| 1. |
- Jørgenrud, Benedicte, et al.
(författare)
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The Metabolome in Finnish Carriers of the MYBPC3-Q1061X Mutation for Hypertrophic Cardiomyopathy
- 2015
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Ingår i: PLOS ONE. - : PLOS One. - 1932-6203. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Mutations in the cardiac myosin-binding protein C gene (MYBPC3) are the most common genetic cause of hypertrophic cardiomyopathy (HCM) worldwide. The molecular mechanisms leading to HCM are poorly understood. We investigated the metabolic profiles of mutation carriers with the HCM-causing MYBPC3-Q1061X mutation with and without left ventricular hypertrophy (LVH) and non-affected relatives, and the association of the metabolome to the echocardiographic parameters.METHODS AND RESULTS: 34 hypertrophic subjects carrying the MYBPC3-Q1061X mutation, 19 non-hypertrophic mutation carriers and 20 relatives with neither mutation nor hypertrophy were examined using comprehensive echocardiography. Plasma was analyzed for molecular lipids and polar metabolites using two metabolomics platforms. Concentrations of branched chain amino acids, triglycerides and ether phospholipids were increased in mutation carriers with hypertrophy as compared to controls and non-hypertrophic mutation carriers, and correlated with echocardiographic LVH and signs of diastolic and systolic dysfunction in subjects with the MYBPC3-Q1061X mutation.CONCLUSIONS: Our study implicates the potential role of branched chain amino acids, triglycerides and ether phospholipids in HCM, as well as suggests an association of these metabolites with remodeling and dysfunction of the left ventricle.
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| 2. |
- Andersson, Roger, 1969-, et al.
(författare)
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Multimodal expressions of disciplinary relevant aspects in inquiry-based physics learning
- 2024
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Ingår i: Journal of Physics: Conference Series. - : Institute of Physics.
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Konferensbidrag (refereegranskat)abstract
- In this study we are interested in how learners of geometrical optics express disciplinary relevant aspects multimodally in an inquiry-based learning with support of a computer simulation. Students' discussions and work with the simulation were filmed, transcribed, and we analysed some parts of the transcript where the students show signs of disciplinary relevant aspects by a method based in conversation analysis. We found evidence that the students use multiple semiotic resources for expressing disciplinary relevant aspects about the tasks, especially gestures. The letter are by their visual nature well suited for communication in physics, and are used by the students to transduct semiotic information.
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| 3. |
- Bernad, Joszef Zsolt, et al.
(författare)
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Effects of a quantum measurement on the electric conductivity : Application to graphene
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:7
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Tidskriftsartikel (refereegranskat)abstract
- We generalize the standard linear-response (Kubo) theory to obtain the conductivity of a system that is subject to a quantum measurement of the current. Our approach can be used to specifically elucidate how back-action inherent to quantum measurements affects electronic transport. To illustrate the utility of our general formalism, we calculate the frequency-dependent conductivity of graphene and discuss the effect of measurement-induced decoherence on its value in the dc limit. We are able to resolve an ambiguity related to the parametric dependence of the minimal conductivity.
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| 4. |
- Dutta, Omjyoti, et al.
(författare)
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Polarizing beam splitter for dipolar molecules
- 2005
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 71:5
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Tidskriftsartikel (refereegranskat)abstract
- We propose a coherent beam splitter for polarized heteronuclear molecules based on a stimulated Raman adiabatic passage scheme that uses a tripod linkage of electrotranslational molecular states. We show that for strongly polarized molecules the rotational dynamics imposes significantly larger Rabi frequencies than would otherwise be expected, but within this limitation, a full transfer of the molecules to two counterpropagating ground-state wave packets is possible.
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| 5. |
- Dutta, Omjyoti, et al.
(författare)
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Single-mode acceleration of matter waves in circular waveguides
- 2006
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 74:2
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Tidskriftsartikel (refereegranskat)abstract
- Ultracold gases in ring geometries hold promise for significant improvements of gyroscopic sensitivity. Recent experiments have realized atomic and molecular storage rings with radii in the centimeter range, sizes whose practical use in inertial sensors requires velocities significantly in excess of typical recoil velocities. We use a combination of analytical and numerical techniques to study the coherent acceleration of matter waves in circular waveguides, with particular emphasis on its impact on single-mode propagation. In the simplest case we find that single-mode propagation is best maintained by the application of time-dependent acceleration force with the temporal profile of a Blackmann pulse. We also assess the impact of classical noise on the acceleration process.
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| 6. |
- Dutta, Omjyoti, et al.
(författare)
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Thomas-Fermi ground state of dipolar fermions in a circular storage ring
- 2006
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 73:4
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments in the field of ultracold gases has led to the production of degenerate samples of polar molecules. These have large static electric-dipole moments, which in turn causes the molecules to interact strongly. We investigate the interaction of polar particles in waveguide geometries subject to an applied polarizing field. For circular waveguides, tilting the direction of the polarizing field creates a periodic inhomogeneity of the interparticle interaction. We explore the consequences of geometry and interaction for stability of the ground state within the Thomas-Fermi model. Certain combinations of tilt angles and interaction strengths are found to preclude the existence of a stable Thomas-Fermi ground state. The system is shown to exhibit different behavior for quasi-one-dimensional and three-dimensional trapping geometries.
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| 7. |
- Jääskeläinen, Markku, 1970-
(författare)
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Adiabatic guiding of matter waves
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent efforts in the field of ultracold atoms have goneinto creating wave guides of sub-micron sizes. In this thesis,the quantum dynamics of matter waves in such confiningpotential structures with minima extended in space isinvestigated. A general framework based upon the separation ofthe wave function for the quantum particle using a discrete setof mode functions is introduced to reduce the dimensionality ofthe problem. Conditions for propagation in the form ofindependent modes, i.e. adiabatic propagation, are determinedfor the case of matter waves with spatially varying width andfound to be connected to the diffraction of matter wavesthrough a dimensionless parameter, the Fresnel parameter.Further, the analysis is extended to include situationswhere a transition to completely non-adiabatic dynamics takesplace. Here it is found that focusing of matter waves due toenergy redistribution at the end of adiabatic guiding isdetermined by the Fresnel parameter found earlier. In theadiabatic regime, the essential dynamics in the directiontransverse to the minimal valley of the guiding potentialstructure occurs at a time-scale much shorter than that ofchanges in the propagating direction. As a result of this,reection of matter waves is likely to occur unless the changesare made over very long distances.The formalism of adiabatic propagation is also applied thesituation of splitting of matter waves in potential structures.It is found that the adiabaticity criteria are identical tothose for a single guide of spatially varying width. Aformulation of adiabatic splitting in terms of states localizedclose to either of the two minima is developed. The inuence oflongitudinal localization on the splitting of coherentsuperposition states is examined and found to be described by asimple analytical expression.
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| 8. |
- Jääskeläinen, Markku, 1970-, et al.
(författare)
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Adiabatic propagation in potential structures
- 2002
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 66:2
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Tidskriftsartikel (refereegranskat)abstract
- In this work the adiabatic approximation is applied to the propagation of matter waves in confined geometries like those experimentally realized in recent atom optical experiments. Adiabatic propagation along a channel is assumed not to mix the various transverse modes. Nonadiabatic corrections arise from the potential squeezing and bending. Here we investigate the effect of the former. Detailed calculations of two-dimensional propagation are carried out both exactly and in an adiabatic approximation. This offers the possibility to analyze the validity of adiabaticity criteria. A semiclassical (sc) approach, based on the sc Massey parameter is shown to be inadequate, and the diffraction due to wave effects must be included separately. This brings in the Fresnel parameter well known from optical systems. Using these two parameters, we have an adequate understanding of adiabaticity on the system analyzed. Thus quantum adiabaticity must also take cognizance of the intrinsic diffraction of matter waves.
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| 9. |
- Jääskeläinen, Markku, 1970-, et al.
(författare)
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Anomalous spin-related quantum phase in mesoscopic hole rings
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:15
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Tidskriftsartikel (refereegranskat)abstract
- We have obtained numerically exact results for the spin-related geometric quantum phases that arise in p-type semiconductor ring structures. The interplay between gate-controllable (Rashba) spin splitting and quantum-confinement-induced mixing between hole-spin states causes a much higher sensitivity of magnetoconductance oscillations to external parameters than previously expected. Our results imply a much-enhanced functionality of hole-ring spin-interference devices and shed new light on recent experimental findings.
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| 10. |
- Jääskeläinen, Markku, 1970-, et al.
(författare)
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Bifurcations and bistability in cavity-assisted photoassociation of Bose-Einstein-condensed molecules
- 2007
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 76:6
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Tidskriftsartikel (refereegranskat)abstract
- We study the photoassociation of Bose-Einstein condensed atoms into molecules using an optical cavity field. The driven cavity field introduces a dynamical degree of freedom into the photoassociation process, whose role in determining the stationary behavior has not previously been considered. The semiclassical stationary solutions for the atom and molecules as well as the intracavity field are found and their stability and scaling properties are determined in terms of experimentally controllable parameters including driving amplitude of the cavity and the nonlinear interactions between atoms and molecules. For weak cavity driving, we find a bifurcation in the atom and molecule number occurs that signals a transition from a stable steady state to nonlinear Rabi oscillations. For a strongly driven cavity, there exists bistability in the atom and molecule number.
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