bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative analysis of curro pore growth on n‐type InP
Authors: Leisner Malte , Carstensen Jürgen , Föll Helmut 
Published: November 2010

AbstractIn this work the growth of currentline‐oriented pores (curro pores) in (100) n‐type InP has been investigated on substrates of different doping concentration ND. Additionally, Fast‐Fourier‐Transform Impedance Spectroscopy (FFT IS) has been performed in‐situ during the etching. In the framework of the developed model of curro pore growth it was possible to extract quantitative data, which were hitherto not retrievable in‐situ. These data include the potential drop in the space‐charge‐region at the pore tips USCR and the corresponding space‐charge‐region capacitance CSCR, which are now directly accessible by FFT IS. Moreover, the width of the space‐charge‐region dSCR could be calculated, which defines the pore wall thickness, i.e. the doping concentration dependent spacing of the curro pores in the hexagonal lattice in which the curro pores grow for all doping concentrations.The critical field strength of the avalanche breakdown – the mechanism of hole‐generation during curro pore growth – could also be calculated from the experimental data. It could be shown that the growth mode of curro pores is based on a constant potential drop at the pore tips, which together with a constant pore tip geometry keeps the maximum field strength Em of the avalanche breakdown process at the pore tips constant. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of currentline pore growth in n‐type InP and in n‐type Si
Authors: Cojocaru Ala , Leisner Malte , Carstensen Jürgen , Föll Helmut 
Published: November 2010

AbstractIn this work the growth of currentline‐oriented pores in (100) n‐type InP and in (100) n‐type Si for different doping concentrations has been studied. The pore morphology of both pore types is very similar, as is the characteristic behavior of the etching current. These similarities strongly indicate, that the underlying growth mechanisms of these pores in InP and Si are the same. A model for the currentline pores in both semiconductors is introduced, focusing on the strong diffusion limitation of species (reactants or products) at the pore tips. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photonic porous silicon‐based hybrid particles by soft‐lithography
Authors: Cheng Hua , Zhou Xuechang , Tsang Chun Kwan , Cheng Jian‐Wen , Liang Fengxia , Zheng Bo , Li Yang Yang 
Published: November 2010

AbstractHere we present a simple and effective method to fabricate porous silicon photonic crystal‐based hybrid particles by soft lithography. These fabricated hybrid particles are composed of pristine porous silicon structures strengthened by a polymer infused nanocomposite framework. The pristine porous silicon moiety serves as a sensor because of its environmentally sensitive optical features, while the polymer‐infused moiety provides a mechanically resilient scaffold and its invariant optical features can be used as an optical barcode and a built‐in self‐reference for optical sensing. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impregnation of porous silicon with conducting polymers
Authors: Harraz Farid A. 
Published: November 2010

AbstractFabrication of porous silicon layers using the electrochemical technique followed by filling the nanopores with a group of conducting polymers is investigated. Our findings revealed that the deposition of polymer proceeds homogeneously inside the nanopores strating from the pore bottom and propagates into the outer surface. The polymerization process was conducted and controlled by the potentiostatic and galvanostatic modes with charactarestic, defined polymerization stages.As‐formed hybrid nanocomposites were charactarized using different analytical techniques. Polypyrrole, polyaniline and polythiophene were tested in this study. By selective dissolution of porous silicon template, polymeric nanowires were obtained. The fabrication process, the electrochemical measurements and the porous silicon filling mechanism with polymer are throughly addressed and discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carrier mobilities in multicrystalline silicon wafers made from UMG‐Si
Authors: Lim Bianca , Wolf Martin , Schmidt Jan 
Published: November 2010

AbstractWe investigate majority‐ and minority‐carrier mobilities in multicrystalline silicon (mc‐Si) made from upgraded metallurgical‐grade (UMG) feedstock. Since UMG‐Si contains high amounts of both boron and phosphorus, a decrease of the carrier mobility due to increased scattering at ionized impurities is expected. Minority‐carrier mobilities are determined by measuring effective carrier lifetimes τeff on as‐cut wafers, where τeff is limited by carrier diffusion to the unpassivated surfaces. By examining a wafer cut vertically from the mc‐Si ingot, we indeed find a reduction in minority‐carrier mobility μmin with increasing dopant density. In addition, we find a further strong reduction of μmin in the transition region from p ‐ to n ‐type silicon. Similar results are obtained regarding the majority‐carrier mobility μmaj, which is investigated by combining measurements of the resistivity ρ and the equilibrium hole concentration p0 (equilibrium electron concentration n0 in n ‐type material) obtained from electrochemical capacitance‐voltage measurements. Apart from an overall reduction in μmaj compared to values measured in non‐compensated p ‐type mc‐Si, an additional pronounced decrease of the mobility with increasing compensation level is observed. This additional reduction can be explained by reduced screening of the ionized scattering centers. We propose a parameterization of the experimental data based on the Brooks‐Herring equation and find excellent agreement between the two (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction of absorption loss in multicrystalline silicon via combination of mechanical grooving and porous silicon
Authors: Ben Rabha Mohamed , Mohamed Seifeddine Belhadj , Dimassi Wissem , Gaidi Mounir , Ezzaouia Hatem , Bessais Brahim 
Published: November 2010

AbstractSurface texturing of silicon wafer is a key step to enhance light absorption and to improve the solar cell performances. While alkaline‐texturing of single crystalline silicon wafers was well established, no efficient chemical solution has been successfully developed for multicrystalline silicon wafers. Thus, the use of alternative new methods for effective texturization of multicrystalline silicon is worth to be investigated. One of the promising texturing techniques of multicrystalline silicon wafers is the use of mechanical grooves. However, most often, physical damages occur during mechanical grooves of the wafer surface, which in turn require an additional step of wet processing‐removal damage. Electrochemical surface treatment seems to be an adequate solution for removing mechanical damage throughout porous silicon formation. The topography of untreated and porous silicon‐treated mechanically textured surface was investigated using scanning electron microscopy (SEM). As a result of the electrochemical surface treatment, the total reflectivity drops to about 5% in the 400‐1000 nm wavelength range and the effective minority carrier diffusion length enhances from 190 µm to about 230 µm (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A natural source of porous biosilica for nanotech applications: the diatoms microalgae
Authors: De Stefano Luca , De Stefano Mario , De Tommasi Edoardo , Rea Ilaria , Rendina Ivo 
Published: November 2010

AbstractSeveral biological organisms, from some sea shells to butterflies, exhibit beautiful and sophisticated organs, developed during the evolution of each species, which properties are defined by their nanostructures. The marine diatoms are microscopic algae enclosed between two valves of hydrated amorphous silica. These intricate structures, called frustules, show quite symmetric patterns of micrometric and nanometric pores. Their strong similarity with man‐made materials, such as synthetic zeolites, or porous silicon and alumina, suggests to exploit the physical properties of the frustules in nanotech applications. In this paper, we review the most relevant results achieved in our laboratory, and all over the world, about the discovery of surprising features that can be found in the characterization of these natural porous biosilica materials. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mesoporous silicon particles as intravascular drug delivery vectors: fabrication, in‐vitro, and in‐vivo assessments
Authors: Chiappini Ciro , Tasciotti Ennio , Serda Rita E. , Brousseau Lou , Liu Xuewu , Ferrari M. 
Published: November 2010

AbstractPorous silicon is an attractive biomaterial for drug delivery thanks to its biocompatibility, biodegradability, ease of fabrication, tunable nanostructure, and porous network. Herein we briefly present the development of a multi‐stage delivery vector that leverages these advantages to enhance delivery of systemically administered therapeutic agents. We illustrate the rational design, objective‐oriented fabrication and geometric control of first stage porous silicon microparticles. We describe how geometry affects the biodistribution of first stage vectors and how their porous structure affects the loading and release of second stage theranostic payloads. We describe the mechanism of cellular internalization and intracellular trafficking of particles. Finally we present two multi‐stage vector prototypes for the delivery of magnetic resonance imaging contrast agents and small interfering RNA (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impedance spectra under forward and reverse bias conditions in gold/porous silicon/p‐Si structures
Authors: Fonthal Faruk , Chavarria Mario A. 
Published: November 2010

AbstractAbstract – The AC electrical characterization of Au/porous silicon/p‐Si structure is presented. The low porosity porous silicon layers were prepared by electrochemical etching in p‐type silicon 〈100〉 with two resistivities. The AC electrical measurements capacitance–conductance–frequency were performed from 5 Hz to 10 MHz, at room temperature in the DC range of ±2 V. We studied two structures; first a conductor type Au/PS/Au and second diode type Au/PS/p‐Si/Al. We found the relationship between the bias voltage in the PS/p‐Si heterostructures with the depletion region formation and the conduction mechanism presents in these structures. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chrysophanic acid blocks proliferation of colon cancer cells by inhibiting EGFR/mTOR pathway
Authors: Lee Myung Sun , Cha Eun Young , Sul Ji Young , Song In Sang , Kim Ji Yeon 
Published: November 2010

AbstractInactivation of epidermal growth factor receptor (EGFR) is a prime method used in colon cancer therapy. Here it is shown that chrysophanic acid, a natural anthraquinone, has anticancer activity in EGFR‐overexpressing SNU‐C5 human colon cancer cells. Chrysophanic acid preferentially blocked proliferation in SNU‐C5 cells but not in other cell lines (HT7, HT29, KM12C, SW480, HCT116 and SNU‐C4) with low levels of EGFR expression. Chrysophanic acid treatment in SNU‐C5 cells inhibited EGF‐induced phosphorylation of EGFR and suppressed activation of downstream signaling molecules, such as AKT, extracellular signal‐regulated kinase (ERK) and the mammalian target of rapamycin (mTOR)/ribosomal protein S6 kinase (p70S6K). Chrysophanic acid (80 and 120 µm) significantly blocked cell proliferation when combined with the mTOR inhibitor, rapamycin. These findings offer the first evidence of anticancer activity for chrysophanic acid via EGFR/mTOR mediated signaling transduction pathway. Copyright © 2010 John Wiley & Sons, Ltd.
Routine TOF‐SIMS instrument control using polycarbonate material
Authors: Fartmann Michael , Kersting Reinhard , Hagenhoff Birgit 
Published: November 2010

AbstractWe suggest the use of polycarbonate as reference material for the routine time of flight (TOF) SIMS (TOF‐SIMS) instrument control under quality management regulations (e.g. ISO/IEC 17025:2005). By monitoring an easy‐to‐determine relative peak area ratio, the performance of TOF‐SIMS instruments can well be assessed, in particular, with respect to the characterization of insulating samples. Copyright © 2010 John Wiley & Sons, Ltd.
Aldehyde Dehydrogenase Activity of Breast Cancer Stem Cells Is Primarily Due To Isoform ALDH1A3 and Its Expression Is Predictive of Metastasis
Authors: Marcato Paola , Dean Cheryl A. , Pan Da , Araslanova Rakhna , Gillis Megan , Joshi Madalsa , Helyer Lucy , Pan Luzhe , Leidal Andrew , Gujar Shashi , Giacomantonio Carman A. , Lee Patrick W. K. 
Published: November 2010

AbstractCancer stem cells (CSCs) are proposed to initiate cancer and propagate metastasis. Breast CSCs identified by aldehyde dehydrogenase (ALDH) activity are highly tumorigenic in xenograft models. However, in patient breast tumor immunohistological studies, where CSCs are identified by expression of ALDH isoform ALDH1A1, CSC prevalence is not correlative with metastasis, raising some doubt as to the role of CSCs in cancer. We characterized the expression of all 19 ALDH isoforms in patient breast tumor CSCs and breast cancer cell lines by total genome microarray expression analysis, immunofluorescence protein expression studies, and quantitative polymerase chain reaction. These studies revealed that ALDH activity of patient breast tumor CSCs and cell lines correlates best with expression of another isoform, ALDH1A3, not ALDH1A1. We performed shRNA knockdown experiments of the various ALDH isoforms and found that only ALDH1A3 knockdown uniformly reduced ALDH activity of breast cancer cells. Immunohistological studies with fixed patient breast tumor samples revealed that ALDH1A3 expression in patient breast tumors correlates significantly with tumor grade, metastasis, and cancer stage. Our results, therefore, identify ALDH1A3 as a novel CSC marker with potential clinical prognostic applicability, and demonstrate a clear correlation between CSC prevalence and the development of metastatic breast cancer.
PKCδ-Induced PU.1 Phosphorylation Promotes Hematopoietic Stem Cell Differentiation to Dendritic Cells
Authors: Hamdorf Matthias , Berger André , Schüle Silke , Reinhardt Jens , Flory Egbert 
Published: November 2010

AbstractHuman CD34+ hematopoietic stem cells (HSCs) exhibit the potential to differentiate into a variety of specialized blood cells. The distinct intracellular mechanisms that control cell fate and lineage commitment of these multipotent cells are not well defined. In this study, we investigate and modulate the signaling processes during HSC differentiation toward myeloid dendritic cells (mDCs). DC differentiation induced by the cytokines Granulocyte macrophage colony-stimulating factor (GM-CSF) and Interleukin-4 (IL-4) led to activation of the Extracellular-signal-regulated kinase (ERK), protein kinase C (PKC), and Janus kinase (JAK)/Signal Transducer and Activator of Transcription (STAT) but not the SAPK/c-Jun NH2-terminal kinase and p38 mitogen-activated protein kinase signaling pathways. From the activated signaling pathways the PKC isoform δ was found to phosphorylate the transcription factor PU.1, which is described as one of the key factors for myeloid HSC differentiation. On molecular level, PKCδ regulated PU.1 activity by affecting its transactivation activity, whereas its DNA binding activity remained unaffected. This was accompanied by PKCδ-induced phosphorylation of the PU.1 transactivation domain. Furthermore, treatment with PKC- and ERK1/2-specific signaling inhibitors impaired both HSC differentiation toward mDCs as well as phosphorylation-mediated transactivation activity of PU.1. Taken together, these results provide new insights into the molecular mechanisms promoting the differentiation process of HSCs toward mDCs and introduce the PKC isoform δ as critical mediator.
The Apical Polarity Determinant Crumbs 2 Is a Novel Regulator of ESC-Derived Neural Progenitors
Authors: Boroviak Thorsten , Rashbass Penny 
Published: November 2010

Abstract
ESCs undergoing neural differentiation in vitro display an intrinsic heterogeneity with a large subset of the cells forming polarized neural rosettes that maintain the neural progenitor microenvironment. This heterogeneity is not only necessary for normal development but also causes substantial technical challenges for practical applications. Here, we report a novel regulator of early neural progenitors, the apical polarity protein Crb2 (Crumbs homologue 2). Employing monolayer differentiation of mouse ESCs to model neurogenesis in vitro, we find that Crb2 is upregulated with Sox1 and Musashi at the onset of neuroepithelial specification and localizes to the apical side of neural rosettes. Stable Crb2-knockdown (KD) lines die at the onset of neural specification and fail to stabilize several apical polarity proteins. However, these cells are able to proliferate under self-renewing conditions and can be differentiated into mesodermal and endodermal lineages. Conversely, Crb2 overexpression during neural differentiation results in elevated levels of other apical polarity proteins and increases proliferation. Additionally, sustained overexpression of Crb2 reduces terminal differentiation into TuJ1-positive neurons. Furthermore, we demonstrate that Crb2 overexpression under self-renewing conditions increases glycogen synthase kinase (GSK)-3β inhibition, correlating with an increase in clonogenicity. To confirm the importance of GSK-3β inhibition downstream of Crb2, we show that Crb2-KD cells can be forced into neural lineages by blocking GSK-3β function and supplementing Epidermal Growth Factor (EGF) and basic Fibroblast Growth Factor (bFGF). Thus, this is the first demonstration that a member of the Crumbs family is essential for survival and differentiation of ESC-derived neural progenitors.
Dynamic optimal route search algorithm for car navigation systems with preferences by dynamic programming
Authors: Mainali Manoj Kanta , Mabu Shingo , Yu Shanqing , Eto Shinji , Hirasawa Kotaro 
Published: November 2010

AbstractOptimal route search to the destination is one of the most important functions of car navigation devices. The development of road traffic infrastructure has made it possible to receive real‐time information of the traffic situation. Route search algorithms for car navigation devices make use of this information to avoid the traffic congestions. Such algorithms should find the new optimal route efficiently when the traffic situation changes. Usually, the minimum traveling time or distance is considered to define the optimal route. However, the minimum traveling time or distance is not always what the user is looking for. The user may prefer to travel on a certain route even at the cost of traveling time or distance. Car navigation devices should consider such preferences when finding the optimal route. In this paper, we propose a dynamic programming algorithm to find the optimal route considering that it should deal with the changes of the traffic situation and multiple criteria. The proposed method uses the information from the previous computation to find the new optimal route considering user preferences when the traveling time of the road section changes. The proposed method was applied to a real road network to find the optimal route. Results show that the proposed method can find the user‐preferred optimal route. Simulation results also show better calculation time of the proposed method compared to the Dijkstra algorithm. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A minute asymmetrical current injection based anti‐islanding method for three‐phase grid‐connected photovoltaic inverters
Authors: Sun Xiang‐Dong , Matsui Mikihiko , Yu Byung‐Gyu , Koh Kang‐Hoon 
Published: November 2010

AbstractAn active anti‐islanding protection method based on the current control for a three‐phase grid‐connected photovoltaic inverter is proposed in this paper. The current of phase‐a is synchronous with the corresponding phase voltage at the point of common coupling in its positive half cycle, and a zero‐current zone is inserted at the end of the cycle in a negative half cycle. As for phase‐c, the zero‐current zone is inserted in the positive half cycle of the current, and the current in a negative half cycle of phase‐c is in phase with the corresponding phase voltage. Therefore, the currents of phase‐a and phase‐c in one cycle become slightly asymmetrical. Before the islanding takes place, the positive and negative half cycles of three‐phase voltages are symmetrical due to the operation of the grid voltage. While islanding takes place, a time difference between the positive and negative half cycles of the voltages of phase‐a and phase‐c will be generated and the islanding is detected in accordance with the successive cycles fulfilling the conditions of islanding identification. In order to measure zero‐crossings of the voltages accurately, an finite impulse response filter is used to smooth out the voltage harmonics and noises. Simulations and experiments for three‐phase three‐wire power systems have been carried out. The results verify that the proposed method can detect the islanding for a parallelRLCload or induction motors when the voltage frequency is within the range of the non‐detection zone. It is seen from the analysis of the detecting principle that there is no influence of temporal voltage frequency fluctuation on the proposed method even if a large load connected to a weak power system frequently starts up or stops. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Numerical study of the oscillation characteristics of a surface wave oscillator
Authors: Watanabe Osamu 
Published: November 2010

AbstractThe oscillation characteristics of a surface wave oscillator is analyzed numerically. The oscillation frequency due to Cherenkov instability can be controlled by the electron beam energy though the alteration of the accompanying temporal growth rate. The growth rate increases exponentially with the proximity of the beam to a corrugated metal plate. The oscillation frequency is not changed by this proximity. The peak of the growth rate of the Cherenkov instability is one or more orders higher than that of a Smith–Purcell type instability. Moreover, in frequency and wavenumbers, the difference of two instabilities is enlarged by the increase in the growth rate. Therefore, the influence of the Smith–Purcell type instability on the Cherenkov instability is decreased. IEEJ Trans 2010 DOI: 10.1002/tee.20611
Reduced order model predictive control with disturbance attenuation
Authors: Takahashi Masaaki , Hara Naoyuki , Kokame Hideki , Konishi Keiji 
Published: November 2010

AbstractThis paper deals with model predictive control (MPC) with disturbance attenuation. By introducing a decomposition method for a quadratic objective function, an MPC law is obtained from a reduced order optimization problem. The effectiveness of the proposed MPC law is demonstrated by numerical simulation.IEEJ Trans2010 DOI: 10.1002/tee.20613