bluuebunny/crossref_metadata_2025 huggingface dataset:
CYCLIC UNIVERSE WITH QUINTOM MATTER IN LOOP QUANTUM COSMOLOGY
Authors: XIONG HUA-HUI , QIU TAOTAO , CAI YI-FU , ZHANG XINMIN
Published: June 2009

In this paper, we study the possibility of model building of cyclic universe with Quintom matter in the framework of Loop Quantum Cosmology. After a general demonstration, we provide two examples, one with double-fluid and another double-scalar field, to show how such a scenario is obtained. Analytical and numerical calculations are both presented in the paper.
FORMATION OF CRYSTAL G PHASE IN HYDROGEN BONDED MESOGEN CONSTRUCTED BY p-n-ALKYL BENZOIC ACIDS WITH ORTHO-TOLUAMIDE
Authors: KUMAR CH. RAVI SHANKAR , SASTRY S. SREEHARI , MOHAN T. MADHU
Published: June 2009

New supramolecular hydrogen bonded mesogens are designed with the non-covalent interactions between the two polar groups. Interesting observations made in the synthesis of new hydrogen bonded mesogen between the mesogenic group p-n-alkyl benzoic acid with n representing the alkyl carbon number from pentyl to decyl of benzoic acid group and non-mesogen ortho-toluamide containing nitro group. The thermodynamic properties of the observed textures are studied by polarizing optical microscope and compared with the corresponding differential scanning calorimetry. The results of hydrogen-bonded mesogen are studied in comparison with the free p-n-alkyl benzoic acids. The intermolecular hydrogen bonding between the two polar groups convinced by FT-IR favours the formation of hydrogen-bonded mesogen with crystal G phase different from their constituents.
WHY HOLES ARE NOT LIKE ELECTRONS III: HOW HOLES IN THE NORMAL STATE TURN INTO ELECTRONS IN THE SUPERCONDUCTING STATE
Authors: HIRSCH J. E.
Published: June 2009

In recent work, we discussed the difference between electrons and holes in energy band in solids from a many-particle point of view, originating in the electron–electron interaction,1and from a single particle point of view, originating in the electron–ion interaction.2We proposed that superconductivity in solids only occurs when the Fermi level is close to the top of a band (hole carriers), that it originates in "undressing" of carriers from both the electron–electron and the electron–ion interaction, and that as a consequence holes in the normal state behave like electrons in the superconducting state.3However, the connection between both undressing effects was left unclear, as was left unclear how the transformation from hole behavior to electron behavior occurs. Here, we clarify these questions by showing that the same electron–electron interaction physics that promotes pairing of hole carriers and undressing of carriers from the electron–electron interaction leads to undressing of carriers from the electron–ion interaction and transforms the behavior of carriers from hole-like to electron-like. A complete reorganization of the occupation of single-particle energy levels occurs. Furthermore this phenomenon is connected with the expulsion of negative charge that we predict to occur in superconductors. These unexpected connections support the validity of our theoretical framework, the theory of hole superconductivity, to explain superconductivity in solids.
GAUGE FIELDS, QUANTIZED FLUXES AND MONOPOLE CONFINEMENT OF THE HONEYCOMB LATTICE
Authors: KOHMOTO MAHITO
Published: June 2009

Electron hopping models on the honeycomb lattice are studied. The lattice consists of two triangular sublattices, and it is non-Bravais. The dual space has non-trivial topology. The gauge fields of Bloch electrons have the U(1) symmetry and thus represent superconducting states in the dual space. Two quantized Abrikosov fluxes exist at the Dirac points and have fluxes 2π and -2π, respectively. We define the non-Abelian SO(3) gauge theory in the extended 3d dual space and it is shown that a monopole and anti-monoplole solution is stable. The SO(3) gauge group is broken down to U(1) at the 2d boundary. The Abrikosov fluxes are related to quantized Hall conductance by the topological expression. Based on this, monopole confinement and deconfinement are discussed in relation to time reversal symmetry and QHE. The Jahn–Teller effect is briefly discussed.
CRITICAL TEMPERATURE OF TRAPPED INTERACTING BOSE GASES
Authors: ZHANG CUILING , TAN LEI , ZHU KUNYAN
Published: June 2009

A new model is proposed to study the effect of mutual interaction revealed in a recent experiment.1 Unlike conventional Hartree–Fock theory, which only studies onset interactions between indistinguishable interacting bosons, our model further includes the mutual interaction between the condensate component and the thermal component. The derived condensate fraction and transition temperature explain the experimental data in a reliable manner.
DYNAMIC CRACK PROPAGATION IN FIVE-FOLD SYMMETRY QUASICRYSTALS
Authors: YIN ZHI-HUA , FAN TIAN-YOU , ZHU AI-YU
Published: June 2009

Based on the elasto-/hydro-dynamic model the dynamic properties of the five-fold symmetry quasicrystals with point groups 5, [Formula: see text] are investigated, by using the finite difference method. The problems including dynamic initiation of crack growth and fast crack propagation of this material are studied. The results show that the phonon–phason coupling effect plays an important role to the dynamic properties of the quasicrystals.
CRYSTAL GROWTH, THERMAL, OPTICAL, AND DIELECTRIC PROPERTIES OF L-LYSINE DOPED KDP CRYSTALS
Authors: PARIKH KETAN D. , DAVE DIPAK J. , JOSHI MIHIR J.
Published: June 2009

Single crystals of pure and various amount of L-lysine doped KDP crystals were grown from aqueous solution. The doping of L-lysine was confirmed by CHN analysis and FT-IR spectroscopy. Powder XRD was carried out to assess the single phase nature of the samples. The effect of doping on thermal stability of the crystals was carried out by TGA and the kinetic and thermodynamic parameters of dehydration were evaluated. It was found that as the amount of doping of amino acid, L-lysine, increased the thermal stability of the grown crystals decreased. However, the second-harmonic generation (SHG) efficiency of Nd :YAG laser and UV-vis spectroscopy studies indicated that as the L-lysine doping increased in KDP crystals the SHG efficiency and optical transmission percentage increased. The dielectric constant and the dielectric loss of L-lysine doped KDP crystals are lower than the pure KDP crystals. Hence L-lysine doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals. The results are discussed.
CMOS CIRCUIT DESIGN OF A TAKAGI-SUGENO FUZZY LOGIC CONTROLLER
Authors: SHAN WEIWEI , LIANG YAN , JIN DONGMING
Published: June 2009

This paper presents a low power CMOS analog integrated circuit of a Takagi–Sugeno fuzzy logic controller with voltage/voltage interface, small chip area, relatively high accuracy and medium speed, which is composed of several improved functional blocks. Z-shaped, Gaussian and S-shaped membership function circuits with compact structures are designed, performing well with low power, high speed and small areas. A current minimization circuit is provided with high accuracy and high speed. A follower-aggregation defuzzification block composed of several multipliers for center of gravity (COG) defuzzification is presented without using a division circuit. Based on these blocks, a two-input one-output singleton fuzzy controller with nine rules is designed under a CMOS 0.6 μm standard technology provided by CSMC. HSPICE simulation results show that this controller reaches an accuracy of ±3% with power consumption of only 3.5 mW (at ±2.5 V). The speed of this controller goes up to 0.625M Fuzzy Logic Inference per Second (FLIPS), which is fast enough for real-time control.
ACTIVE CIRCULATOR CIRCUITS USING OA, CCII, CFOA AND DVCC
Authors: SOLIMAN AHMED M.
Published: June 2009

A review of the two types of circulators using Operational Amplifiers (OA) with detailed comparison is given. Novel active circulator circuits using Current Conveyors (CCII) and Current Feedback Operational Amplifiers (CFOA) and Differential Voltage Current Conveyor (DVCC) are introduced. The proposed CCII circulator circuit uses six CCIIs and three floating resistors. Two different circulator types using the CFOA are given. A circulator circuit which uses three DVCCs and has the advantage of using three grounded resistors is also introduced.

Spice simulation results using 0.5 μm CMOS transistors are included to support the theoretical analysis and demonstrate comparisons among the different types of circulators.
BOOSTING THE PERFORMANCE OF SOFTWARE-BASED TRANSIENT ERRORS TOLERANT TECHNIQUES THROUGH COMPILER OPTIMIZATIONS
Authors: ZHANG WEI
Published: June 2009

This paper concentrates on studying to improve the performance of the state-of-the-art software-based fault tolerant technique — EDDI (Error Detection by Duplicated Instructions). We evaluate and analyze the performance of EDDI, and discover that some effective compiler optimizations targeting single-threaded programs with limited ILP become less effective for duplicated software. This paper then proposes the compiler-directed register de-replication to reduce the register pressure of EDDI. In addition, we evaluate the aggressive use of the delayed branch to exploit the control-independent instructions across both the original and the duplicated threads to further enhance the performance of EDDI. Our experimental results indicate that the performance overhead of EDDI can be reduced by up to 21.5%, with an average of 8.9%, by pure software optimizations.
MOS-C KHN FILTER USING VOLTAGE OP AMP, CFOA, OTRA AND DCVC
Authors: SOLIMAN AHMED M. , MADIAN AHMED H.
Published: June 2009

MOS-C realizations of the Kerwin–Huelsman–Newcomb (KHN) circuit using the commercially available Voltage Operational Amplifier (VOA) and the Current Feedback Operational Amplifier (CFOA) are reviewed in this paper. Additional MOS-C KHN realizations using the Operational Transresistance Amplifier (OTRA) and the Differential Current Voltage Conveyor (DCVC) are also included. MOS-C realizations of the KHN circuit using CMOS operational amplifier, CMOS current feedback operational amplifier and CMOS operational transresistance amplifier are also given.

Spice simulation results using 0.18 CMOS technology model from MOSIS are included together with detailed comparison tables to demonstrate the differences between MOS-C KHN circuits using both of the commercially available active building blocks and CMOS integrated building blocks. A comparison with the Gm-C KHN circuit is also included.
GA-BASED TIME SERIES MODELS WITH THRESHOLD IN TWO DOMAINS
Authors: SU MING , YEN GARY G. , RHINEHART R. R.
Published: June 2009

A new threshold time series model is proposed whose submodels are extended from AR to SARIMA and whose domains having thresholds are extended to two. By these two extensions, the newly proposed models offer more flexibility to piecewisely approximate nonstationary time series by a finite number of local stationary models. A genetic algorithm is applied to simultaneously search for appropriate model structures, estimate the optimal model coefficients, as well as partition space by finding appropriate thresholds. The resulting model is applied to a synthetic multi-frequency sine wave and two financial time series with improved modeling quality. The proposed model is also applied to seismogram analysis in order to recognize earthquake wave pattern related to locate arrival time of different waves.
TEMPERATURE DEPENDENCIES OF CONDUCTIVITY OF MULTI-WALLED CARBON NANOTUBES AND ONION-LIKE CARBON IN DIFFERENT GASEOUS MEDIUM
Authors: BURYAKOV T. I. , ROMANENKO A. I. , ANIKEEVA O. B. , TKACHEV E. N. , KUZNETSOV V. L. , USOLTSEVA A. N. , MOSEENKOV S. I. , MAZOV I. N. , ISCHENKO A. V.
Published: June 2009

We measured the conductivity of multi-walled carbon nanotubes (MWNTs) and onion-like carbon (OLC) in different gaseous media: helium, air, oxygen, hydrogen and methane. The MWNTs had different mean outer diameters varied from 5 to 15 nm. The OLC was synthesized at 1400–1850 K. The adsorption of nitrogen, oxygen, hydrogen and methane leads to decrease of conductivity because these gases are the donors of electron for semi-metallic band structure of investigated objects.
INFLUENCE OF DEAGGLOMERATION STATES OF CARBON NANOTUBES ON THE THERMAL AND MECHANICAL PROPERTIES OF CARBON NANOTUBE-REINFORCED POLYETHYLENE OXIDE
Authors: NARH KWABENA A. , AGWEDICHAM AHMED-TIJANI , JALLO LAILA J. , RHEE KYONG Y. , LEE JI H.
Published: June 2009

Composites of polyethylene oxide and carbon nanotubes were produced by first deagglomerating highly agglomerated multi-walled carbon nanotubes in water, using a high-intensity ultrasonic probe, and then mixing with a solution of the polymer using a high-speed mixer. The deagglomeration of the nanotubes was carried out at different amplitudes of the vibrating ultrasonic probe. Differential scanning calorimetry results show an increase in melting temperature with increase in amplitude of sonication. Also, tensile test results show improved mechanical properties, with increased degree of deagglomeration of the nanotubes. SEM images show that the extent of nanotubes dispersion in the polymer matrix correlates with the extent of deagglomeration.
STUDY OF HYDROGEN STORAGE IN ALUMINUM HYDRIDE COATED SINGLE-WALLED CARBON NANOTUBE
Authors: IYAKUTTI K. , KAWAZOE Y. , RAJARAJESWARI M. , SURYA V. J.
Published: June 2009

In this study, we report the hydrogen storage in aluminum hydride coated single-walled carbon nanotube. All the H 2 adsorption is molecular with H – H bond length of 0.756 Å. The hydrogen storage capacities with half and full coverages are 6.01 (8.3) wt% and 7.2 (10.3) wt%, respectively, without (with) H 3 of AlH 3. At high coverage of AlH 3 ( C 10 AlH 3) interesting clustering/ dimerization of AlH 3 is observed. These systems are quite stable and the H 2 can be extracted from the system without disturbing the C – Al bonding or detaching the AlH 3 from the carbon nanotube. This present study on a full molecular adsorption of hydrogen via light metal-hydride AlH 3 is new and it leads to a practically viable hydrogen storage process.
SEMICONDUCTOR NANOPARTICLES AS REPORTERS IN MULTIPLEXED IMMUNOASSAY AND CELL ANALYSIS
Authors: DUBROVSKY TIM
Published: June 2009

The development of new fluorophores has experienced a tremendous advance over the last two decades. Here, we discuss the photophysical properties of traditional fluorescent labels and the comparatively advantageous properties of quantum dots. The unique spectral properties of quantum dots, such as their large Stokes shifts and exceptional brightness, make them attractive probes in biological applications and prime candidates for further research and development in the field of solid-phase immunoassay and cell analysis.
PHOTOLUMINESCENCE AND TEMPERATURE-DEPENDENT EMISSION STUDIES OF Au25 CLUSTERS IN THE SOLID STATE
Authors: SHIBU EDAKKATTUPARAMBIL S. , PRADEEP THALAPPIL
Published: June 2009

Effect of ligand exchange on the optical and photoluminescence properties of Au 25 SG 18 ( SG -glutathione thiolate) clusters was investigated. A fluorescein-based dye, 5-((2-(and-3)-S-(acetylmercapto)succinoyl)amino)-fluorescein (SAMSA) was anchored on water soluble Au 25 SG 18 clusters by the place exchange reaction and the solid-state emission of the exchange product was studied. Inherent fluorescence image of these clusters was mapped. Organic soluble Au 25( SC 2 H 4 Ph 18 clusters were synthesized as a model system which also showed temperature-dependent solid-state emission, in good agreement with the results from water soluble Au 25 clusters.
ELECTRONIC STRUCTURES OF NAKED AND MOLECULAR ENCAPSULATED Au NANOPARTICLES
Authors: YAMASHITA Y. , HE S. , YOSHIKAWA H. , UEDA S. , KOBAYASHI K. , LOHMÜLLER T. , SPATZ J. P.
Published: June 2009

Naked and molecular encapsulated Au nanoparticles with a diameter of 3 nm were prepared on top of Si in order to elucidate the effect of the molecules on the electronic structures of Au nanoparticles. We have found that the naked particles showed the finite densities of states at the Fermi level while the molecular encapsulated particles exhibited the edge being away from the Fermi level, indicating that the naked and molecular encapsulated Au particles should show metallic and nonmetallic features, respectively. Furthermore, because the naked Au nanoparticles became nonmetallic upon the particles adsorbing the molecules, the highly occupied states of the molecules might be hybridized with the valence states of Au particles, resulting in nonmetallic properties of the molecular encapsulated nanoparticles in the present system.
ONE-POT SYNTHESIS OF HYDROPHILIC AND HYDROPHOBIC FERROFLUID
Authors: MAITY DIPAK , DING JUN , XUE JUN-MIN
Published: June 2009

High-quality hydrophobic or hydrophilic ferrofluid based on magnetite ( Fe 3 O 4) nanoparticles can be synthesized by one-pot direct synthesis which involves thermolysis of Iron(III) acetylacetonate, Fe ( acac )3 in hydrophobic or hydrophilic stabilizing agent, respectively. The structure of the nanoparticles dispersed in the ferrofluid was studied using XRD, FTIR, XPS, and TGA analysis, while morphology and size of the nanoparticles were determined by TEM. The magnetic properties of the samples were measured using VSM and SQUID measurement. The results show that oleylamine (OM) and tri(ethylene glycol) (TREG) coated Fe 3 O 4 nanoparticles which are well stabilized in hydrophobic and hydrophilic ferrofluid, respectively, are relatively monodisperse, single crystalline and superparamagnetic in nature with the blocking temperature at around 100 K.
THE EFFECT OF THE DIAMETER ON THE SPECIFIC HEAT OF CARBON NANOTUBES
Authors: JAFARI MAHMOUD , VAEZZADEH MAJID , OSKOEI LEILA BOHLOLI
Published: June 2009

Specific heat of carbon nanotube (CNT) is affected by its diameter. Increasing of the CNTs diameter increases its specific heat. This phenomenon is due to transversal acoustic phonon modes. The contribution to specific heat from TA modes varies linearly with temperature and becomes saturated after specific temperature. In this paper, the effect of CNTs diameter on the specific heat is theoretically simulated. The result indicates that transversal phonon modes play an important role in the increasing of specific heat with respect to the diameter.
A STUDY ON THE INDIUM-INDUCED VARIATIONS IN PHOTOLUMINESCENCE PROPERTIES OF INDIUM-DOPED ZINCOXIDE NANORODS
Authors: JUNG M. N. , KOO J. E. , CHANG J. H. , JEON T.-I. , LEE W. J. , PARK S. H. , PARK J. S. , HA J. S. , YAO T.
Published: June 2009

In doped ZnO nanorods ( ZnO : In NRs) were grown on Si (111) substrates by using AuGe as a catalyst. In-concentration was controlled as high as 0.33 at.%. The length L to diameter D relationship of NRs revealed that the growth mechanism should be explained in terms of not a simple vapor–liquid–solid (VLS) mechanism but a diffusion-induced growth model. In-induced changes have been investigated from the viewpoint of photoluminescence (PL) property. At room temperature, an increase of extrinsic carrier concentration and interaction with excitons were estimated from the blueshift of peak position and decrease of luminescence intensity. Also, narrow linewidth of low-temperature PL spectra characterized the high structural quality of ZnO : In NRs. We have assigned several PL lines and confirmed the assignment by using excitation power and temperature dependence PL. Considerable evidence of crystal quality degradation was not observed from both measurements; however, we could observe that a defect and donor-bound-exciton complex dominate the PL spectrum. ZnO : In NRs shows good optical quality within our experimental range, and this result strongly supports the feasibility of In -doping to enhance the electrical property of ZnO -based nanostructure.
ATOMISTIC SIMULATION OF GATE EFFECT ON NANOSCALE INTRINSIC Si FIELD-EFFECT TRANSISTORS
Authors: WANG X. F. , ZHAO L. N. , YAO Z. H. , HOU Z. F. , YEE M. , ZHOU X. , LIN S. H. , LEE T. S.
Published: June 2009

We study the electrostatic and quantum transport properties of nanoscale double-gated Si -based field effect transistors within the framework of density functional theory combined with nonequilibrium Green's function approach. In our model device system, a Si slab is sandwiched between two insulator slabs and connected to two semi-infinite Si electrodes at its left and right ends. The effect of the double gates is taken into account by applying proper electrostatic boundary conditions and solving the Poisson equation self-consistently in the system. In the representation of localized SIESTA linear combination of atomic orbitals, the study is carried out with the help of Atomistix ToolKit (ATK) package together with an efficient multigrid Poisson solver. We find that the surface potential versus gate voltage curve shows similar characteristics as in conventional MOSFETs even for devices of 1 nm size, though the shape of the curve varies with the shrink of the system. In different working regimes of the devices, the electrostatic potential and the transmission spectrum are analyzed for an atomistic understanding of the device behavior.
DIRECT IMPRINTING OF SiO2 WAVEGUIDE STRUCTURES ON GaAs AND ITS APPLICATION IN InAs/GaAs QUANTUM DOT INTERMIXING
Authors: CHIA C. K. , SURYANA M. , ZHAO W. , LOW H. Y. , HOPKINSON M.
Published: June 2009

A novel approach for intermixing of InAs / GaAs quantum dot (QD) structure by direct imprinting of SiO 2 strips using silicafilm is presented. The silicafilm SiO 2 strips were imprinted on a InAs / GaAs QD structure by an Obducat nanoimprinter using a polyethylene terepthalate soft mold. Inductively coupled plasma etching of GaAs waveguide structures using the imprinted SiO 2 strips as hard mask has been demonstrated. By using the silicafilm SiO 2 as a capping layer, the effects of impurity-free vacancy disordering intermixing on optical characteristics of the InAs / GaAs QD structure have been examined. The measured photoluminescence spectra of the InAs / GaAs QD structure suggest that differential wavelength blueshift of up to 105 nm for region with and without the SiO 2 film can be achieved. A cost effective one step SiO 2 hard mask with graded thickness profile for quantum well or QD intermixing by imprinting technique is proposed for application in broadband lasers and superluminescent diodes.
MODULATION OF THE PHYSICOCHEMICAL PROPERTIES OF CHITOSAN NANOPARTICLES FOR OPTIMUM DELIVERY OF PLASMID DNA THROUGH GILL MUCOSA
Authors: SHARMA VIMAL KUMAR , MUTREJA ISHA , MITRA SUSMITA
Published: June 2009

The gill mucosa is a convenient route for the administration of DNA vaccine to fish and other aquatic organisms. Nanocarriers have been considered for delivery; however, a suitable formulation is required. To devise an appropriate carrier, we have synthesized chitosan nanoparticles entrapping pDNA at N/P ratios of 1:1 and 2.5:1, using ionic gelation and microemulsion (μE) methods. For nanoparticle characterization, the size, morphology, zetapotential, and IR spectra were determined. The efficiency of pDNA entrapment was established by gel retardation assay. On the basis of the investigations, the loaded nanoparticles synthesized by μE method appear to have the required characteristics for effective delivery by this route.
PREPARATION AND CHARACTERIZATION OF F-DOPED SnO2 NANO-THIN FILMS DEPOSITED ON PET SUBSTRATES
Authors: SHAO LE-XI , ZHANG JUN , XUE SHU-WEN , LIU XIAO-PING
Published: June 2009

Tin oxide doped with fluorine ( SnO 2: F ) thin films were deposited on polyethylene terephthalate (PET) foils by RF reaction cosputtering at low temperature in different oxygen partial pressures. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) were used to study the effects of the processing parameters on the crystallization and surface topography of the as-prepared SnO 2 films. The results showed that high quality SnO 2: F thin films could be obtained by optimizing deposition conditions without intentional annealing, i.e. oxygen partial pressure to total pressure of higher than 50%, RF power higher than 50 W. The optical transmittance measurements revealed that the SnO 2: F films were highly transparent in the visible region (90%) and showed an absorption edge redshift with increasing oxygen partial pressure from 1/4 to 3/4. The optical bandgap energy was calculated to be about 3.6 eV. Hall effect measurements confirmed that the as-prepared SnO 2 thin films possessed good electrical properties with a low resistivity of 10-3 Ω · cm, a high carrier concentration of 9.6 × 1018 cm-3, and a Hall mobility of about 200 cm2/V · s.
DEVELOPMENT AND CHARACTERIZATION OF A NANOCARRIER FOR QUERCETIN
Authors: WONG MAN-YI , CHIU GIGI N. C.
Published: June 2009

Quercetin is a naturally occurring cytotoxic compound where clinical use has been limited by its low water solubility. Therefore, liposomes were explored for solubilizing quercetin. Liposomes composed of DPPC (1,2 dipalmitoyl-sn-glycerol-3-phosphocholine)/DSPE-PEG2000(1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)2000])/quercetin (90:5:5 mole ratio) incorporated quercetin efficiently at 100.9 ± 4.6% and increased quercetin concentration in water 11.2-fold. Stability studies at storage temperature of 4°C showed that the liposomes were stable for up to 16 weeks, without any significant changes in diameters. Liposomal quercetin showed a delayed release profile and reduced quercetin degradation. In vitro cytotoxicity tests also showed that the ED50of liposomal quercetin was 17.6 times lower than free quercetin in MDA-MB-231 breast cancer cells. In conclusion, the DPPC/DSPE-PEG-based liposomes were stable and were capable of solubilizing quercetin, preventing quercetin degradation, and increasing quercetin in vitro cytotoxicity. Hence, liposomes are a suitable nanocarrier for quercetin.
Improved Monolingual Hypothesis Alignment for Machine Translation System Combination
Authors: He Xiaodong , Yang Mei , Gao Jianfeng , Nguyen Patrick , Moore Robert
Published: June 2009

This article presents a new hypothesis alignment method for combining outputs of multiple machine translation (MT) systems. An indirect hidden Markov model (IHMM) is proposed to address the synonym matching and word ordering issues in hypothesis alignment. Unlike traditional HMMs whose parameters are trained via maximum likelihood estimation (MLE), the parameters of the IHMM are estimated indirectly from a variety of sources including word semantic similarity, word surface similarity, and a distance-based distortion penalty. The IHMM-based method significantly outperforms the state-of-the-art, TER-based alignment model in our experiments on NIST benchmark datasets. Our combined SMT system using the proposed method achieved the best Chinese-to-English translation result in the constrained training track of the 2008 NIST Open MT Evaluation.
Discriminative Machine Translation Using Global Lexical Selection
Authors: Venkatapathy Sriram , Bangalore Srinivas
Published: June 2009

Statistical phrase-based machine translation models crucially rely on word alignments. The search for word-alignments assumes a model of word locality between source and target languages that is violated in starkly different word-order languages such as English-Hindi. In this article, we present models that decouple the steps of lexical selection and lexical reordering with the aim of minimizing the role of word-alignment in machine translation. Indian languages are morphologically rich and have relatively free-word order where the grammatical role of content words is largely determined by their case markers and not just by their positions in the sentence. Hence, lexical selection plays a far greater role than lexical reordering. For lexical selection, we investigate models that take the entire source sentence into account and evaluate their performance for English-Hindi translation in a tourism domain.
Risks to the public
Authors: Neumann Peter G.
Published: June 2009

Edited by Peter G. Neumann (Risks Forum Moderator and Chairman of the ACM Committee on Computers and Public Policy), plus personal contributions by others, as indicated. Opinions expressed are individual rather than organizational, and all of the usual disclaimers apply. We address problems relating to software, hardware, people, and other circumstances relevant to computer systems. To economize on space, we include pointers to items in the online Risks Forum: (R i j) denotes RISKS vol i number j. Cited RISKS items generally identify contributors and sources, together with URLs. Official RISKS archives are available at www.risks.org (which redirects to Newcastle and gets you nice html formatting and a search engine courtesy of Lindsay Marshall; http://catless.ncl.ac.uk/Risks/i.j.html gets you (R i j)) and at ftp://www.sri.com/risks.
Evaluation of object-oriented spatial complexity measures
Authors: Chhabra Jitender Kumar , Gupta Varun
Published: June 2009

Spatial complexity measures help in the estimation of the effort re-quired in the process of program comprehension. These spatial com-plexity measures have been proposed for procedure-oriented software as well as object-oriented software. In this paper, an at-tempt has been made to evaluate object-oriented spatial complexity measures using formal evaluation frameworks proposed by Weyu-ker and Briand et al. A practical and useful complexity measure must satisfy most of the properties given in these frameworks. The results of this study show that object-oriented spatial metrics satisfy all properties and parameters required by these two evaluation frameworks and thus these spatial measures are robust and useful.
Generalized coupling measure for aspect-oriented systems
Authors: Kumar Avadhesh , Kumar Rajesh , Grover P. S.
Published: June 2009

Coupling is an internal software attribute that can be used to indicate the degree of interdependence among the components of a software system. Coupling in software has been linked to predict external software quality attributes such as
fault-proneness, ripple effects, changeability, impact analysis
etc. Despite an interesting body of work for measuring coupling in Aspect-Oriented (AO) Systems, there is no complete generic coupling framework for AO systems. In this paper, we have proposed a generic coupling measurement framework that takes into account three, the most well known families of Aspect-Oriented Programming (AOP) languages, AspectJ, CaesarJ and Hyper/J. This paper contributes to an enhanced understanding of coupling in AO systems, which in turn helps to (i) define new coupling metrics which permit the analysis and comparison of Java, AspectJ, CaesarJ and Hyper/J implementations, and (ii) integrate different existing measures and examine same concepts from different perspectives.
Enhanced inquiry method for malicious object identification
Authors: Saini Dinesh Kumar , Yousif Jabar H. , Omar Wail M.
Published: June 2009

This paper proposes a new technique for malicious object detec-tion and identification. The technique is based on a concept of vi-rus inquiry. The inquiry is an activity that is performed by the malicious object during its initiation. The malicious object uses this activity to ensure its uniqueness in memory. The inquiry can be regarded as a common behavior of malicious object such as viruses. The proposed system is designed using the concept of Ob-ject Oriented Programming (OOP) that treats the operating system, user program, and virus as objects. It is constructed of three ele-mentary objects that perform their activities depending on two da-tabases.
Delegation
Authors: Yang Qun , Xu Man-Wu , Pi De-Chang
Published: June 2009

Due to the growing complexity of computing systems, and the increasing demand for high availability and reliability of them, adapting software at runtime is becoming more and more important. However, there is not sufficient support for dynamic software adaptation at the level of programming languages. In this paper, we investigate a language feature, namely delegation, to argue that delegation is a favorite choice to deal with dynamic software adaptation. To do that, we present Φ calculus, which is an imperative object-based calculus with delegation, to model essential features of languages, with focusing on how to incorporate delegation into programming languages to support dynamic software adaptation. We give the operational semantics of Φ calculus. We also state how delegation is used in object extending and method sharing between objects. We conclude that delegation makes dynamic software adaptation simpler and more flexible.
Methods for power optimization in SOC-based data flow systems
Authors: Grosse Philippe , Durand Yves , Feautrier Paul
Published: June 2009

Whereas the computing power of DSP or general-purpose processors was sufficient for 3G baseband telecommunication algorithms, stringent timing constraints of 4G wireless telecommunication systems require computing-intensive data-driven architectures. Managing the complexity of these systems within the energy constraints of a mobile terminal is becoming a major challenge for designers. System-level low-power policies have been widely explored for generic software-based systems, but data-flow architectures used for high data-rate telecommunication systems feature heterogeneous components that require specific configurations for power management. In this study, we propose an innovative power optimization scheme tailored to self-synchronized data-flow systems. Our technique, based on the synchronous data-flow modeling approach, takes advantage of the latest low-power techniques available for digital architectures. We illustrate our optimization method on a complete 4G telecommunication baseband modem and show the energy savings expected by this technique considering present and future silicon technologies.
Generating realistic stimuli for accurate power grid analysis
Authors: Morgado P. Marques , Flores Paulo F. , Silveira L. Miguel
Published: June 2009

Power analysis tools are an integral component of any current power sign-off methodology. The performance of a design's power grid affects the timing and functionality of a circuit, directly impacting the overall performance. Ensuring power grid robustness implies taking into account, among others, static and dynamic effects of voltage drop, ground bounce, and electromigration. This type of verification is usually done by simulation, targeting a worst-case scenario where devices, switching almost simultaneously, could impose stern current demands on the power grid. While determination of the exact worst-case switching conditions from the grid perspective is usually not practical, the choice of simulation stimuli has a critical effect on the results of the analysis. Targetting safe but unrealistic settings could lead to pessimistic results and costly overdesigns in terms of die area. In this article we describe a software tool that generates a reasonable, realistic, set of stimuli for simulation. The approach proposed accounts for timing and spatial restrictions that arise from the circuit's netlist and placement and generates an approximation to the worst-case condition. The resulting stimuli indicate that only a fraction of the gates change in any given timing window, leading to a more robust verification methodology, especially in the dynamic case. Generating such stimuli is akin to performing a standard static timing analysis, so the tool fits well within conventional design frameworks. Furthermore, the tool can be used for hotspot detection in early design stages.
High-performance obstacle-avoiding rectilinear steiner tree construction
Authors: Liu Chih-Hung , Yuan Shih-Yi , Kuo Sy-Yen , Wang Szu-Chi
Published: June 2009

Rectilinear Steiner trees are used to route signal nets by global and detail routers in VLSI design for a long time. However, in current IC industry, there are significantly increasing obstacles to be considered, such as large-scale power networks, pre-routed nets, IP blocks, and antenna jumpers. Accordingly, the
obstacle-avoiding rectilinear Steiner minimal tree
(OARSMT) problem has become more important. In this article, we propose a new routing graph,
obstacle-avoiding routing graph
(OARG), for the OARSMT problem. Due to the important properties of OARG, we construct a 3-step algorithm and a local refinement scheme, which both can take advantage of these properties, to find a suboptimal solution efficiently. Furthermore, each step of our 3-step algorithm as well as the local refinement scheme has theoretical or practical benefits. Therefore, each of them can be applicable to other existing works for general or specific considerations such as efficiency or effectiveness. Extensive experimental results show that our method outperforms all existing works in terms of wirelength and achieves the best speed performance.
Degradation of Activated Protein Kinases by Ubiquitination
Authors: Zhimin Lu , Tony Hunter
Published: June 2009

Protein kinases are important regulators of intracellular signal transduction pathways and play critical roles in diverse cellular functions. Once a protein kinase is activated, its activity is subsequently downregulated through a variety of mechanisms. Accumulating evidence indicates that the activation of protein kinases commonly initiates their downregulation via the ubiquitin/proteasome pathway. Failure to regulate protein kinase activity or expression levels can cause human diseases.
RNA Polymerase Active Center: The Molecular Engine of Transcription
Authors: Nudler Evgeny
Published: June 2009

RNA polymerase (RNAP) is a complex molecular machine that governs gene expression and its regulation in all cellular organisms. To accomplish its function of accurately producing a full-length RNA copy of a gene, RNAP performs a plethora of chemical reactions and undergoes multiple conformational changes in response to cellular conditions. At the heart of this machine is the active center, the engine, which is composed of distinct fixed and moving parts that serve as the ultimate acceptor of regulatory signals and as the target of inhibitory drugs. Recent advances in the structural and biochemical characterization of RNAP explain the active center at the atomic level and enable new approaches to understanding the entire transcription mechanism, its exceptional fidelity and control.
A Journey in the World of DNA Rings and Beyond
Authors: Wang James C.
Published: June 2009

I was born in China and would have remained there but for the tumultuous events that led many of my generation to the United States for graduate studies. Norman Davidson introduced me to DNA when I became a postdoctoral fellow in his group at the California Institute of Technology in 1964, and a fortuitous conversation there ignited my interest in DNA ring formation, which later led me to study different topological forms of DNA rings—catenanes, knots, and supercoils. In 1968, a chance observation led me to identify a new enzyme capable of converting one DNA ring form to another, an enzyme now known as a DNA topoisomerase. My interest in DNA rings and DNA topoisomerases continued throughout my years at the University of California, Berkeley, and Harvard. The fascinating ability of the topoisomerases in passing DNA strands or double helices through one another and their importance in cellular processes have kept me and many others excited in their studies.
Essentials for ATP Synthesis by F1F0 ATP Synthases
Authors: von Ballmoos Christoph , Wiedenmann Alexander , Dimroth Peter
Published: June 2009

The majority of cellular energy in the form of adenosine triphosphate (ATP) is synthesized by the ubiquitous F1F0 ATP synthase. Power for ATP synthesis derives from an electrochemical proton (or Na+) gradient, which drives rotation of membranous F0 motor components. Efficient rotation not only requires a significant driving force (ΔμH+), consisting of membrane potential (Δψ) and proton concentration gradient (ΔpH), but also a high proton concentration at the source P side. In vivo this is maintained by dynamic proton movements across and along the surface of the membrane. The torque-generating unit consists of the interface of the rotating c ring and the stator a subunit. Ion translocation through this unit involves a sophisticated interplay between the c-ring binding sites, the stator arginine, and the coupling ions on both sides of the membrane. c-ring rotation is transmitted to the eccentric shaft γ-subunit to elicit conformational changes in the catalytic sites of F1, leading to ATP synthesis.
Short Hypoxia Does not Affect Plasma Leptin in Healthy Men under Euglycemic Clamp Conditions
Authors: Schmoller Andre , Voss Michaela , Gehring Hartmut , Rudolf Sebastian , Schweiger Ulrich , Schultes Bernd , Oltmanns Kerstin M.
Published: June 2009

Leptin is involved in the endocrine control of energy expenditure and body weight regulation. Previous studies emphasize a relationship between hypoxic states and leptin concentrations. The aim of this study was to investigate the effects of acute hypoxia on leptin concentrations in healthy subjects. We examined 14 healthy men. Hypoxic conditions were induced by decreasing oxygen saturation to 75% for 30 minutes. Plasma leptin concentrations were determined at baseline, after 3 hours of euglycemic clamping, during hypoxia, and repeatedly the following 2.5 hours thereafter. Our results show an increase of plasma leptin concentrations in the course of 6 hours of hyperinsulinemic‐euglycemic clamping which may reflect diurnal rhythmicity. Notwithstanding, there was no difference between levels of leptin in the hypoxic and the normoxic condition (P = .2). Since we did not find any significant changes in leptin responses upon hypoxia, plasma leptin levels do not seem to be affected by short hypoxic episodes of moderate degree.
One‐Step Synthesis of Pd‐M/ZnO (M=Ag, Cu, and Ni) Catalysts by γ‐Irradiation and Their Use in Hydrogenation and Suzuki Reaction
Authors: Kim Mi-Ran , Choi Seong-Ho
Published: May 2009

ZnO‐supported Pd, Pd‐Ag, Pd‐Cu, and Pd‐Ni catalysts (Pd‐M/ZnO) were prepared in MeOH/H2O mixture (4/1, v/v‐%) by γ‐irradiation at room temperature. Small mono‐ and bimetallic nanoparticles were loaded on the surface of ZnO nanopowder as confirmed with TEM, TEM‐EDXS, XRD, and ICP‐AES data. The catalytic efficiency against Pd‐M/ZnO was determined in hydrogenation and Suzuki reaction and compared with the commercial Pd/C catalyst. The Pd‐Ag/ZnO showed the highest catalytic efficiency in the Suzuki reaction.
A Comparative Study of Three Different Mathematical Methods for Solving the Unit Commitment Problem
Authors: Kurban Mehmet , Başaran Filik Ümmühan
Published: June 2009

The unit commitment (UC) problem which is an important subject in power system engineering is solved by using Lagragian relaxation (LR), penalty function (PF), and augmented Lagrangian penalty function (ALPF) methods due to their higher solution quality and faster computational time than metaheuristic approaches. This problem is considered to be a nonlinear programming‐(NP‐) hard problem because it is nonlinear, mixed‐integer, and nonconvex. These three methods used for solving the problem are based on dual optimization techniques. ALPF method which combines the algorithmic aspects of both LR and PF methods is firstly used for solving the UC problem. These methods are compared to each other based on feasible schedule for each stage, feasible cost, dual cost, duality gap, duration time, and number of iterations. The numerical results show that the ALPF method gives the best duality gap, feasible and dual cost instead of worse duration time and the number of iterations. The four‐unit Tuncbilek thermal plant which is located in Kutahya region in Turkey is chosen as a test system in this study. The programs used for all the analyses are coded and implemented using general algebraic modeling system (GAMS).
FGF-23 Levels before and after Renal Transplantation
Authors: Economidou Domniki , Dovas Spyros , Papagianni Aikaterini , Pateinakis Panagiotis , Memmos Dimitrios
Published: May 2009

Phosphatonin fibroblast growth factor-23 (FGF-23) is involved in phosphate (P) excretion and vitamin D metabolism. Recently, FGF-23 has been suggested to be responsible for the hypophosphatemia and inappropriately low calcitriol levels observed after renal transplantation. We performed a prospective study to investigate FGF-23 levels in patients with end-stage renal disease before and after renal transplantation and their probable association with markers of bone and mineral metabolism. Intact FGF-23 levels were determined before and at 3, 6, and 12 months posttransplantation in 18 renal transplant recipients. Intact parathyroid hormone (iPTH), calcium (Ca), P, 25(OH)VitD, and 1,25VitD levels were measured at the same time periods. Renal threshold phosphate concentration (/GFR) was also calculated at 3, 6, and 12 months posttransplantation. The results showed that FGF-23 levels decreased by 89% 3 months posttransplantation (346 146 versus 37 9 pg/mL, ) and remained stable throughout the study period. iPTH and P levels also decreased significantly after renal transplantation, while Ca and 1,25VitD increased. Pretransplantation FGF-23 was significantly correlated with P levels at 3 months posttransplantation (). In conclusion, FGF-23 levels decrease dramatically after successful renal transplantation. Pre-transplantation FGF-23 correlate with P levels 3 months posttransplantation.
Efficient siRNA Delivery by the Cationic Liposome DOTAP in Human Hematopoietic Stem Cells Differentiating into Dendritic Cells
Authors: Martino Sabata , di Girolamo Ilaria , Tiribuzi Roberto , D′Angelo Francesco , Datti Alessandro , Orlacchio Aldo
Published: May 2009

RNA interference technology is an ideal strategy to elucidate the mechanisms associated with
human CD34+ hematopoietic stem cell differentiation into dendritic cells. Simple manipulations in
vitro can unequivocally yield alloreactive or tolerogenic populations, suggesting key implications of
biochemical players that might emerge as therapeutic targets for cancer or graft‐versus‐host disease.
To knockdown proteins typically involved in the biology of dendritic cells, we employed an
siRNA delivery system based on the cationic liposome DOTAP as the carrier. Freshly‐isolated CD34+ cells were transfected with siRNA for cathepsin S with negligible cytotoxicity and transfection rates
(>60%) comparable to the efficiency shown by lentiviral vectors. Further, cathepsin S knockdown was performed during both cell commitment and through the entire 14‐day differentiation process with
repeated transfection rounds that had no effect per se on cell development. Tested in parallel, other commercially‐available chemical reagents failed to meet acceptable standards.
In addition to safe and practical handling, a direct advantage of DOTAP over viral‐mediated
techniques is that transient silencing effects can be dynamically appraised through the recovery of
targeted proteins. Thus, our findings identify DOTAP as an excellent reagent for gene silencing in
resting and differentiating CD34+ cells, suggesting a potential for applications in related preclinical
models.
A New Extension Theorem for Concave Operators
Authors: Peng Jian-wen , Rong Wei-dong , Yao Jen-Chih
Published: May 2009

We present a new and interesting extension theorem for concave operators as follows. Let "Equation missing" be a real linear space, and let "Equation missing" be a real order complete PL space. Let the set "Equation missing" be convex. Let "Equation missing" be a real linear proper subspace of "Equation missing", with "Equation missing", where "Equation missing" for some "Equation missing". Let "Equation missing" be a concave operator such that "Equation missing" whenever "Equation missing" and "Equation missing". Then there exists a concave operator "Equation missing" such that (i) "Equation missing" is an extension of "Equation missing", that is, "Equation missing" for all "Equation missing", and (ii) "Equation missing" whenever "Equation missing".