifikante Reduktion der Entzugssymptomatik während und nach Bewegung. In 5 Studien wurde ein 2- bis 3- mal längerer Zeitraum bis zum Rauchen der ersten Zigarette nach der Bewegungseinheit beobachtet. Zudem berichten 6 Studien von einer Verbesserung der Stimmungslage während und nach der Bewegungseinheit. Einzelne Bewegungseinheiten können in der Raucherentwöhnung zur Reduktion der Entzugssymptomatik und des Bedürfnisses zu rauchen beitragen. Bei nicht vorhandener Abstinenzmotivation kann durch einzelne Bewegungseinheiten eine Verringerung der Anzahl konsumierter Zigaretten erreicht werden.
Island of hope
Authors: Jacobs Howy
Published: August 2013

Two years on from the terrorist massacre in Norway, Howy argues that we still need to rebut the pernicious ideology that motivated the perpetrator.
Pigment Epithelium-Derived Factor Secreted from Retinal Pigment Epithelium Facilitates Apoptotic Cell Death of iPSC
Authors: Kanemura Hoshimi , Go Masahiro J. , Nishishita Naoki , Sakai Noriko , Kamao Hiroyuki , Sato Yoji , Takahashi Masayo , Kawamata Shin
Published: August 2013

We show that pigment epithelium-derived factor (PEDF), which is secreted from primary or iPSC-derived retinal pigment epithelium (RPE), dramatically inhibits the growth of iPSCs. PEDF is detected abundantly in culture supernatants of primary or iPSC-derived RPE. Apoptotic cell death is induced in iPSC when co-cultured with RPE, a process that is significantly blocked by addition of antibody against PEDF. Indeed, addition of recombinant PEDF to the iPSC cell culture induces apoptotic cell death in iPSCs, but the expression of pluripotency related-genes is maintained, suggesting that PEDF causes cell death, not differentiation, of iPSCs. To recapitulate this event in vivo, we examined tumor formation in NOG mice after subcutaneous injection of iPSCs with or without an iPSC-derived RPE sheet (2.5 × 105 RPE cells). We observed that the tumor forming potential of iPSCs was significantly suppressed by simultaneous transplantation with an iPSC-derived RPE sheet.
Experimental technique for quick and efficient lensed fibre to ridge waveguide coupling
Authors: Morrissey Padraic Edward , Goulding David , Sheehan Robert , Roycroft Brendan , Peters Frank H.
Published: August 2013

The authors describe a fast and efficient technique for lensed fibre to waveguide coupling, based upon imaging the waveguide facets. In this technique, the lensed fibre is scanned across a ridge waveguide facet while the reflected power from the facet is measured through a circulator. The measurements allow for the facet to be imaged and the lensed fibre location that provides optimum coupling can be determined. The technique provides an optimal method of coupling light into micron‐scale passive waveguide structures, with an efficiency close to that of the theoretical limit.
Analytical winding size optimisation for different conductor shapes using Ampère's Law
Authors: Wojda Rafal P. , Kazimierczuk Marian K.
Published: August 2013

In this study, an analytical optimisation of the foil, strip, square and solid‐round‐wire winding inductors conducting sinusoidal current is performed. The Ampère law is used to derive analytical equations for the AC‐to‐DC winding resistance ratio of different shape inductor windings valid at low and medium frequencies. These equations are used to perform optimisation of windings to obtain the global minimum of the winding AC resistance of the foil and strip wire windings and the local minimum of the winding AC resistance for the square and solid‐round‐wire windings. Derivations of AC‐to‐DC winding resistance ratio and winding AC resistance based on Ampère's law for the solid‐round‐wire windings are compared to Dowell's equation. Results of the predicted winding AC resistance based on Ampère's law for the solid‐round‐wire windings are validated by experimental results.
Space vector modulation strategy for VIENNA rectifier and load unbalanced ability
Authors: Hang Lijun , Zhang Ming , Li Bin , Huang Long , Liu Shirong
Published: August 2013

The space vector modulation strategy for the three‐phase/wire/level VIENNA rectifier is analysed in this study. Furthermore, the voltage balancing ability of DC‐link neutral point is demonstrated as well. The maximum unbalanced rate between the loads for dual‐output under different modulation indices m is theoretically calculated when the converter works in unity power factor. A robust controller to balance the output voltage under the unbalanced load for different modulation indices is proposed. An experimental prototype was built to verify the theoretical analysis. The voltages for dual‐output are balanced when the converter works as a power factor corrector, and therefore the theoretical analysis is verified. Finally, the series of tested maximum unbalanced rate between the loads for dual‐output under different modulation indices m was given, which verifies the theoretical analysis.
Analysis of dc‐link capacitor current in three‐level neutral point clamped and cascaded H‐bridge inverters
Authors: Orfanoudakis Georgios I. , Yuratich Michael A. , Sharkh Suleiman M.
Published: August 2013

Dc‐link capacitor sizing is a critical aspect of inverter design. This study investigates capacitor sizing for three‐level neutral‐point‐clamped and cascaded H‐bridge inverters, based on an analysis of dc‐link capacitor current. Methods used to derive expressions for the root‐mean‐square (rms) value and harmonic spectrum of the capacitor current in two‐level inverters, are extended to the three‐level inverters. A new numerical approach is also proposed for calculating the capacitor rms current and voltage ripple. MATLAB code is given for the proposed approach, which can be easily adapted to different modulation strategies and applied to higher‐level inverters. Capacitor sizing parameters derived according to this approach are presented for a number of common modulation strategies and are used to compare the requirements of the examined three‐level topologies. Results are validated by simulations using MATLAB‐Simulink.
New mixture of hybrid stacked multicell with half‐cascaded converter to increase voltage levels
Authors: Banaei Mohamad Reza , Kazemi Farhad Mohajel , Oskuee Mohammad Reza Jannati
Published: August 2013

This study presents a new topology of hybrid stacked multicell (SM) converter which generates high number of output voltage levels with fewer number of power electronic switches. The proposed topology is composed of three parts including traditional SM converter, half‐cascaded converter and H‐bridge converter. In other words, this converter is the mixture of H‐bridge converter and SM converter series with half‐cascaded converter. Number of output voltage levels and the root‐mean‐square value in proposed converter is four times than that of traditional flying capacitor multicell and SM converters. Moreover, it improves output voltage frequency spectrum and decreases the number and rating of components, stored energy and rating of flying capacitors which are available in the proposed converter. For switching this converter, phase‐shifted pulse‐width modulation method has been used. Therefore the self‐balancing trait of the flying capacitor converter is preserved in presented converter. The suggested topology is simulated using MATLAB/SIMULINK software, and simulation results are presented to indicate the well‐performance of the novel converter. In addition, the experimental results of proposed topology prototype have been presented to validate its practicability.
Asymmetrical multilevel converter topology with reduced number of components
Authors: Babaei Ebrahim , Farhadi Kangarlu Mohammad , Hosseinzadeh Mohammad Ali
Published: August 2013

In this study, firstly a new basic unit is proposed for multilevel converters. The proposed basic units are used as building blocks to form a cascaded multilevel converter. In other words, the proposed topology consists of cascaded basic units. The proposed basic unit and the proposed multilevel converter use lower number of switching devices and gate driver circuits. In the proposed topology, two design parameters are available: the number of cascaded basic units and the number of dc voltage sources in each basic unit. These two parameters can be used to design the desired multilevel converter based on the operational conditions. Therefore the proposed topology offers good flexibility in designing. An algorithm for determining the values of the dc voltage sources is given in order to generate maximum number of voltage levels. The comparison results with some recently introduced topologies show that the proposed topology effectively reduces the components count. The simulation results obtained in PSCAD/EMTDC as well as the experimental results of a 51‐level inverter based on the proposed topology are presented to verify its performance.
Research on cascaded three‐phase‐bridge multilevel converter based on CPS‐PWM
Authors: Lu Zhi‐G. , Zhao Li‐L. , Zhu Wan‐P. , Wu Chun‐J. , Qin Yu‐S.
Published: August 2013

Cascaded multilevel converters are emerging as a new breed of power converter options for high‐voltage and high‐power applications. A cascaded three‐phase‐bridge (C3PB) multilevel topology is proposed in this study. The new multilevel converter topology is derived from an optimum combination of three‐phase voltage source converter modules and it needs fewer switches and dc capacitors than Δ‐connected cascaded H‐bridge converter under the similar operation condition. The characteristics of the C3PB converter are presented through analysing its current relationship, voltage relationship and power allocation in detail; the analysis results show that all the converter modules equally share the output power. Based on carrier phase‐shifted pulse‐width modulation (CPS‐PWM) technique, simulation results of two‐level and three‐level inverter are given to verify the theoretical analysis; meanwhile, CPS‐PWM and power decoupling control method are employed to validate the three‐level C3PB rectifier. Finally, based on Digital Signal Processor (DSP) + Field Programmable Gate Array (FPGA) control board, a lab prototype is built to verify the validity and feasibility of the proposed C3PB converter along with the proposed control method.
Analysis and design of isolated flyback voltage‐multiplier converter for low‐voltage input and high‐voltage output applications
Authors: Zhiguo Zhang , Lin Zhou
Published: August 2013

An isolated flyback voltage‐multiplier (VM) converter is presented in this study in light of the basic line frequency voltage‐multiplying rectifier. The proposed circuit with a high conversion ratio operates in discontinuous conduction mode and combines the merits of the VM with flyback converters. It is very suitable to be used in low‐voltage input and high‐voltage output applications where compact size and a high conversion ratio are needed. The operations and prominent characteristics of the circuit are described, and the dynamic and steady‐state transfer function of the output‐voltage/input‐voltage is also derived. A laboratory prototype has been built based on the analysis. The validity of analysis for this circuit is verified by experimental results.
Space vector modulation strategy for neutral‐point voltage balancing in three‐level inverter systems
Authors: Choi Ui‐Min , Lee Kyo Beum
Published: August 2013

This study proposes a space vector modulation (SVM) strategy to balance the neutral‐point voltage of three‐level inverter systems. The proposed method is implemented by combining conventional symmetric SVM with nearest three‐vector (NTV) modulation. The conventional SVM is converted to NTV modulation by properly adding or subtracting a minimum gate‐on time. In addition, using this method, the switching frequency is reduced and a decrease of switching loss would be yielded. The neutral‐point voltage is balanced by the proposed SVM strategy without additional hardware or complex calculations. Simulation and experimental results are shown to verify the validity and feasibility of the proposed SVM strategy.
Natural frame‐based strategy for Vienna‐type rectifier with light unbalanced input voltages
Authors: Liu Sensen , Hang Lijun , Zhang Ming
Published: August 2013

When the Vienna‐type rectifier works at unbalanced input operation conditions, the dc‐link voltage ripples and the dc component of the reactive power will be introduced. Therefore a novel control scheme based on natural frame is proposed. The fundamental positive‐/negative‐sequence voltage components are derived by applying an early developed direct decoupled synchronisation method. A natural abc frame‐based current control loop, which considerably reduces total algorithm complexity and also helps to reduce the reactive components size and total loss in comparison with the traditional dual current control schemes, is proposed based on the mathematical modelling of Vienna rectifier under unbalanced input conditions. In addition, the static operation region of the Vienna‐type rectifiers is analysed and derived. Finally, the experimental results are given to verify the effectiveness of the proposed control scheme and the conclusion. Performance comparison between the traditional controller and proposed controller is demonstrated by the experimental results.
New five‐level inverter‐based grid‐connected power conversion interface
Authors: Wu Jinn‐Chang , He Mao‐Jhang , Jou Hurng‐Liahng
Published: August 2013

In this study, a five‐level inverter‐based grid‐connected power conversion interface is proposed. The output current of grid‐connected power conversion interface is controlled to be sinusoidal and in phase with the utility voltage so as to perform the unity power factor. The grid‐connected power conversion interface is configured by a DC–DC boost converter and a proposed five‐level inverter. The DC–DC boost converter is employed to boost a lower DC voltage source. The presented five‐level inverter is composed of a series/parallel capacitor set and a full‐bridge converter. The presented five‐level inverter contains only five power electronic switches, thus simplifying the circuit configuration. In addition, only one power electronic switch is switched in high frequency and only three semiconductor devices are conducting in series at the same time in the presented five‐level inverter. Thus, the power loss will be reduced and the power efficiency will be improved. Moreover, the control for balancing the voltages of DC capacitors of the presented five‐level inverter is simplified because the DC capacitors are discharged in series and in parallel alternately. A prototype is developed and tested to verify the performance of the proposed grid‐connected power conversion interface. The experimental results show that the proposed grid‐connected power conversion interface achieves the expected performance.
Fast space vector modulation algorithm for multilevel inverters and its extension for operation of the cascaded H‐bridge inverter with non‐constant DC sources
Authors: Roodsari Babak Nia , Nowicki Edwin P.
Published: August 2013

A major advancement in the research area of space vector modulation (SVM) in recent years is the introduction of the nearest three vector algorithm. Nonetheless, computational intensity is still a drawback of SVM methods in real time applications, especially in the case of multilevel inverter operation. A very fast and scalable SVM algorithm is introduced in this study, referred to as the fixed coordinate sub‐triangle SVM (FCST‐SVM) approach. The proposed method permits the determination of switch states and efficient calculation of switch on‐time durations for a given N‐level inverter topology. Calculations are performed based on a proposed sub‐triangle approach with fixed coordinates in the space vector diagram. Avoiding calculating the coordinates of the nearest three voltage vectors is a significant advantage of the proposed algorithm compared with previous SVM approaches applied to multilevel inverters. An example of the application of this method is presented for the multilevel cascaded H‐bridge inverter when non‐constant isolated DC sources are subjected to random voltage deviations. MATLAB simulation results verify the feasibility of the proposed approach. Experimental results, using a TMS320F2812 digital signal processor, are also presented to verify the effectiveness of the proposed approach in decreasing the computational overhead in comparison with the conventional SVM method. For example, it is found that computational requirements for SVM decrease by a factor of 9.5 compared with the conventional method in the case of a three‐phase nine‐level cascaded H‐bridge inverter.
Robust predictive dual‐loop control strategy with reactive power compensation for single‐phase grid‐connected distributed generation system
Authors: Chen Yandong , Luo An , Shuai Zhikang , Xie Sanjun
Published: August 2013

A robust predictive dual‐loop control strategy with reactive power compensation is proposed for single‐phase grid‐connected distributed generation (DG) system located at the end of the feeder. The proposed control strategy mainly includes improved reactive current detection and robust predictive dual‐loop control. To reduce the long time delay in the conventional reactive current detection, the improved reactive current detection method based on the derivative and ip − iq algorithm is presented. In the inner current loop, a robust predictive deadbeat control (RPDC) is proposed to reduce the control delay in digital signal processor, and also enhances system robustness due to the filter inductance mismatch. In the outer loop, proportional–integral controller is applied to stabilise the dc‐link voltage, and power feedforward is used to speed up the system response. In z‐domain, the stability of RPDC is discussed, and the proper parameters are selected. Simulation and experimental results verified the validity of the proposed strategy.
Analysis and experimental study of an output feedback controller for a high‐order boost dc–dc converter
Authors: Chan Chok You
Published: August 2013

The analysis and experimental investigation of an analogue output feedback controller for high‐order boost dc–dc converter is presented. The controller incorporates both damping and integral action for enhanced performance. A comparative study of the conventional PI controller and the proposed controller shows that the latter's suitability for the high‐order converter has a sound theoretical basis. Some experimental results are provided to illustrate the features of the controller in the presence of reference voltage and load changes.
Single snapshot imaging method in multiple‐input multiple‐output radar with sparse antenna array
Authors: Gu Fufei , Chi Long , Zhang Qun , Zhu Feng
Published: August 2013

In this study, a single snapshot imaging method of the moving targets in multiple‐input multiple‐output (MIMO) radar with sparse antenna array is proposed. First, a configuration of sparse antenna array is presented and then, on the basis of this, an imaging method based on compressed sensing theory is put forward. With this method, the image of a moving target can be achieved via single snapshot imaging processing. It not only can avoid motion compensation processing as required by conventional inverse synthetic aperture radar imaging, but also can dramatically reduce the number of the antenna elements, which is a quite large number in the typical configuration of MIMO radar system with linear antenna array. Finally, the effectiveness of this method is validated by the simulation results.
L∞ fuzzy filter for non‐linear systems with intermittent measurement and persistent bounded disturbances
Authors: Noh Sun Young , Park Jin Bae , Joo Young Hoon
Published: August 2013

This study is concerned with an L∞ filtering problem for non‐linear systems with persistent bounded disturbances and intermittent measurements. The non‐linear plant is represented by the Takagi–Sugeno (T–S) fuzzy model that is employed to approximate the non‐linear dynamic systems. The system measurements may be unavailable at any sample time and the probability of the occurrence of missing data is assumed to be known. In this study, to design the L∞ fuzzy filter with the estimation error, the estimation error because of persistent bounded disturbance is minimised by some linear matrix inequalities and the filter error system is stochastically stable in the mean square. A stochastic variable satisfying the Bernoulli random binary distribution is utilised to model the phenomenon of the missing data. Finally, the results indicate that the proposed method attenuates the peak of estimation error and preserves a guaranteed L∞‐gain performance.