cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Strong charge carrier confinement in purely strain induced GaAs/InAlAs single quantum wires
Creators: name: Schuster, Robert
name: Hajak, H.
name: Reinwald, Matthias
name: Wegscheider, Werner
name: Schuh, Dieter
name: Bichler, Max
name: Abstreiter, Gerhard
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: gallium arsenide, indium compounds, aluminium compounds, III-V semiconductors, molecular beam epitaxial growth, semiconductor growth, semiconductor quantum wires, photoluminescence, excitons, internal stresses, semiconductor quantum wells
subject: 530 Physik
subject: 81.07.Vb; 73.21.Hb; 81.05.Ea; 78.67.Lt; 78.67.De; 78.55.Cr; 81.15.Hi

description: We report on micro-photoluminescence studies of single quantum wires which were grown by molecular beam epitaxy. Employing the cleaved edge overgrowth technique, quantum wires located in an overgrown (011) oriented GaAs quantum well originate purely from the tensile strain field of InAlAs layers grown along the [100] direction. These stressor layers are separated by 1-µm-wide AlGaAs barriers so that the photoluminescence signals of different quantum wires can be resolved individually. Their confinement energy varies systematically with the widths of the stressor and overgrown layers, reaching values as high as 51.5 meV. The quantum wire signals are characterized by a smooth line shape even for the lowest excitation powers, indicating the absence of pronounced exciton localization.
Electronic and phononic properties of the chalcopyrite CuGaS2
Creators: name: Romero, A. H.
name: Cardona, M.
name: Kremer, R. K.
name: Lauck, R.
name: Siegle, G.
name: Hoch, C.
name: Munoz, A.
name: Schindler, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The availability of ab initio electronic calculations and the concomitant techniques for deriving the corresponding lattice dynamics have been profusely used for calculating thermodynamic and vibrational properties of semiconductors, as well as their dependence on isotopic masses. The latter have been compared with experimental data for elemental and binary semiconductors with different isotopic compositions. Here we present theoretical and experimental data for several vibronic and thermodynamic properties of CuGa2, a canonical ternary semiconductor of the chalcopyrite family. Among these properties are the lattice parameters, the phonon dispersion relations and densities of states (projected on the Cu, Ga, and S constituents), the specific heat and the volume thermal expansion coefficient. The calculations were performed with the ABINIT and VASP codes within the LDA approximation for exchange and correlation and the results are compared with data obtained on samples with the natural isotope composition for Cu, Ga and S, as well as for isotope enriched samples.
description: 9 pages, 8 Figures, submitted to Phys. Rev B
Patient Perspectives on Uncertainty in Genomic Medicine
Creators: name: Halverson, Colin
Publisher: name: Center for ELSI Resources and Analysis
Year: 2023
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Ethics
subject: Science
subject: ELSI
subject: variants of uncertain significance
subject: incidental findings
subject: patient experience
subject: clinical decision making

description: Empirical studies of patients’ experiences when receiving uncertain genetic information have revealed wide-ranging, and often contradictory, psychosocial responses—positive, negative, and neutral. In any case, longitudinal studies typically suggest that patient affect soon returns to baseline. Findings about patients’ ability to recall and comprehend uncertainty also vary across studies, although the overall impression is that with appropriate counseling, and in emotionally calm conditions, levels of both variables are acceptable for patients to engage in ethically sound decision-making. The variability in the results of these empirical studies may in part be due to a presupposition that uncertainty must be reduced or eliminated. As has been outlined above, though, uncertainty is simultaneously an intrinsic feature of (genomic) medicine and a potentially desirable outcome, with benefits of its own. A shift in counseling practice towards the management of uncertainty is therefore preferable and already underway.
Water-soluble substituted chitosan derivatives as technology platform for inhalation delivery of siRNA
Creators: name: Capel, Victoria
name: Vllasaliu, Driton
name: Watts, Peter
name: Clarke, Philip A.
name: Luxton, Dominic
name: Grabowska, Anna M.
name: Mantovani, Giuseppe
name: Stolnik, Snjezana
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biophysics
subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Cancer

description: Despite research efforts full potential of siRNA-based therapeutics has not yet been fully realized due to a need for suitable, effective delivery formulations. Here, we examine a potential of a new class of water-soluble chitosans as siRNA platform for pulmonary delivery. The system is based on piperazine-substituted chitosans, a material designed to integrate established, safe application of chitosan for mucosal administration with novel properties: the piperazine-substituted chitosans are freely water-soluble at physiological pH, possess low cytotoxicity (no significant reduction in cell viability up to 0.1 mg/ml), and provide efficient incorporation of siRNA into sub-300 nm colloidal complexes (at relatively low polymer/siRNA ratio of 5:1). In vitro, the complexes achieved silencing of a model gene at a level of 40–80%, when tested in a panel of lung epithelial cells. Considering the formulation ‘developability’, there were no significant changes in the complexes’ size and integrity on aerosolisation by microsprayer (PenCentury™) device. Following intratracheal aerolisation, the complexes deposited throughout the lung, although relatively inhomogeneously, as judged from IVIS imaging of the isolated mouse lung (visualizing DY647-siRNA). In vivo data illustrate absence of adverse effects on repeated administration of complexes and significant tumor reduction in atopical lung cancer model in mice. Altogether, the data illustrates potential of substituted chitosan derivatives to be utilized as a safe system for inhalation delivery of siRNA.
Multifunctional nanoemulsions for intraductal delivery as a new platform for local treatment of breast cancer
Creators: name: Migotto, Amanda
name: Carvalho, Vanessa F. M.
name: Salata, Giovanna C.
name: da Silva, Fernanda W. M.
name: Yun Irene Yan, Chao
name: Ishida, Kelly
name: Costa-Lotufo, Leticia V.
name: Steiner, Alexandre A.
name: Lopes, Luciana B.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Biochemistry
subject: Medicine
subject: Molecular Biology
subject: Pharmacology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Cancer

description: Considering that breast cancer usually begins in the lining of the ducts, local drug administration into the ducts could target cancers and pre-tumor lesions locally while reducing systemic adverse effects. In this study, a cationic bioadhesive nanoemulsion was developed for intraductal administration of C6 ceramide, a sphingolipid that mediates apoptotic and non-apoptotic cell death. Bioadhesive properties were obtained by surface modification with chitosan. The optimized nanoemulsion displayed size of 46.3 nm and positive charge, properties that were not affected by ceramide encapsulation (0.4%, w/w). C6 ceramide concentration necessary to reduce MCF-7 cells viability to 50% (EC50) decreased by 4.5-fold with its nanoencapsulation compared to its solution; a further decrease (2.6-fold) was observed when tributyrin (a pro-drug of butyric acid) was part of the oil phase of the nanocarrier, a phenomenon attributed to synergism. The unloaded nanocarrier was considered safe, as indicated by a score <0.1 in HET-CAM models, by the high survival rates of Galleria mellonella larvae exposed to concentrations ≤500 mg/mL, and absence of histological changes when intraductally administered in rats. Intraductal administration of the nanoemulsion prolonged drug localization for more than 120 h in the mammary tissue compared to its solution. These results support the advantage of the optimized nanoemulsion to enable mammary tissue localization of C6 ceramide.
Long relaxation times of holes in Si/SiGe quantum cascade structures with a diagonal intersubband transition
Creators: name: Bormann, I.
name: Brunner, K.
name: Hackenbuchner, S.
name: Riedl, H.
name: Schmult, Stefan
name: Wegscheider, Werner
name: Abstreiter, Gerhard
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: Si; SiGe; Electroluminescence; Quantum cascade; Phonon scattering
subject: 530 Physik
subject: 78.66.Db; 78.60.−b; 78.67.Pt; 72.10.Di

description: In this work we investigate experimentally and theoretically the feasibility to enhance the nonradiative lifetime of the upper heavy hole state in Si/SiGe quantum cascade (QC) structures within a diagonal transition design. The problem of fast nonradiative optical phonon scattering makes it impossible to achieve population inversion with recently demonstrated Si/SiGe QC mid-infrared emitter structures, which use vertical transitions between the first two heavy hole states in a single quantum well. We will show that it is possible to prolong the upper state lifetime by more than an order of magnitude in a diagonal transition active region design, that uses transitions between heavy hole ground states of spatially separated quantum wells. Our experimental findings derived from electroluminescence measurements are in good agreement with calculated values based on a 6-band k·p model.
Graphene transistors are insensitive to pH changes in solution
Creators: name: Fu, Wangyang
name: Nef, Cornelia
name: Knopfmacher, Oren
name: Tarasov, Alexey
name: Weiss, Markus
name: Calame, Michel
name: Schönenberger, Christian
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We observe very small gate-voltage shifts in the transfer characteristic of as-prepared graphene field-effect transistors (GFETs) when the pH of the buffer is changed. This observation is in strong contrast to Si-based ion-sensitive FETs. The low gate-shift of a GFET can be further reduced if the graphene surface is covered with a hydrophobic fluorobenzene layer. If a thin Al-oxide layer is applied instead, the opposite happens. This suggests that clean graphene does not sense the chemical potential of protons. A GFET can therefore be used as a reference electrode in an aqueous electrolyte. Our finding sheds light on the large variety of pH-induced gate shifts that have been published for GFETs in the recent literature.
Relativistic mechanics in a general setting
Creators: name: Sardanashvily, G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Relativistic mechanics on an arbitrary manifold is formulated in the terms of jets of its one-dimensional submanifolds. A generic relativistic Lagrangian is constructed. Relativistic mechanics on a pseudo-Riemannian manifold is particularly considered.
description: 15 pages
A comparative assessment of deformation characteristics of self-expanding venous stents
Creators: name: Hejazi, Masoud
Publisher: name: University of British Columbia
Year: 2018

description: Stents are medical devices that are widely used to treat vascular diseases through endovascular surgery. This minimally invasive surgery provides a faster recovery and fewer complications in comparison to other types of treatments. This device is available in various sizes and designs for deployment in a variety of blood vessels. The deformation characteristics of a stent contribute in a successful stent deployment and its long-term performance. A particular vascular disease and its location in the blood circulatory system require a stent with certain deformation characteristics. Accordingly, by studying these parameters for different stent designs, we can identify the most suitable stent for each type of disease. The main objective of this thesis is to develop an analytical method that predicts the deformation characteristics of self-expanding venous stents. The presented analytical method in this thesis is desirable for design, optimization and comparative assessments with less computation time and cost in comparison to finite element simulation. The unit-cell study forms the framework of the presented analytical method, which allows the analysis of the radial pressure, compliance, and foreshortening. The developed analytical method relies on two critical stages: 1. Defining the deformation characteristics in terms of unit-cell deformation mechanism, 2. Correlating unit-cell deformation mechanism to strut bending mechanics. These two stages are respectively validated through axisymmetric FE simulation and unit-cell FE simulation. The precision and accuracy of the method were found acceptable. Collapse, another critical deformation mode, was studied through the axisymmetric FE simulation. The structural instability and compliance contribute to the collapse deformation. Four different venous stent designs (Cook Vena, Cook Z, Luminexx, and Wallstent) are evaluated in terms of collapse, foreshortening, radial pressure, and compliance. Steel stents (Cook Z and Wallstent) are less compliant than Nitinol stents (Luminexx and Wallstent) and are more reliable to treat localized blood clots. The Nitinol stents are more efficient to be deployed close to body joints. Luminexx and Wallstent apply larger radial pressure and are the most reasonable choices for vital veins. If the final length of stent is critical (e.g. deployment close to branch orifice), Cook Z can be the best choice.
The Star Formation History in The Far Outer Disc of M33
Creators: name: Barker, M. K.
name: Ferguson, A. M. N.
name: Cole, A. A.
name: Ibata, R.
name: Irwin, M.
name: Lewis, G. F.
name: Smecker-Hane, T. A.
name: Tanvir, N. R.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The outer regions of disc galaxies are becoming increasingly recognized as key testing sites for models of disc assembly and evolution. Important issues are the epoch at which the bulk of the stars in these regions formed and how discs grow radially over time. To address these issues, we use Hubble Space Telescope Advanced Camera for Surveys imaging to study the star formation history (SFH) of two fields at 9.1 and 11.6 kpc along M33's northern major axis. These fields lie at ~ 4 and 5 V-band disc scale-lengths and straddle the break in M33's surface brightness profile. The colour-magnitude diagrams (CMDs) reach the ancient main sequence turnoff with a signal-to-noise ratio of ~ 5. From detailed modelling of the CMDs, we find that the majority of stars in both fields combined formed at z < 1. The mean age in the inner field, S1, is ~ 3 +/- 1 Gyr and the mean metallicity is [M/H] ~ -0.5 +/- 0.2 dex. The star formation history of S1 unambiguously reveals how the inside-out growth previously measured for M33's inner disc out to ~ 6 kpc extends out to the disc edge at ~ 9 kpc. In comparison, the outer field, S2, is older (mean age ~ 7 +/- 2 Gyr), more metal-poor (mean [M/H] ~ -0.8 +/- 0.3 dex), and contains ~ 30 times less stellar mass. These results provide the most compelling evidence yet that M33's age gradient reverses at large radii near the disc break and that this reversal is accompanied by a break in stellar mass surface density. We discuss several possible interpretations of this behaviour including radial stellar mixing, warping of the gaseous disc, a change in star formation efficiency, and a transition to another structural component. These results offer one of the most detailed views yet of the peripheral regions of any disc galaxy and provide a much-needed observational constraint on the last major epoch of star formation in the outer disc.
description: 15 pages, 9 figures, accepted to MNRAS, hi-res version available at http://www.roe.ac.uk/~mkb/astroph/m33hires.pdf
Fabrication of a drug delivery system that enhances antifungal drug corneal penetration
Creators: name: Li, Jingguo
name: Li, Zhanrong
name: Liang, Zhen
name: Han, Lei
name: Feng, Huayang
name: He, Siyu
name: Zhang, Junjie
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Computational Biology

description: Fungal keratitis (FK) remains a severe eye disease, and effective therapies are limited by drug shortages and critical ocular barriers. Despite the high antifungal potency and broad spectrum of econazole, its strong irritant and insolubility in water hinder its ocular application. We designed and fabricated a new drug delivery system based on a polymeric vector for the ocular antifungal application of econazole. This novel system integrates the advantages of its constituent units and exhibits superior comprehensive performance. Using the new system, drug content was significantly increased more than 600 folds. The results of in vivo and in vitro experiments demonstrated that the econazole-loaded formulation exhibited significantly enhanced corneal penetration after a single topical ocular administration, excellent antifungal activity, and good tolerance in rabbits. Drug concentrations and ocular relative bioavailability in the cornea were 59- and 29-time greater than those in the control group, respectively. Following the topical administration of one eye drop (50 μL of 0.3% w/v econazole) in fungus-infected rabbits, a high concentration of antimycotic drugs in the cornea and aqueous humor was sustained and effective for 4 h. The mechanism of corneal penetration was also explored using dual fluorescent labeling. This novel drug delivery system is a promising therapeutic approach for oculomycosis and could serve as a candidate strategy for use with various hydrophobic drugs to overcome barriers in the treatment of many other ocular diseases.
Symplectic 4--manifolds with K = 0 and the Lubotzky alternative
Creators: name: Friedl, Stefan
name: Vidussi, Stefano
Publisher: name: arXiv
Year: 2011
Subjects: subject: Geometric Topology (math.GT)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 57R17, 57R57

description: In this paper we use the Lubotzky alternative for finitely generated linear groups to determine which 4-manifolds admitting a free circle action can be endowed with a symplectic structure with trivial canonical class. The content of this paper partly overlaps with the content of the unpublished preprint "Symplectic 4-manifolds with a free circle action" (arXiv:0801.1313 [math.GT]).
description: 7 pages. To appear in Math. Res. Lett
Dirac Strings and Magnetic Monopoles in Spin Ice Dy2Ti2O7
Creators: name: Morris, D. J. P.
name: Tennant, D. A.
name: Grigera, S. A.
name: Klemke, B.
name: Castelnovo, C.
name: Moessner, R.
name: Czternasty, C.
name: Meissner, M.
name: Rule, K. C.
name: Hoffmann, J. -U.
name: Kiefer, K.
name: Gerischer, S.
name: Slobinsky, D.
name: Perry, R. S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: While sources of magnetic fields - magnetic monopoles - have so far proven elusive as elementary particles, several scenarios have been proposed recently in condensed matter physics of emergent quasiparticles resembling monopoles. A particularly simple proposition pertains to spin ice on the highly frustrated pyrochlore lattice. The spin ice state is argued to be well-described by networks of aligned dipoles resembling solenoidal tubes - classical, and observable, versions of a Dirac string. Where these tubes end, the resulting defect looks like a magnetic monopole. We demonstrate, by diffuse neutron scattering, the presence of such strings in the spin-ice Dy2Ti2O7. This is achieved by applying a symmetry-breaking magnetic field with which we can manipulate density and orientation of the strings. In turn, heat capacity is described by a gas of magnetic monopoles interacting via a magnetic Coulomb interaction.
description: 32 pages (19 pages of article, 13 pages of supporting online material)
A PROPOSED MODEL FOR ESTABLISHING A DIGITAL RESEARCH PLATFORM IN THE LIGHT OF GLOBAL MODELS AND EXPERIENCES
Creators: name: Dr. AFRAH ALI SALIH AL-AMARI
name: Dr. ZAMZAM SALIH SAAD AL-KHAWLANI
Publisher: name: Zenodo
Year: 2023
Subjects: Model/ Research Platform/ Digital Platform/ Digital Research Platform/ Global Models and Experiences.

description: Abstract
The study aimed to build a proposed model for establishing a digital research platform in light of global models and experiences, by identifying the role of digital platforms in promoting scientific research, the most important global models and experiences in adopting digital research platforms, and arriving at the proposed model for creating a digital research platform in light of models and experiences. . . Global, and to achieve this, the study relied on the descriptive survey method by monitoring and reviewing previous literature and studies that dealt with digital platforms and promoting scientific research through them. The study came up with a proposed model for creating a digital research platform in light of global models and experiences.
Fabrication of a drug delivery system that enhances antifungal drug corneal penetration
Creators: name: Li, Jingguo
name: Li, Zhanrong
name: Liang, Zhen
name: Han, Lei
name: Feng, Huayang
name: He, Siyu
name: Zhang, Junjie
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Computational Biology

description: Fungal keratitis (FK) remains a severe eye disease, and effective therapies are limited by drug shortages and critical ocular barriers. Despite the high antifungal potency and broad spectrum of econazole, its strong irritant and insolubility in water hinder its ocular application. We designed and fabricated a new drug delivery system based on a polymeric vector for the ocular antifungal application of econazole. This novel system integrates the advantages of its constituent units and exhibits superior comprehensive performance. Using the new system, drug content was significantly increased more than 600 folds. The results of in vivo and in vitro experiments demonstrated that the econazole-loaded formulation exhibited significantly enhanced corneal penetration after a single topical ocular administration, excellent antifungal activity, and good tolerance in rabbits. Drug concentrations and ocular relative bioavailability in the cornea were 59- and 29-time greater than those in the control group, respectively. Following the topical administration of one eye drop (50 μL of 0.3% w/v econazole) in fungus-infected rabbits, a high concentration of antimycotic drugs in the cornea and aqueous humor was sustained and effective for 4 h. The mechanism of corneal penetration was also explored using dual fluorescent labeling. This novel drug delivery system is a promising therapeutic approach for oculomycosis and could serve as a candidate strategy for use with various hydrophobic drugs to overcome barriers in the treatment of many other ocular diseases.
Correlation of strain, wing tilt, dislocation density, and photoluminescence in epitaxial lateral overgrown GaN on SiC substrates
Creators: name: Gmeinwieser, Nikolaus
name: Engl, Karl
name: Gottfriedsen, P.
name: Schwarz, Ulrich
name: Zweck, Josef
name: Wegscheider, Werner
name: Miller, S.
name: Lugauer, H.-J.
name: Leber, A.
name: Weimar, A.
name: Lell, Alfred
name: Härle, Volker
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: gallium compounds, III-V semiconductors, semiconductor epitaxial layers, semiconductor growth, wide band gap semiconductors, dislocation density, photoluminescence, X-ray diffraction, scanning electron microscopy, masks, transmission electron microscopy, internal stresses
subject: 530 Physik
subject: 81.05.Ea; 68.47.Fg; 78.55.Cr; 61.72.Ff; 68.55.Jk; 78.66.Fd; 68.60.Bs;

description: Epitaxial lateral overgrown (ELOG) gallium nitride (GaN) on SiC is being studied as a possible substrate for blue laser diodes. A defect density below 2.2×107 cm–2 in the wings, compared to 2×109 cm–2 in the windows, was achieved. Interaction of the overgrown GaN with the SiO2 mask causes a few degree wing tilt and a transition region of high defect density between windows and wings. Diminished PL, strong tensile stress, and a defect correlated line at around 3.4 eV emerge in this up to two-micron-wide transition region. By changing the mask material from SiO2 to SiN we were able to reduce the wing tilt drastically to below 0.7°. This eliminates the defective transition region and extends the low strain and the low defect density area of the ELOG wings. The methods used to study strain, wing tilt, and threading dislocations in the ELOG samples are microphotoluminescence (µPL), transmission electron microscopy, x–ray diffraction, and scanning electron microscope. We also demonstrate the use of the first momentum of the µPL spectra as an effective means to measure strain distribution.
Construction of symplectic structures on 4-manifolds with a free circle action
Creators: name: Friedl, Stefan
name: Vidussi, Stefano
Publisher: name: arXiv
Year: 2011
Subjects: subject: Geometric Topology (math.GT)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D05

description: Let $M$ be a closed 4-manifold with a free circle action. If the orbit manifold $N^3$ satisfies an appropriate fibering condition, then we show how to represent a cone in $H^2(M;\R)$ by symplectic forms. This generalizes earlier constructions by Thurston, Bouyakoub and Fernández-Gray-Morgan. In the case that $M$ is the product 4-manifold $S^1\times N$ our construction complements the results of \cite{FV08} (arXiv:0805:1234 [math.GT]) and allows us to completely determine the symplectic cone of such 4-manifolds. The content of this paper partly overlaps with the content of the unpublished preprint "Symplectic 4-manifolds with a free circle action" (arXiv:0801.1313 [math.GT]).
description: 11 pages
CMOS circuits for RF energy harvesting applications
Creators: name: Dehghani, Soroush
Publisher: name: University of British Columbia
Year: 2018

description: The explosive growth in Wireless Sensor Networks, ranging from the Internet of Things to embedded sensors for smart infrastructures and biomedical implants, continues to motivate the design and development of low-power energy harvesting systems that can either remotely charge a battery in the sensor unit or completely self-power the sensor from harvested energy. This thesis focuses on designing new benchmarks for monolithic RF rectifiers implemented in CMOS technology. A design procedure based on the theory of time-reversal duality is applied to transform power amplifier circuits into self-synchronous rectifier circuits. The methodology is distinctly different from other CMOS RF rectifier designs which use voltage-multiplier techniques. An advantage of transforming amplifier into rectifier circuits is that output matching in the amplifier is transformed to input matching in the rectifier. All the rectifier circuits described in this work include single-ended RF input ports matched to 50 Ω. Also, the circuits are self-biased and completely powered from the RF signal. Terminating rectifiers with an optimum load is important to maximize the RF to dc power conversion efficiency. The optimum load resistance can vary as a function of input power. Therefore, an adjustable load that tracks changes in RF power is proposed to maximize efficiency. As a way of implementing an adjustable load circuit, a discontinuous mode dc to dc converter that is controlled by an input loop to regulate the load impedance of the rectifier is presented. The analysis, design and experimental results of the adjustable load circuit are described and the performance is verified with 10 W GaN Class-F RF rectifier. In the final part of this thesis, a bidirectional and reconfigurable class-DE circuit is proposed to support the implementation of embedded sensor nodes that are self-powered and using a time-division duplexing architecture. The circuit reconfigures the same RF front-end circuit into either a high-efficiency rectifier or a highly efficient power oscillator that can be modulated to transmit sensor data. The two modes can be time multiplexed to switch between RF energy harvesting and transmission. The design was implemented in 65 nm CMOS technology and experimental results for both modes of operation are presented.
Generalized pricing formulas for stochastic volatility jump diffusion models applied to the exponential Vasicek model
Creators: name: Liang, L. Z. J.
name: Lemmens, D.
name: Tempere, J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Pricing of Securities (q-fin.PR)
subject: Computational Finance (q-fin.CP)
subject: FOS: Economics and business

description: Path integral techniques for the pricing of financial options are mostly based on models that can be recast in terms of a Fokker-Planck differential equation and that, consequently, neglect jumps and only describe drift and diffusion. We present a method to adapt formulas for both the path-integral propagators and the option prices themselves, so that jump processes are taken into account in conjunction with the usual drift and diffusion terms. In particular, we focus on stochastic volatility models, such as the exponential Vasicek model, and extend the pricing formulas and propagator of this model to incorporate jump diffusion with a given jump size distribution. This model is of importance to include non-Gaussian fluctuations beyond the Black-Scholes model, and moreover yields a lognormal distribution of the volatilities, in agreement with results from superstatistical analysis. The results obtained in the present formalism are checked with Monte Carlo simulations.
description: 9 pages, 2 figures, 1 table
Gravitational Atom in Compactified Extra Dimensions
Creators: name: Floratos, E. G.
name: Leontaris, G. K.
name: Vlachos, N. D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider quantum mechanical effects of the modified Newtonian potential in the presence of extra compactified dimensions. We develop a method to solve the resulting Schroedinger equation and determine the energy shifts caused by the Yukawa-type corrections of the potential. We comment on the possibility of detecting the modified gravitational bound state Energy spectrum by present day and future experiments.
description: 12 pages, 2 figures
Group-theoretical approach to a non-central extension of the Kepler-Coulomb problem
Creators: name: Kerimov, Gul-Mirza
name: Ventura, Alberto
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Bound and scattering states of a non-central extension of the three-dimensional Kepler-Coulomb Hamiltonian are worked out analytically within the framework of the potential groups of the problem, SO(7) for bound states and SO(6,1) for scattering states. In the latter case, the S matrix is calculated by the method of intertwining operators.
description: 12 pages, to appear in J. Phys. A : Math. Theor
Spin Correlations in the Geometrically Frustrated RBaCo4O7 Antiferromagnets: Mean-Field Approach and Monte-Carlo Simulations
Creators: name: Khalyavin, D. D.
name: Manuel, P.
name: Mitchell, J. F.
name: Chapon, L. C.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Spin correlations in the geometrically frustrated RBaCo4O7 compounds, usually described as an alternating stacking of Kagome and triangular layers on a hexagonal lattice, have been studied by mean-field approach and by Monte-Carlo simulations. The behavior of the system was modelled with an isotropic Heisenberg Hamiltonian as a function of the relevant parameter Jout/Jin, representing the ratio between exchange integrals inside the Kagome layers, Jin, and between Kagome and triangular layers, Jout. This ratio can be varied in real systems by appropriate chemical substitutions. At the mean-field level, long-range magnetic order with the wave vector at the K-point of symmetry (k=a*/3+b*/3) has been found for Jout/Jin>0.7. Below this value, the dominant Fourier modes are completely degenerate in the entire Brillouin zone. The Monte-Carlo simulations revealed that the long-range ordered configuration found in the mean-field calculations becomes the ground state of the system for Jout/Jin>1.5. Below this critical ratio, quasi one-dimensional magnetic ordering along the c-axis, involving spins of the triangular sublattice was observed. The correlations in the (ab) plane were found to have a short-range 120o character with correlation length dependent on Jout/Jin.
title: Ergebnisse des Leopoldina-Förderprogramms VI
Creators: name: :None
Publisher: name: Wissenschaftliche Verlagsgesellschaft Stuttgart
Year: 2008
Subjects: subject: Förderungsprogramm
subject: Stipendium
subject: Wissenschaftlicher Nachwuchs
subject: 000

description: Deutschlands älteste Akademie, die Deutsche Akademie der Naturforscher Leopoldina, bemüht sich in besonderem Maße um die Förderung von Nachwuchswissenschaftlern. Seit 1992 vergibt sie zur Unterstützung der beruflichen Weiterentwicklung herausragender junger Wissenschaftlerinnen und Wissenschaftler ein Stipendium, ausgestattet durch Zuwendungen des Bundesministeriums für Bildung und Forschung, das es den Ausgezeichneten ermöglicht, innerhalb von zwei bis drei Jahren eigenständig ein außergewöhnlich innovatives Forschungsprojekt an ausländischen Wissenschaftseinrichtungen umzusetzen. Über 320 Forscherinnen und Forscher konnten seit Beginn des Programms gefördert werden. Der vorliegende Band zeigt die Vielfalt der Projekte und liefert Beispiele für die erreichten Ergebnisse seit 2006. Damit werden Chancen und Ansprüche des Förderprogramms für künftige Bewerber deutlich.
description: Nova Acta Leopoldina - Supplementum: Abhandlungen der Deutschen Akademie der Naturforscher (Leopoldina), vol. 21
Non-conservative forces and effective temperatures in active polymers
Creators: name: Loi, Davide
name: Mossa, Stefano
name: Cugliandolo, Leticia F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Cell Behavior (q-bio.CB)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: We follow the dynamics of an ensemble of interacting self-propelled semi-flexible polymers in contact with a thermal bath. We characterize structure and dynamics of the passive system and as a function of the motor activity. We find that the fluctuation-dissipation relation allows for the definition of an effective temperature that is compatible with the results obtained by using a tracer particle as a thermometer. The effective temperature takes a higher value than the temperature of the bath when the effect of the motors is not correlated with the structural rearrangements they induce. Our data are compatible with a dependence upon the square of the motor strength (normalized by the average internal force) and they suggest an intriguing linear dependence on the tracer diffusion constant times the density of the embedding matrix. We show how to use this concept to rationalize experimental results and suggest possible innovative research directions.
Folate-targeting annonaceous acetogenins nanosuspensions: significantly enhanced antitumor efficacy in HeLa tumor-bearing mice
Creators: name: Li, Haowen
name: Li, Yijing
name: Ao, Hui
name: Bi, Dongdong
name: Han, Meihua
name: Guo, Yifei
name: Wang, Xiangtao
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Cell Biology
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: Annonaceous acetogenins (ACGs) are one of the most active constituents isolated from Annona species with potent antitumor activity. However, the poor solubility and severe side effect greatly limit their use in clinic. In this study, folic acid (FA) modified annonaceous acetogenins nanosuspensions (FA-PEG-ACGs-NSps) had been successfully prepared using DSPE-PEG-FA and soybean lecithin (SPC) as stabilizers. The resultant FA-PEG-ACGs-NSps had a mean particle size of 119.7 nm, a zeta potential of –23.0 mV and a high drug payload of 49.68%. The obtained ACGs-NSps had a good stability in various physiological media, and showed sustained drug release. Compared to common ACGs nanoparticles (PEG-ACGs-NSps), FA-PEG-ACGs-NSps showed significantly enhanced in vitro cytotoxicity against folate receptor-positive HeLa cell lines (IC50, 0.483 μg/mL vs. 0.915 μg/mL, p In vivo experiments demonstrated that FA-PEG-ACGs-NSps brought more drug molecules into tumors and greatly improved the antitumor efficacy (TIR, 76.45% vs. 25.29%, p
Topological phases, Majorana modes and quench dynamics in a spin ladder system
Creators: name: DeGottardi, Wade
name: Sen, Diptiman
name: Vishveshwara, Smitha
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We explore the salient features of the `Kitaev ladder', a two-legged ladder version of the spin-1/2 Kitaev model on a honeycomb lattice, by mapping it to a one-dimensional fermionic p-wave superconducting system. We examine the connections between spin phases and topologically non-trivial phases of non-interacting fermionic systems, demonstrating the equivalence between the spontaneous breaking of global Z2 symmetry in spin systems and the existence of isolated Majorana modes. In the Kitaev ladder, we investigate topological properties of the system in different sectors characterized by the presence or absence of a vortex in each plaquette of the ladder. We show that vortex patterns can yield a rich parameter space for tuning into topologically non-trivial phases. We introduce a new topological invariant which explicitly determines the presence of zero energy Majorana modes at the boundaries of such phases. Finally, we discuss dynamic quenching between topologically non-trivial phases in the Kitaev ladder, and in particular, the post-quench dynamics governed by tuning through a quantum critical point.
description: 15 pages, 4 figures
Water-soluble substituted chitosan derivatives as technology platform for inhalation delivery of siRNA
Creators: name: Capel, Victoria
name: Vllasaliu, Driton
name: Watts, Peter
name: Clarke, Philip A.
name: Luxton, Dominic
name: Grabowska, Anna M.
name: Mantovani, Giuseppe
name: Stolnik, Snjezana
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Cancer

description: Despite research efforts full potential of siRNA-based therapeutics has not yet been fully realized due to a need for suitable, effective delivery formulations. Here, we examine a potential of a new class of water-soluble chitosans as siRNA platform for pulmonary delivery. The system is based on piperazine-substituted chitosans, a material designed to integrate established, safe application of chitosan for mucosal administration with novel properties: the piperazine-substituted chitosans are freely water-soluble at physiological pH, possess low cytotoxicity (no significant reduction in cell viability up to 0.1 mg/ml), and provide efficient incorporation of siRNA into sub-300 nm colloidal complexes (at relatively low polymer/siRNA ratio of 5:1). In vitro, the complexes achieved silencing of a model gene at a level of 40–80%, when tested in a panel of lung epithelial cells. Considering the formulation ‘developability’, there were no significant changes in the complexes’ size and integrity on aerosolisation by microsprayer (PenCentury™) device. Following intratracheal aerolisation, the complexes deposited throughout the lung, although relatively inhomogeneously, as judged from IVIS imaging of the isolated mouse lung (visualizing DY647-siRNA). In vivo data illustrate absence of adverse effects on repeated administration of complexes and significant tumor reduction in atopical lung cancer model in mice. Altogether, the data illustrates potential of substituted chitosan derivatives to be utilized as a safe system for inhalation delivery of siRNA.
On non-linear CMB temperature anisotropy from gravitational perturbations
Creators: name: Gao, Xian
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Non-linear CMB temperature anisotropies up to the third-order on large scales are calculated. On large scales and in the Sachs-Wolfe limit, we give the explicit expression for the observed temperature anisotropy in terms of the primordial curvature perturbation up to the third-order. We derived the final bispectrum and trispectrum of anisotropies and the corresponding non-linear parameters, in which the contributions to the observed non-Gaussianity from primordial perturbations and from the non-linear mapping from primordial curvature perturbation to the temperature anisotropy are transparently separated.
description: 11 pages, 2 figures
Quantum rings as phase coherent detectors
Creators: name: Fuhrer, A.
name: Sigrist, Martin
name: Meier, L.
name: Ihn, Thomas
name: Ensslin, Klaus
name: Wegscheider, Werner
name: Bichler, Max
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: Transmission phase; Quantum dot; Aharonov–Bohm effect; Phase coherence
subject: 530 Physik
subject: 73.23.Ad; 73.63.Kv

description: Aharonov–Bohm oscillations are studied in the magnetoconductance through two micron-sized quantum rings. The structures are defined in a two-dimensional electron gas of a Ga[Al]As heterostructure by way of local oxidation with an atomic force microscope. In the experiments, the rings are used as phase-coherent detectors of the charge state of quantum dots coupled to the rings in two specific arrangements. In the first case, two quantum dots are induced in each of the arms of an open four-terminal ring geometry. This allows to measure the evolution of the relative transmission phase when the number of electrons in each of the dots is tuned using appropriate gate voltages. The experimental findings are compared to expectations from single-particle theory and deviations are discussed. In the second case, a quantum dot is coupled capacitively to one arm of a ring. The amplitude of the Aharonov–Bohm oscillations in the transconductance depends strongly on the charge state of the quantum dot. It is demonstrated that the effect is due to a single-electron screening effect. This shows that Aharonov–Bohm oscillations in a quantum ring can be used for the detection of single electronic charges.
A Weyl-Dirac Cosmological Model with DM and DE
Creators: name: Israelit, Mark
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In the Weyl-Dirac (W-D) framework a spatially closed cosmological model is considered. It is assumed that the space-time of the universe has a chaotic Weylian microstructure but is described on a large scale by Riemannian geometry. Locally fields of the Weyl connection vector act as creators of massive bosons having spin 1. It is suggested that these bosons, called weylons, provide most of the dark matter in the universe. At the beginning the universe is a spherically symmetric geometric entity without matter. Primary matter is created by Dirac's gauge function very close to the beginning. In the early epoch, when the temperature of the universe achieves its maximum, chaotically oriented Weyl vector fields being localized in micro-cells create weylons. In the dust dominated period Dirac's gauge function is giving rise to dark energy, the latter causing the cosmic acceleration at present. This oscillatory universe has an initial radius identical to the Plank length = 1.616 exp (-33) cm, at present the cosmic scale factor is 3.21 exp (28) cm, while its maximum value is 8.54 exp (28) cm. All forms of matter are created by geometrically based functions of the W-D theory.
description: 25 pages. Submitted to GRG
Hyaluronic acid/doxorubicin nanoassembly-releasing microspheres for the transarterial chemoembolization of a liver tumor
Creators: name: Lee, Song Yi
name: Choi, Jin Woo
name: Lee, Jae-Young
name: Kim, Dae-Duk
name: Kim, Hyo-Cheol
name: Cho, Hyun-Jong
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Neuroscience
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Cancer

description: Doxorubicin (DOX)-loaded, hyaluronic acid-ceramide (HACE) nanoassembly-releasing poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) were developed for transarterial chemoembolization (TACE) therapy of liver cancer. DOX/HACE MSs with a mean diameter of 27 μm and a spherical shape were prepared based on the modified emulsification method. Their in vitro biodegradability in artificial biological fluids was observed. A more sustained drug release pattern was observed from DOX/HACE MS than from DOX MS at pH 7.4. The cellular internalization efficiency of DOX of the DOX/HACE MS group was higher than that of the DOX MS group in liver cancer cells (HepG2 and McA-RH7777 cells), mainly due to CD44 receptor-mediated endocytosis of the released DOX/HACE nanoassembly. In both HepG2 and McA-RH7777 cells, the antiproliferation and apoptotic potentials of the DOX/HACE MS were significantly higher than those of the DOX MS (p