Science.gov (United States)

Gestational Diabetes; Hyperlipidemia

Science.gov (United States)

Omega-3 Fatty Acids; Lipid Peroxidation

UK PubMed Central (United Kingdom)

The lipid composition of skin is important to a variety of functions served by this organ. Therefore, skin expresses multiple enzymes that synthesize and metabolize lipids. An important class of lipid...Full Text Available

Science.gov (United States)

Apr 21, 2011 ... The system of lipid peroxidation reacts regularly to adverse effects and results in enhancement of lipid peroxidation and build-up of LPO ...

Energy Technology Data Exchange (ETDEWEB)

Short communication.

UK PubMed Central (United Kingdom)

BackgroundSteroidogenic acute regulatory (StAR) protein related lipid transfer (START) domains are small globular modules that form a cavity where lipids and lipid hormones bind....Full Text Available

CERN Document Server

Quantum man

UK PubMed Central (United Kingdom)

Mitochondria must uptake some phospholipids from the endoplasmic reticulum (ER) for the biogenesis of their membranes. They convert one of these lipids, phosphatidylserine, to phosphatidylethanolamine,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundAdipose tissue lipid storage and processing capacity can be a key factor for obesity-related metabolic disorders such as insulin resistance and diabetes. Lipid uptake is...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The concentrations of iron, chromium, zinc, and aluminum were measured by atomic absorption spectroscopy in the lipid-soluble fractions of tar from the process stream of an experimental coal gasifier as part of large study on the health risks of coal gasification. Lipid solubility was inferred from octanol/water-partitioning and benzene-solubility tests. The properties of the lipid-soluble metals were compared to reference compounds by Sephadex LH-20 chromatography. The ability of the lipid-soluble metals to remain lipid soluble after treatment with acid and base was also tested. Lipid-soluble iron, chromium, zinc, and aluminum were present at 360, 12, 3, and 1 ppM, respectively, in the gasifier coal tar. The presence of these metals in lipid-soluble form may have important consequences relative to the potential toxicity of the tar if ...

DEFF Research Database (Denmark)

Lipids in the stratum corneum (SC) are of major importance for the skin barrier function. Many different methods have been used for the collection of SC for the analysis of SC lipids. The objective of the present study was to validate the cyanoacrylate method for the collection of SC in relation to lipid analysis.

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

Dyslipidemia

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

... decoherence. Descriptors : *QUANTUM COMPUTING, NUCLEAR MAGNETIC RESONANCE, JOSEPHSON JUNCTIONS. Subject ...

UK PubMed Central (United Kingdom)

Purpose.The cornea is protected by apical hydrophilic transmembrane mucins and tears. In pathologic states the mucin barrier is disrupted, creating potential for meibomian lipids...Full Text Available

UK PubMed Central (United Kingdom)

Integration of solid-state biosensors and lipid bilayer membranes is important for membrane protein research and drug discovery. In these sensors, it is critical that the solid-state sensing...Full Text Available

UK PubMed Central (United Kingdom)

AMP-activated-protein-kinase (AMPK) is a key sensor and regulator of cellular and whole-body energy metabolism and plays a key role in regulation of lipid metabolism. Since lipid metabolism...Full Text Available

UK PubMed Central (United Kingdom)

The binding of amphiphilic molecules to lipid bilayers is followed by ¹⁹F NMR using chemical shift and line shape differences between the solution and membrane-tethered states of...Full Text Available

UK PubMed Central (United Kingdom)

The authors' laboratory, using histochemicalmethods, previously identified two types of cholesterol-containing lipid particles in the extracellular spaces of human atherosclerotic lesions, one particle...Full Text Available

International Nuclear Information System (INIS)

... chemical radiation effects decomposition extraction columns gamma radiation

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

CERN Document Server

We discuss models of computing that are beyond classical. The primary motivation is to unearth the cause of nonclassical advantages in computation. Completeness results from computational complexity theory lead to the identification of very disparate problems, and offer a kaleidoscopic view into the realm of quantum enhancements in computation. Emphasis is placed on the `power of one qubit' model, and the boundary between quantum and classical correlations as delineated by quantum discord. A recent result by Eastin on the role of this boundary in the efficient classical simulation of quantum computation is discussed. Perceived drawbacks in the interpretation of quantum discord as a relevant certificate of quantum enhancements are addressed.

Energy Technology Data Exchange (ETDEWEB)

Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme.

Energy Technology Data Exchange (ETDEWEB)

A preliminary chemical characterization is presented of phosphate-free aminolipids isolation from Chlorobium limicola f. thiosulfatophilum. The lipid contains no phosphorus, glycerol, sugar, ornithine, or lysine. Ultraviolet absorption and fluorescence spectra indicate that the amino moiety of the lipid is an aromatic heterocyclic compound. Infrared spectra indicate that the lipid is a secondary or tertiary amide, and gas chromatograhic analysis of the hydrolyzed lipid shows that for each 1100 g of lipid, 1 mol of myristic acid (C/sub 14:0/) is linked in an amide bond. Acid hydrolysis of the lipid yields two fluorescent substances, A (ninhydrine positive) and B (negative), in addition to myristic acid. Proton nuclear magnetic resonance (NMR) studies indicate that substance A contains a butyl groups attached to a conjugated ring carbon, two equivalent ethyl ...

International Nuclear Information System (INIS)

Apart from conventional phase transitions driven by the thermal effects, quantum phase transitions generated by quantum fluctuations have their own mechanisms that are reflected in critical phenomena. Quantum phase transitions have an origin from spontaneous symmetry breaking commonly to thermal phase transitions. Even in this case, inherent quantum fluctuations substantially modify and yield new aspects. Quantum phase transitions have, however, another mechanism caused by topology changes, which gives completely new characters. Recently, a mechanism which connects these two has been found. Proimities from first-order transitions and phase separatins as well as from multiphase coexistence also generate characteristic and unconventional quantum criticalities. Understanding novel quantum criticalities offers a firm basis of recent active ...

Energy Technology Data Exchange (ETDEWEB)

Over the past two decades, quantum computing has become a popular and promising approach to trying to solve computationally difficult problems. Missing in many descriptions of quantum computing is just how probability enters into the process. Here, we discuss some simple examples of how uncertainty and probability enter, and how this and the ideas of quantum computing challenge our interpretations of quantum mechanics. It is found that this uncertainty can lead to intrinsic decoherence, and this raises challenges for error correction. (viewpoint)

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

UK PubMed Central (United Kingdom)

The biophysical properties of membrane phospholipids are controlled by the composition of their constituent fatty acids and are tightly regulated in Escherichia...Full Text Available

UK PubMed Central (United Kingdom)

Evidence for the presence of undecaprenol in the unsaponifiable lipid of Lactobacillus plantarum (N.C.I.B. 6376) is presented. Characterization of the compound was based mainly on...Full Text Available

UK PubMed Central (United Kingdom)

The polyene antibiotic Amphotericin B (AMB) is one of the first therapeutic agents to be marketed commercially as nanosized formulations in which the drug is associated with lipids as liposomes or complexes....Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Quantum computers hold great promises for the future of computation. In this paper, this new kind of computing device is presented, together with a short survey of the status of research in this field. The principal algorithms are introduced, with an emphasis on the applications of quantum computing to physics. Experimental implementations are also briefly discussed.

Science.gov (United States)

During the entire performance period, from 12 May 2003 through 31 December 2006, we have conducted theoretical and computational research on quantum control problems central to quantum computation. In particular we completed a thorough and rigorous analys...

International Nuclear Information System (INIS)

Werner states are paradigmatic examples of quantum states and play an innovative role in quantum information theory. In investigating the correlating capability of Werner states, we find the curious phenomenon that quantum correlations, as quantified by the entanglement of formation, may exceed the total correlations, as measured by the quantum mutual information. Consequently, though the entanglement of formation is so widely used in quantifying entanglement, it cannot be interpreted as a consistent measure of quantum correlations per se if we accept the folklore that total correlations are measured (or rather upper bounded) by the quantum mutual information.

CERN Document Server

Theory of quantum games is relatively new to the literature and its applications to various areas of research are being explored. It is a novel interpretation of strategies and decisions in quantum domain. In the earlier work on quantum games considerable attention was given to the resolution of dilemmas present in corresponding classical games. Two separate quantum schemes were presented by Eisert et al. and Marinatto and Weber to resolve dilemmas in Prisoners' Dilemma and Battle of Sexes games respectively. However for the latter scheme it was argued that dilemma was not resolved. We have modified the quantization scheme of Marinatto and Weber to resolve the dilemma. We have developed a generalized quantization scheme for two person non-zero sum games which reduces to the existing schemes under certain conditions. Applications of this generalized quantization scheme to quantum ...

Energy Technology Data Exchange (ETDEWEB)

We survey results in lattice quantum chromodynamics from groups in the USQCD Collaboration. The main focus is on physics, but many aspects of the discussion are aimed at an audience of computational physicists.

Energy Technology Data Exchange (ETDEWEB)

At the occasion of the OECS conference in Madrid, we give a succinct account of some recent predictions in the spectroscopy of a quantum dot in a microcavity that remain to be observed experimentally, sometimes within the reach of the current state of the art.

Science.gov (United States)

Improved quantum-cascade lasers. (QCLs) are being developed as electri- ... These devices would supplant gas lasers as far-infrared sources. ...

CERN Document Server

A novel algebraic topology approach to supersymmetry (SUSY) and symmetry breaking in quantum field and quantum gravity theories is presented with a view to developing a wide range of physical applications. These include: controlled nuclear fusion and other nuclear reaction studies in quantum chromodynamics, nonlinear physics at high energy densities, dynamic Jahn-Teller effects, superfluidity, high temperature superconductors, multiple scattering by molecular systems, molecular or atomic paracrystal structures, nanomaterials, ferromagnetism in glassy materials, spin glasses, quantum phase transitions and supergravity. This approach requires a unified conceptual framework that utilizes extended symmetries and quantum groupoid, algebroid and functorial representations of non-Abelian higher dimensional structures pertinent to quantized spacetime topology and state space geometry of ...

International Nuclear Information System (INIS)

HIPDM is an "1"2"3I-labeled agent with a distribution in brain reflecting regional perfusion. This compound is neutral and lipid soluble at blood pH and freely crosses the blood-brain barrier. At the lower pH in brain, it picks up a hydrogen ion and becomes positively charged. In this form the molecule is not lipid soluble and it is trapped in brain.

CERN Document Server

We use X-ray scattering and molecular simulations to investigate the structural properties of complexes of multivalent cationic lipids and DNA molecules. At low mole fraction of neutral lipids (NLs), $\\Phi_{\\rm NL}$, the complexes show dramatic DNA compaction down to essentially close packed DNA arrays with a DNA interaxial spacing $d_{\\rm DNA}=25\\AA$. A gradual increase in $\\Phi_{\\rm NL}$ does not lead to a continuous increase in $d_{\\rm DNA}$ as observed for DNA complexes of monovalent cationic lipids (CLs). Instead, distinct spacing regimes exist, with sharp transitions between them. Three packing states have been identified: (i) close packed, (ii) condensed, but not close packed, with $d_{\\rm DNA}=27-28\\AA$, and (iii) an expanded state, where $d_{\\rm DNA}$ increases gradually with $\\Phi_{\\rm NL}$. Based on our experimental and computational results, we conclude that the DNA condensation is mediated by the ...

International Nuclear Information System (INIS)

This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar ...

CERN Document Server

We define the Bloch spectrum of a quantum graph to be the collection of the spectra of a family of Schr\\"odinger operators parametrized by the cohomology of the quantum graph. We show that the Bloch spectrum determines the Albanese torus, the block structure and the planarity of the graph. It determines a geometric dual of a planar graph. This enables us to show that the Bloch spectrum completely determines planar 3-connected quantum graphs.

International Nuclear Information System (INIS)

We discuss the use of active control to reduce mirror position fluctuations at the quantum level. We have shown in a recent experiment that it is possible to reduce the thermal noise of a mirror by measuring and controlling its motion with an optomechanical sensor based on a high-finesse optical cavity. This approach can be extended to lock the mirror motion at the quantum level, and to suppress the quantum effects of radiation pressure in interferometric measurements such as gravitational-wave detectors. The sensitivity improvement is furthermore independent of losses in the interferometer.

Science.gov (United States)

DC Field, Value, Language.

International Nuclear Information System (INIS)

... Abstract only 1063-7869 v. 44(10) CLASSICAL AND QUANTUM MECHANICS,

British Library Electronic Table of Contents (United Kingdom)

[image omitted

CERN Document Server

Here we show that self-propulsion in quantum vacuum may be achieved by rotating or aggregating magneto-electric nano-particles. The back-action follows from changes in momentum of electro-magnetic zero-point fluctuations, generated in magneto-electric materials. This effect may provide new tools for investigation of the quantum nature of our world. It might also serve in the future as a "quantum wheel" to correct satellite orientation in space.

Energy Technology Data Exchange (ETDEWEB)

A theoretical study of an exciton confined in a quantum ring is presented. The quantum ring is described as a two-dimensional circular quantum dot with a repulsive core, which is modelled with the help of two Gaussian functions. We have applied the variational method and investigated the evolution of the low-energy exciton spectrum with the change of the confinement potential. The calculations have been performed for the recently produced self-assembled ring-shaped InGaAs quantum dots. We have shown that the repulsive core strongly increases the radiative transition probability from the exciton ground state at the expense of the decreasing probability of the transitions from the excited states. This effect results from the orthogonality properties of the exciton wavefunctions, which are specific to the quantum-ring confinement potential. We have studied the characteristic features ...

Energy Technology Data Exchange (ETDEWEB)

A quantum computer would put the latest PC to shame. Not only would such a device be faster than a conventional computer, but by exploiting the quantum-mechanical principle of superposition it could change the way we think about information processing. However, two key goals need to be met before a quantum computer becomes reality. The first is to be able to control the state of a single quantum bit (or 'qubit') and the second is to build a two-qubit gate that can produce 'entanglement' between the qubit states. (U.K.)

Energy Technology Data Exchange (ETDEWEB)

This paper reports progress in the fabrication and characterization of an array of 1nm-scale colloidal particles (i.e., quantum-dot array) that can be operated to execute nontrivial and innovative computations, possibly including quantum logic. We discuss the actual fabrication of 2-nm metal clusters as an example of possible quantum dot implementation. Innovative and unconventional paradigms underlie the different stages of this work. For example, regular array geometry is achieved by directing appropriately derivatized metal clusters to preselected locations along a stretched strand of an engineered DNA sequence.

Energy Technology Data Exchange (ETDEWEB)

The diamond norm measures the distance between two quantum channels. From an operational viewpoint, this norm measures how well we can distinguish between two channels by applying them to the input states of arbitrarily large dimensions. In this paper, we show that the diamond norm can be conveniently, and in a physically transparent way, computed by means of a Monte Carlo algorithm based on the Fano representation of quantum states and quantum operations. The effectiveness of this algorithm is illustrated for several single-qubit quantum channels.

British Library Electronic Table of Contents (United Kingdom)

Ozone has in recent years been increasingly investigated for its potential use in the control of insect pests of stored cereals. Ozone is a powerful oxidizing agent that can react directly, or via production of reactive oxygen species, with proteins, DNA and double bonds of polyunsaturated fatty acids (PUFA). The aim of the present study was to investigate the mode of action in ozone toxicity using the red flour beetle, Tribolium castaneum (Herbst), as a relevant model. Transcription of focal genes thought to be involved in protection against ozone, and repair of cellular damage caused by ozone exposure, was studied together with the composition of storage lipid fatty acids and membrane phospholipid fatty acids in order to detect lipid peroxidation. Contrary to expectations, transcription ...

CERN Document Server

The Quantum Mechanics Conceptual Survey (QMCS) is a 12-question survey of students' conceptual understanding of quantum mechanics. It is intended to be used to measure the relative effectiveness of different instructional methods in modern physics courses. In this paper we describe the design and validation of the survey, a process that included observations of students, a review of previous literature and textbooks and syllabi, faculty and student interviews, and statistical analysis. We also discuss issues in the development of specific questions, which may be useful both for instructors who wish to use the QMCS in their classes and for researchers who wish to conduct further research of student understanding of quantum mechanics. The QMCS has been most thoroughly tested in, and is most appropriate for assessment of (as a posttest only), sophomore-level modern physics courses. We also describe testing with students in ...

CERN Document Server

A new mathematical framework is formulated to derive the effective equations of motion for the constrained quantum system which possesses an internal clock. In the realm close to classical behavior, the quantum evolution is approximated by a finite system of coupled but ordinary differential equations adhered to the weakly imposed Hamiltonian constraint. For the simplified version of loop quantum cosmology in the Bianchi I model with a free massless scalar filed, the resulting effective equations of motion affirm the bouncing scenario predicted by the previous studies: The big bang singularity is resolved and replaced by the big bounces, which take place up to three times, once in each diagonal direction, whenever the directional density approaches the critical value in the regime of Planckian density. It is also revealed that back-reaction arises from the quantum corrections and modifies the precise ...

CERN Document Server

The study of quantum walk process has been widely divided into the two standard variants, the discrete-time quantum walk (DTQW) and the continuous-time quantum walk (CTQW). The connection between the two variants has been established by considering limiting value of the coin operation parameter in the DTQW and the coin degree of freedom is show to be unnecessary [26]. But the coin degree of freedom is an additional resource which can be exploited to control the dynamics of the QW process. In this paper we present a generic quantum walk (QW) model using a quantum coin-embedded unitary shift operation U_{C}. The standard version of the DTQW and the CTQW can be conveniently retrieved from this generic model retaining the features of the coin degree of freedom in both the variants.

UK PubMed Central (United Kingdom)

A method for the study of conjugated polyelectrolyte (CPE) photophysics in solution at the single-molecule level is described. Extended observation times of single polymer molecules are enabled by the...Full Text Available

UK PubMed Central (United Kingdom)

Chronically elevated interleukin-6 (IL-6) affects lipid and lipoprotein metabolism. Individuals genetically predisposed to higher IL-6 secretion may be at risk of dyslipidemia, especially during the...Full Text Available

UK PubMed Central (United Kingdom)

Atg4 cysteine proteases (autophagins) play crucial roles in autophagy by proteolytic activation of Atg8 paralogs for targeting to autophagic vesicles by lipid conjugation, as well as in subsequent deconjugation...Full Text Available

Science.gov (United States)

Microbial/epithelial tissue. Szylit, O. Metabolic potential/microflora. Szylit, O. Lipid peroxidation. Popova, I.A. SLS-2. STS-58. 1993 ...

UK PubMed Central (United Kingdom)

BackgroundMicrovascular injury plays a key role in normal tissue radiation responses. Statins, in addition to their lipid-lowering effects, have vasculoprotective...Full Text Available

UK PubMed Central (United Kingdom)

Bacterial hydroxy fatty acids and alpha-hydroxy fatty acids have been demonstrated in complex lipid extracts of subgingival plaque and gingival tissue. However, little is known about the relationship...Full Text Available

UK PubMed Central (United Kingdom)

This neutron reflectometry study evaluates the structures resulting from different methods of preparing polymer-cushioned lipid bilayers. Four different techniques to deposit a dimyristoylphosphatidylcholine...Full Text Available

UK PubMed Central (United Kingdom)

Organisms in the genus Mycobacterium cause a variety of human diseases. One member of the genus, M. ulcerans, causes a necrotizing skin disease called Buruli ulcer....Full Text Available

UK PubMed Central (United Kingdom)

Natural abundance 13C solid-state nuclear magnetic resonance spectroscopy was used to investigate the effect of the incorporation of cholesterol on the dynamics of dimyristoylphosphatidylcholine (DMPC)...Full Text Available

UK PubMed Central (United Kingdom)

Many lifespan-modulating genes are involved in either generation of oxidative substrates and end-products, or their detoxification and removal. Among such metabolites, only lipoperoxides have the ability...Full Text Available

Science.gov (United States)

The goal of the present study is to elucidate the effect of lipid domain formation on activities of Naja naja atra and Bungarus multicinctus phospholipase A(2) (PLA(2)) enzymes. Sphingomyelin inhibited enzymatic activity and membrane-damaging activity of PLA(2) against egg yolk phosphatidylcholine (EYPC), while cholesterol and cholesterol sulfate abrogated the inhibitory effect of sphingomyelin. The ability of cholesterol and cholesterol sulfate to abolish the inhibitory effect of sphingomyelin was closely related to their capacity to induce domain formation in EYPC/sphingomyelin vesicles. Laurdan fluorescence measurement revealed that membrane packing of EYPC/sphingomyelin vesicles was differently affected by cholesterol and cholesterol sulfate. Unlike cholesterol, cholesterol sulfate was unable to promote domain formation in dipalmitoylphosphatidylcholine (DPPC) vesicles. Cholesterol increased but cholesterol sulfate reduced PLA(2) activity against DPPC. ...

UK PubMed Central (United Kingdom)

The beneficial effect of improving yeast redox response by increasing thioredoxin levels has been shown. Decreased lipid and protein oxidation is reflected in an increased biomass yield. In addition,...Full Text Available

International Nuclear Information System (INIS)

The aim of this study was to evaluate the radioprotective effect of turmeric extract (40 mg/kg body weight) and vitamin E (#alpha# - tocopherol acetate, 400 IU/kg body weight) supplementation on lipid peroxidation, reduced glutathione and antioxidant defense enzymes in various organs like liver, kidney and salivary glands at 24 h in adult Swiss mice. "1"3"1Iodine exposure significantly increased lipid peroxidation in kidney and salivary glands in comparison to control animals. Pre supplementation with turmeric extract for 15 days showed significant lowering of lipid peroxidation in kidney. On the other hand vitamin E pre supplementation showed marked reduction in lipid peroxidation in salivary glands. Reduced glutathione levels decreased significantly in liver after radiation exposure. However, pre supplementation with turmeric extract and vitamin E did not improve glutathione levels in liver. In ...

UK PubMed Central (United Kingdom)

BackgroundNeuropathic pain (NP) is partially mediated by neuroinflammatory mechanisms, and also modulates local neurogenic inflammation. Dietary lipids, in particular the total amount...Full Text Available

UK PubMed Central (United Kingdom)

Electron spin resonance (ESR) studies have been performed on spin-labeled model membranes aligned using the isopotential spin-dry ultracentrifugation (ISDU) method of Clark and Rothschild. This method...Full Text Available

UK PubMed Central (United Kingdom)

One of the modifiable risk factors associated with coronary heart disease (CHD) is hypercholesterolemia. This paper reviews the major plasma lipids and how they relate to coronary heart disease. Among...Full Text Available

UK PubMed Central (United Kingdom)

There is increasing evidence of a biochemical link between lipid oxidation and bone metabolism. Paraoxonase 1 (PON1) prevents the oxidation of low-density lipoprotein (LDL) and metabolizes biologically...Full Text Available

Science.gov (United States)

This journal article reports a study originally intended to examine the microbial composition of Octopus Spring and nearby vent biofilms. The article compares the lipid profiles of several genera within the Aquificales as well as measurements of the isotopic carbon fractionation associated with autotrophic and heterotrophic growth of Thermocrinis ruber. Results of the study have led to improved understanding of population structure in the Octopus Spring pink streamer community, a hyperthermophilic chemolithotrophic ecosystem in Yellowstone National Park.

International Nuclear Information System (INIS)

Using a new approach to quaternion mechanics based on De Broglie waves, it is shown that such a theory describes tachyons and that the quantum theory of tachyons should be a quaternionic one. (U.K.).

International Nuclear Information System (INIS)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A new model for computations is considered which combines the quantum computer with the chaotic dynamics amplifier, based on the logistic map. We discuss the satisfiability problem and argue that the problem can, in principle, be solved in polynomial time if one uses the new model for computations.

Energy Technology Data Exchange (ETDEWEB)

In this paper method of constructing quasi-exactly solvable models of quantum mechanics is proposed. This method is based on the use of infinite-dimensional representations of simple and semi-simple Lie algebras.

UK PubMed Central (United Kingdom)

A quantum computer (QC) can operate in parallel on all its possible inputs at once, but the amount of information that can be extracted from the result is limited by the phenomenon of wave function...Full Text Available

International Nuclear Information System (INIS)

Considered is a new type of generalized asymptotic functions, which are not functionals on some space of test functions as the Schwartz distributions. The definition of the generalized asymptotic functions is given. It is pointed out that in future the particular asymptotic functions will be used for solving some topics of quantum mechanics and quantum theory.

International Nuclear Information System (INIS)

Two avowable quantum communication schemes are proposed. One is an avowable teleportation protocol based on the quantum cryptography. In this protocol one teleports a set of one-particle states based on the availability of an honest arbitrator, the keys and the Einstein-Podolsky-Rosen pairs shared by the communication parties and the arbitrator. The key point is that the fact of the teleportation can neither be disavowed by the sender nor be denied by the receiver. Another is an avowable quantum secure direct communication scheme. A one-way Hash function chosen by the communication parties helps the receiver to validate the truth of the information and to avoid disavowing for the sender.

International Nuclear Information System (INIS)

The conventional treatment of quantum field theories including tachyons is presented, in particular the phi"4 theory. (W.D.L.).

Energy Technology Data Exchange (ETDEWEB)

Trapped ions are a near ideal system to study quantum information processing due to the high degree of control over the ion's external confinement and internal degrees of freedom. We demonstrate the key steps necessary for trapped ion quantum computing and focus on phonon-mediated entangling gates. We highlight several key algorithms implemented over the last decade with these gates and give a detailed description of Grover's quantum database search implemented with two trapped ion qubits.

International Nuclear Information System (INIS)

We study a quantum computing system using microwave photons in transmission line resonators on a superconducting chip as qubits. We show that linear optics and other controls necessary for quantum computing can be implemented by coupling to Josephson devices on the same chip. By taking advantage of the strong nonlinearities in Josephson junctions, photonic qubit interactions can be realized. We analyze the gate error rate to demonstrate that our scheme is realistic even for Josephson devices with limited decoherence times. As a conceptually innovative solution based on existing technologies, our scheme provides an integrated and scalable approach to the next key milestone for photonic qubit quantum computing.

Energy Technology Data Exchange (ETDEWEB)

In this talk, we explore the feasibility of quantum computation using continuous-variable systems by means of local measurements only. In the first part of the talk, we will identify crucial limitations that arise when starting from Gaussian cluster states. This is done by resorting to a Gaussian projected entangled pair picture as well as to notions of continuous-variable quantum repeater networks. In the second part, we look at instances in which these limitations can be overcome, and how suitable encodings of qubits in oscillators and feasible non-Gaussian resource states give rise to universal schemes for quantum computing.

Science.gov (United States)

In this paper, we proposed a novel quantum secure direct communication scheme with one-time pad in stabilizer formalism. Based on the reuse of qubit sequence, an efficient secure communication of secret messages without first producing a shared secret key can be achieved. One hence may find that the amount of private key needed for quantum communication is smaller than that in the general case. Therefore, the present protocol which is feasible with the present-day techniques may be applied to quantum communication with short-length encoding.

CERN Document Server

We study the all-optical time-control of the strong coupling between a single cascade three-level quantum emitter and a microcavity. We find that only specific arrival-times of the control pulses succeed in switching-off the Rabi oscillations. Depending on the arrival times of control pulses, a variety of exotic non-adiabatic cavity quantum electrodynamics effects can be observed. We show that only control pulses with specific arrival times are able to suddenly switch-off and -on first-order coherence of cavity photons, without affecting their strong coupling population dynamics. Such behavior may be understood as a manifestation of quantum complementarity.

International Nuclear Information System (INIS)

The propriety of the cosmic no-hair conjecture to the Bianchi-type-IX spacetime is discussed from a quantum cosmological point of view. It is shown that most, but not all, classical universes which are created quantum cosmologically are inflationary. The probability of inflation among such universes is also discussed.

CERN Document Server

We obtain a simple derivation of the optimal quantum state estimation of a two-level system using the no-signaling principle. In particular, we show that the no-signaling principle determines the unique form of the guessing probability, independently to a given figure of merit such as the fidelity or the information gain. This proves that optimal measurements for a two-level quantum system is the same for almost all figures of merit.

CERN Document Server

Two-dimensional generalization of the original peak finding algorithm suggested earlier is given. The ideology of the algorithm emerged from the well known quantum mechanical tunneling property which enables small bodies to penetrate through narrow potential barriers. We further merge this ``quantum'' ideology with the philosophy of Particle Swarm Optimization to get the global optimization algorithm which can be called Quantum Swarm Optimization. The functionality of the newborn algorithm is tested on some benchmark optimization problems.

CERN Document Server

A consistent combination of quantum geometry effects rules out a large class of models of loop quantum cosmology and their critical densities as they have been used in the recent literature. In particular, the critical density at which an isotropic universe filled with a free, massless scalar field would bounce must be well below the Planck density. In the presence of anisotropy, no model of the Schwarzschild black hole interior analyzed so far is consistent.

Energy Technology Data Exchange (ETDEWEB)

Implementation of quantum logical gates for multilevel systems is demonstrated through decoherence control under the quantum adiabatic method using simple phase modulated laser pulses. We make use of selective population inversion and Hamiltonian evolution with time to achieve such goals robustly instead of the standard unitary transformation language. (letter to the editor)

CERN Document Server

We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the energy spectra of polynomial ones. We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the energy spectra of polynomial ones.

CERN Document Server

This Chapter develops a realist information-theoretic interpretation of the nonclassical features of quantum probabilities. On this view, what is fundamental in the transition from classical to quantum physics is the recognition that \\emph{information in the physical sense has new structural features}, just as the transition from classical to relativistic physics rests on the recognition that space-time is structurally different than we thought. Hilbert space, the event space of quantum systems, is interpreted as a kinematic (i.e., pre-dynamic) framework for an indeterministic physics, in the sense that the geometric structure of Hilbert space imposes objective probabilistic or information-theoretic constraints on correlations between events, just as the geometric structure of Minkowski space in special relativity imposes spatio-temporal kinematic constraints on events. The interpretation of quantum ...

British Library Electronic Table of Contents (United Kingdom)

An aliphatic thiol ligand of CuInS2/ZnS core/shell quantum dots is replaced with a hydroxyl-terminated thiol ligand by utilizing `on-off state' of ligands during growth stage of the quantum dots. After the ligand-exchange, negligible differences were observed on both photoluminescence spectrum and luminescent quantum efficiency. The reason for the high retention of luminescent efficiency comes from no local agglomeration and no surface deterioration of QDs. It is also observed that 70% of initial ligands are exchanged by the replacing ligand, determined by FT-IR and 1H NMR. The proposed method provides the quantum dots with an excellent dispersibility in polar solvents, supported by identical luminescence decay characteristics of the QDs.

Science.gov (United States)

In this paper an efficient quantum secure direct communication (QSDC) scheme with authentication is presented, which is based on quantum entanglement and polarized single photons. The present protocol uses Einstein-Podolsky-Rosen (EPR) pairs and polarized single photons in batches. A particle of the EPR pairs is retained in the sender's station, and the other is transmitted forth and back between the sender and the receiver, similar to the ``ping-pong'' QSDC protocol. According to the shared information beforehand, these two kinds of quantum states are mixed and then transmitted via a quantum channel. The EPR pairs are used to transmit secret messages and the polarized single photons used for authentication and eavesdropping check. Consequently, because of the dual contributions of the polarized single photons, no classical information is needed. The intrinsic efficiency and total efficiency are both 1 ...

Energy Technology Data Exchange (ETDEWEB)

The construction of networks consisting of optically interconnected processing units is a promising way to scale up quantum information processing systems. To store quantum information, single trapped atoms are among the most proven candidates. By placing them in high finesse optical resonators, a bidirectional information exchange between the atoms and photons becomes possible with, in principle, unit efficiency. Such an interface between stationary and ying qubits constitutes a possible node of a future quantum network. The results presented in this thesis demonstrate the prospects of a quantum interface consisting of a single atom trapped within the mode of a high-finesse optical cavity. In a two-step process, we distribute entanglement between the stored atom and two subsequently emitted single photons. The long atom trapping times achieved in the system together with the high photon collection ...

Energy Technology Data Exchange (ETDEWEB)

This project has received DOE support since July 1, 1978. During this period, 40 papers have been published dealing predominantly with chlorophyll-photosensitized electron transfer reactions in a variety of media (solutions, polymer films, lipid bilayer membranes). The overall theme of this work has been to develop mechanistic strategies f or photochemical energy storage via chlorophyll, using the green plant photosynthetic system as a paradigm for designing in vitro systems. Microheterogeneous lipid vesicle suspensions allow ready application of time-resolved optical spectroscopy to follow the course of light-induced electron transfer processes. Both the yields and the lifetimes of electron transfer products were markedly improved in the vesicle systems. In subsequent studies, this compartmentalization was favorably manipulated by controlling the electrical charge on the membrane surface, by controlling the solubility properties of the ...

Energy Technology Data Exchange (ETDEWEB)

This study evaluates the effect of gamma radiation on the viability of fungi and actinomycetes that contaminate medicinal plants. The relationship between the total lipids of some fungi and actinomycetes and their sensitivity to gamma radiation is also investigated. The data reveal that the viable counts of these florae decrease approximately exponentially with the radiation dose, the effective dose for the elimination of these microorganisms being about 5 kGy for all the medicinal plants under study. Response of pure cultures of fungi and actinomycetes isolated from medicinal plants to increasing absorbed doses of gamma radiation indicate that an increase in radioresistance is in the following order: Streptomyces rimosus, Fusarium solani, Nocardia kuroishii. F. oxysporum, A. fumigatus, A. flavus, A. parasiticus and A. ochraceus. The total lipid contents of molds and actinomycetes have been reported to be increased by increasing the ...

British Library Electronic Table of Contents (United Kingdom)

l-Carnitine is a critical metabolite indispensable for the metabolism of lipids as it facilitates fatty acid transport into the mitochondrion where b-oxidation occurs. Human astrocytes (CCF-STTG1 cells) and hepatocytes (HepG2 cells) exposed to aluminum (Al) and hydrogen peroxide (H2O2), were characterized with lower levels of l-carnitine, diminished b-oxidation, and increased lipid accumulation compared to the controls. g-Butyrobetainealdehyde dehydrogenase (BADH) and butyrobetaine dioxygenase (BBDOX), two key enzymes mediating the biogenesis of l-carnitine, were sharply reduced during Al and H2O2 challenge. Exposure of the Al and H2O2-treated cells to a-ketoglutarate (KG), led to the recovery of l-carnitine production with the concomitant reduction in ROS levels. It appears that the chann...

British Library Electronic Table of Contents (United Kingdom)

Inhibition of adipogenesis and lipid accumulation has a very crucial role to prevent obesity. Low molecular weight (LMW) chitosan is known to inhibit fat accumulation and adipogenesis. (N,O)-sulfated chitosan is a sulfation derivative of chitosan oligomers, and its anti-obesity effect is not yet reported. In this study, it has been reported that (N,O)-sulfated chitosan significantly decreased lipid accumulation, an indicator for adipogenesis, in differentiating 3T3-L1 preadipocyte cells. Furthermore, mRNA expressions and protein levels of key adipogenic markers such as peroxisome prolifetor-activated receptor (PPAR)-@c and CCAAT-enhancer binding protein (C/EBP)-@a were considerably decreased by (N,O)-sulfated chitosan treatment. As a consequence, sulfation of LMWC remarkably increased its ...

British Library Electronic Table of Contents (United Kingdom)

Abstract:- An experimental investigation was carried out to evaluate the quality of-taralli-as a function of the type of oil used in their dough formulation. To this end, 4 types of oil (extra virgin olive oil, olive oil, olive-pomace oil, and refined palm oil) were utilized to prepare-taralli-to investigate on the lipid fraction degradation and evaluate the-taralli-acceptability by consumers. The data obtained pointed out that-taralli-manufactured with extra virgin olive oil were significantly more appreciated than those made with refined oils due to their visual appearance and odor. Moreover, with respect to the other kinds of oil, the use of extra virgin olive oil led to significantly lower values (P-< 0.05) of specific absorption at 232 and 270 nm (K232 and K270, respectively) and of t...

British Library Electronic Table of Contents (United Kingdom)

Abstract Micronutrient deficiencies are a public health concern among young children in low-income countries, and novel strategies are needed to improve the nutritional status of children at risk. One promising approach is the use of lipid-based nutrient supplements (LNS), which can be added to complementary food at the time of consumption. The optimal amount of zinc to include in LNS is uncertain, and concerns have been expressed about possible adverse effects of zinc on sensory characteristics of LNS. We conducted a series of acceptability studies of LNS containing either 0 or 10-mg of zinc per daily 20-g LNS dose among Burkinabe children 9-15 months old and their mothers. These acceptability studies included observations of children's consumption, maternal and child sensory reaction to ...

Energy Technology Data Exchange (ETDEWEB)

We revisited the quantum Zeno paradox, which claims that a generic quantum system prepared in a state which is not an eigenstate of the Hamiltonian operator and is continuously observed never decays. Since any perfectly isolated quantum system always interact with a vacuum field, we analyze the possibility of using this fact to solve the above mentioned conceptual problem. Therefore we discuss a two-level system or qubit-Bose field interaction Hamiltonians. We consider the quantum dynamics of this two-level system, prepared in the excited state interacting with a Bose field prepared in the Poincare invariant vacuum state. Using a first-order approximation in time-dependent perturbation theory, we evaluate the probability of spontaneous decay of the two-level system driven by the vacuum field. This probability is evaluated for a finite time interval. Using the standard argument to obtain the ...

Energy Technology Data Exchange (ETDEWEB)

The canonical quantum theory of gravity-quantum geometrodynamics (QG)-is applied to the homogeneous Bianchi type IX cosmological model. As a result, a framework for the quantum theory of homogeneous cosmologies is developed. We show that the theory is internally consistent and prove that it possesses the correct classical limit (the theory of general relativity). To emphasize the special role that the constraints play in this new theory, we compare it to the traditional ADM square-root and Wheeler-DeWitt quantization schemes. We show that, unlike traditional approaches, QG leads to a well-defined Schroedinger equation for the wavefunction of the universe that is inherently coupled to the expectation value of the constraint equations. This coupling to the constraints is responsible for the appearance of a coherent spacetime picture. Thus, the physical meaning of the constraints of the theory is quite different from ...

CERN Document Server

We consider the role of quantum effects in the transfer of hyrogen-like species in enzyme-catalysed reactions. This study is stimulated by claims that the observed magnitude and temperature dependence of kinetic isotope effects imply that quantum tunneling below the energy barrier associated with the transition state significantly enhances the reaction rate in many enzymes. We use a path integral approach which provides a general framework to understand tunneling in a quantum system which interacts with an environment at non-zero temperature. Here the quantum system is the active site of the enzyme and the environment is the surrounding protein and water. Tunneling well below the barrier only occurs for temperatures less than a temperature $T_0$ which is determined by the curvature of potential energy surface near the top of the barrier. We argue that for most enzymes this temperature is less than room ...

CERN Document Server

English abstract: In the "Intuitive Quantum Physics" course, we use graphical interpretations of mathematical equations and qualitative reasoning to develop and teach a simplified model of quantum physics. Our course contains three units: Wave physics, Development of a conceptual toolbox, and quantum physics. It also contains three key themes: wave-particle duality, the Schroedinger equation, and tunneling of quantum particles. Students learn most new material in lab-tutorials in which students work in small groups (3 to 3 people) on specially designed worksheets. Lecture reinforces the lab-tutorial content and focuses more on issues about the nature of science. Data show that students are able to learn some of the most difficult concepts in the course, and also that students learn to believe that there is a conceptually accessible structure to the physics in the course. German abstract: Im Kurs ...

British Library Electronic Table of Contents (United Kingdom)

Cadmium sulfide particles have been synthesized in the aqueous medium using the amino acid histidine as a stabilizing agent. These particles demonstrate the phenomenon of size quantization effect. The fluorescence of histidine-stabilized CdS was found to be enhanced and quenched by the addition of DNA bases adenine and guanine, respectively. The fluorescence enhancement of CdS in the presence of adenine has been explained on the basis of interaction between the quantum dot stabilizer and the amino group of adenine. Quenching of CdS fluorescence by guanine occurs due to interaction of the substrate with the quantum dot surface.

Energy Technology Data Exchange (ETDEWEB)

We prove that the 1984 protocol of Bennett and Brassard (BB84) for quantum key distribution is secure. We first give a key distribution protocol based on entanglement purification, which can be proven secure using methods from Lo and Chau's proof of security for a similar protocol. We then show that the security of this protocol implies the security of BB84. The entanglement purification based protocol uses Calderbank-Shor-Steane codes, and properties of these codes are used to remove the use of quantum computation from the Lo-Chau protocol. (c) 2000 The American Physical Society.

Energy Technology Data Exchange (ETDEWEB)

We present a study of the interaction between Josephson junctions in circular superconducting rings and non-classical microwaves, treating both quantum mechanically. A Hamiltonian that describes both inductive and capacitive coupling between the two systems is derived within the external field approximation. Other Hamiltonians which go beyond the external field approximation, and describe explicitly the interaction of the quantum circuit that produces the non-classical microwaves with the Josephson junction circuit, are also presented. A comparison between current experiments which use classical electromagnetic fields and the proposed experiments that use non-classical microwaves, is made. (orig.) With 6 figs., 32 refs.

International Nuclear Information System (INIS)

We propose a scheme of quantum computation with nonlinear quantum optics. Polarization states of photons are used for qubits. Photons with different frequencies represent different qubits. Single qubit rotation operation is implemented through optical elements like the Faraday polarization rotator. Photons are separated into different optical paths, or merged into a single optical path using dichromatic mirrors. The controlled-NOT gate between two qubits is implemented by the proper combination of parametric up and down conversions. This scheme has the following features: (1) No auxiliary qubits are required in the controlled-NOT gate operation; (2) No measurement is required in the course of the computation; (3) It is resource efficient and conceptually simple.

Energy Technology Data Exchange (ETDEWEB)

Several possibilities of the use of molecular models in quantum-chemical investigations of the structure of defect centers on the surfaces of oxides on nontransition elements have been illustrated. There has been a special discussion of the assumption of the local nature of the chemical interactions in these systems, which underlies such an approach, and of the consequent laws governing the formation of their lattices in the example cases of zeolites, kaolinites, and comparable boron- and aluminum-containing oxides. A quantum-chemical interpretation of the body of experimental data from investigations of the dehydroxylation of H forms of zeolites has been given. The structure of the Lewis acid centers formed as a result, and their chemisorption properties, have been discussed.

British Library Electronic Table of Contents (United Kingdom)

A problem of the catalytic activity definition for metals, binary metallic alloys, and semiconductor materials is considered within new quantum mechanical and electrodynamics approach in the electron theory of catalysis. The quantitative link between the electron structure parameters of the materials and their catalytic activity on example of simple model reactions of the following type are found: H = H+ + e, O2 + e- = O2-. Copyright 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

International Nuclear Information System (INIS)

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to continuous modulation similar to phase-shift keying in classical communication. Information is decoded by simultaneous homodyne measurement of both quadratures and requires no active choice of basis. The protocol utilizes either direct or reverse reconciliation both with and without postselection. We analyze the security of the protocol and show how to enhance it by the optimal choice of all variable parameters of the quantum signal.

CERN Document Server

We investigate the relation between the symmetries of a quantum system and its topological quantum numbers, in a general C*-algebraic framework. We prove that, under suitable assumptions on the symmetry algebra, there exists a generalization of the Bloch-Floquet transform which induces a direct-integral decomposition of the algebra of observables. Such generalized transform selects uniquely the set of "continuous sections" in the direct integral, thus yielding a Hilbert bundle. The emerging geometric structure provides some topological invariants of the quantum system. Two running examples provide an Ariadne's thread through the paper. For the sake of completeness, we review two related theorems by von Neumann and Maurin and compare them with our result.

CERN Document Server

We analyze the driven resonantly coupled Jaynes-Cummings model in terms of a quasienergy approach by switching to a frame rotating with the external modulation frequency and by using the dressed atom picture. A quasienergy surface in phase space emerges whose level spacing is governed by a rescaled effective Planck constant. Moreover, the well-known multiphoton transitions can be reinterpreted as resonant tunneling transitions from the local maximum of the quasienergy surface. Most importantly, the driving defines a quasienergy well which is nonperturbative in nature. The quantum mechanical quasienergy state localized at its bottom is squeezed. In the Purcell limited regime, the potential well is metastable and the effective local temperature close to its minimum is uniquely determined by the squeezing factor. The activation occurs in this case via dressed spin flip transitions rather than via quantum activation as in other driven nonlinear ...

International Nuclear Information System (INIS)

This topical review provides an overview of quantum dot micropillars and their application in cavity quantum electrodynamics (cQED) experiments. The development of quantum dot micropillars is motivated by the study of fundamental cQED effects in solid state and their exploitation in novel light sources. In general, light-matter interaction occurs when the dipole of an emitter couples to the ambient light field. The corresponding coupling strength is strongly enhanced in the framework of cQED when the emitter is located inside a low mode volume microcavity providing three-dimensional photon confinement on a length scale of the photon wavelength. In addition, coherent coupling between light and matter, which is essential for applications in quantum information processing, can be achieved when dissipative losses, predominantly due to photon leakage out of the cavity, are strongly reduced. In this paper, we ...

International Nuclear Information System (INIS)

A quantum mechanical analysis of the guided light in integrated photonics waveguides is presented. The analysis is made starting from one-dimensional (1D) guided vector modes by taking into account the modal orthonormalization property on a cross section of an optical waveguide, the vector structure of the guided optical modes and the reversal-time symmetry in order to quantize the 1D vector modes and to derive the quantum momentum operator and the Heisenberg equations. The results provide a quantum-consistent formulation of the linear and nonlinear quantum light propagations as a function of forward and backward creation and annihilation operators in integrated photonics. As an illustration, an application to an integrated nonlinear directional coupler is given, that is, both the nonlinear momentum and the Heisenberg equations of the nonlinear coupler are derived.

Energy Technology Data Exchange (ETDEWEB)

We introduce a novel scheme for one-way quantum computing (QC) based on the use of information encoded qubits in an effective cluster state resource. With the correct encoding structure, we show that it is possible to protect the entangled resource from phase damping decoherence, where the effective cluster state can be described as residing in a decoherence-free subspace (DFS) of its supporting quantum system. One-way QC then requires either single or two-qubit adaptive measurements. As an example where this proposal can be realized, we describe an optical lattice set-up where the scheme provides robust quantum information processing. We also outline how one can adapt the model to provide protection from other types of decoherence.

Science.gov (United States)

... Assuming isotropic emission, the 25' half angle cone represents only -9% [= 1/(2(ngaas/nopticglue) 2)] of the spontaneous radiation. ...

Energy Technology Data Exchange (ETDEWEB)

The difference between the two nonclassical lights, i.e., the squeezed state and number-phase minimum uncertainty state (NUS) is discussed. The four different generation principles for NUS are described. They are: unitary evolution using self-phase modulation; nonunitary state reduction by the first kind measurement; controlled state reduction by quantum correlation measurement-feedback, and high saturated laser oscillation with suppressed-pump-noise. The constant current-driven semiconductor laser based on the last principle generated the NUS with photon number noise reduced below the standard quantum limit by 40 percent in the entire frequency region from dc to 1.1 GHz. Several applications of NUS including quantum communication, quantum mechanical computers and interferometric gravitational detection are discussed briefly. This presentation is represented by viewgraphs only.

Science.gov (United States)

Excitonic transitions in metalorganic vapor phase epitaxially grown In[sub [ital x

CERN Document Server

The Arnowitt-Deser-Misner canonical formulation of general relativity is extended to the covariant brane-world theory in arbitrary dimensions. The exclusive probing of the extra dimensions makes a substantial difference, allowing for the construction of a non-constrained canonical theory. The quantum states of the brane-world geometry are defined by the Tomonaga-Schwinger equation, whose integrability conditions are determined by the classical perturbations of submanifolds contained in the Nash's differentiable embedding theorem. In principle, quantum brane-world theory can be tested by current experiments in astrophysics and by near future laboratory experiments at Tev energy. The implications to the black-hole information loss problem, to the accelerating cosmology, and to a quantum mathematical theory of four-sub manifolds are briefly commented.

CERN Document Server

A prescription is given for computing anomalous dimensions of single trace operators in SYM at strong coupling and large $N$ using a reduced model of matrix quantum mechanics. The method involves treating some parts of the operators as "BPS condensates" which, in certain limit, have a dual description as null geodesics on the $S^5$. In the gauge theory, the condensate is similar to a representative of the chiral ring and it is described by a background of commuting matrices. Excitations around these condensates correspond to excitations around this background and take the form of ``string bits" which are dual to the "giant magnons" of Hofman and Maldacena. In fact, the matrix model approach gives a {\\it quantum} description of these string configurations and explains why the infinite momentum limit suppresses the quantum effects. This method allows, not only to derive part of the classical sigma model Hamiltonian of the ...

Energy Technology Data Exchange (ETDEWEB)

Linear-optical passive (LOP) devices and photon counters are sufficient to implement universal quantum computation with single photons, and particular schemes have already been proposed. In this paper we discuss the link between the algebraic structure of LOP transformations and quantum computing. We first show how to decompose the Fock space of N optical modes in finite-dimensional subspaces that are suitable for encoding strings of qubits and invariant under LOP transformations (these subspaces are related to the spaces of irreducible unitary representations of U (N). Next we show how to design in algorithmic fashion LOP circuits which implement any quantum circuit deterministically. We also present some simple examples, such as the circuits implementing a cNOT gate and a Bell state generator/analyser.

CERN Document Server

The quantum nature of the electromagnetic field imposes a fundamental limit on the sensitivity of optical precision measurements such as spectroscopy, microscopy, and interferometry. The so-called quantum limit is set by the zero-point fluctuations of the electromagnetic field, which constrain the precision with which optical signals can be measured. In the world of precision measurement, laser-interferometric gravitational wave (GW) detectors are the most sensitive position meters ever operated, capable of measuring distance changes on the order of 10^-18 m RMS over kilometer separations caused by GWs from astronomical sources. The sensitivity of currently operational and future GW detectors is limited by quantum optical noise. Here we demonstrate a 44% improvement in displacement sensitivity of a prototype GW detector with suspended quasi-free mirrors at frequencies where the sensitivity is shot-noise-limited, by ...

International Nuclear Information System (INIS)

The water soluble, photolabile nitrene precursor, azidonaphthalene-2,7-disulfonic acid (ANDS) was encapsulated in small unilamellar, isoelectric (egg PC) or negatively charged (egg PC + dihexadecylphosphate) liposomes. The individual and combined effects of heme-proteins and UV irradiation on the fluorescence of these vesicles under aerobic conditions were studied. Consistent with the catalytic action of heme-proteins on lipid peroxidation and peroxide decomposition, addition of cytochrome c (positively charged) or catalase (negatively charged) to the vesicles elicited immediate formation of a fluorescence band at 470 nm, characteristic of Schiff bases that form from aldehyde byproducts of decomposing hydroperoxides. Ultraviolet irradiation of liposomes caused no significant changes in the fluorescence spectrum, in spite of the radiolysis of ANDS inside the vesicles with consequent formation of nitrene radicals. When isoelectric vesicles were irradiated with UV ...

UK PubMed Central (United Kingdom)

Retinal pigment epithelial (RPE) cells, derived from the neuroectoderm, biosynthesize the novel lipid mediator neuroprotectin D1 (NPD1) from docosahexaenoic acid (DHA) in response to oxidative...Full Text Available

UK PubMed Central (United Kingdom)

In monocytes, sulfatide, a lipid from Mycobacterium tuberculosis, blocked priming for enhanced release of superoxide (O2-) by the macrophage activating factors lipopolysaccharide, gamma interferon,...Full Text Available

International Nuclear Information System (INIS)

It was shown that the incorporation of "1"4C-linoleic acid in cerebrosides of normal and psoriatic human skin is different. In psoriatic epidermis and corium the turnover of this fatty acid is significantly elevated. It is suggested that in psoriasis the epidermal cell is not able to build up a regular carbohydrate sequences of lipids because the false carbohydrate chain activates the degradation of glycolipids and in compensating for the increased degradation raises the synthesis rate of glycolipids. (orig./MG).

International Nuclear Information System (INIS)

We studied the effect of extracellular Ca"2"+ concentration ([Ca"2"+]_e) on adipocyte differentiation. Preadipocytes exposed to continuous [Ca"2"+]_e higher than 2.5 mmol/l accumulated little or no cytoplasmic lipid compared to controls in 1.8 mmol/l [Ca"2"+]_e. Differentiation was monitored by Oil Red O staining of cytoplasmic lipid and triglyceride assay of accumulated lipid, by RT-PCR analysis of adipogenic markers, and by the activity of glycerol-3-phosphate dehydrogenase (GPDH). Elevated [Ca"2"+]_e inhibited expression of peroxisome proliferator-activated receptor #gamma#, CCAAT/enhancer binding protein #alpha#, and steroid regulatory binding element protein. High [Ca"2"+]_e significantly inhibited differentiation marker expression including adipocyte fatty acid binding protein, and GPDH. The decrease in Pref-1 expression that accompanied differentiation also was prevented by high [Ca"2"+]_e. Treatment of 3T3-L1 cells ...

Environmental Research Database

DescriptionThe plant enzyme polyphenol oxidase (PPO) has been demonstrated to reduce both proteolysis and lipolysis during the ensiling of red clover. The purpose of this work is to explore the potential for exploiting this beneficial trait in other dietary regimes for grazing ruminants. These studies will focus on the development of new strategies for forage management and livestock feeding by increasing the efficiency of feed protein-N utilisation and reducing saturated fatty acid production by ruminan [continued...

UK PubMed Central (United Kingdom)

Eight rabbits and 24 guinea-pigs were exposed to a silica dust cloud of about 40,000 pp./ml. (0·3-3·0 μ) and killed at four-weekly intervals up to 30 weeks. The guinea-pigs showed...Full Text Available

Science.gov (United States)

Recently, Wang et al. proposed a three-party simultaneous quantum secure direct communication (3P-SQSDC) scheme with EPR pairs, which enables three involved parties to exchange their secret messages simultaneously by using an EPR pair. This work proposed an enhancement on Wang et al.'s scheme. With the enhancement, the communications in the improved 3P-SQSDC can be paralleled and thus improves the protocol efficiency.

Energy Technology Data Exchange (ETDEWEB)

The mathematical apparatus of quantum-mechanical angular momentum (re)coupling, developed originally to describe spectroscopic phenomena in atomic, molecular, optical and nuclear physics, is embedded in modern algebraic settings which emphasize the underlying combinatorial aspects. SU(2) recoupling theory, involving Wigner's 3nj symbols, as well as the related problems of their calculations, general properties, asymptotic limits for large entries, nowadays plays a prominent role also in quantum gravity and quantum computing applications. We refer to the ingredients of this theory-and of its extension to other Lie and quantum groups-by using the collective term of 'spin networks'. Recent progress is recorded about the already established connections with the mathematical theory of discrete orthogonal polynomials (the so-called Askey scheme), providing powerful tools based on ...

International Nuclear Information System (INIS)

Correlation characteristics of quantum noise on the shadow radiation image (RI) of the object under nondestructive testing are studied. Mathematical model of RI occasional distortions is derived. The model takes into account the parameters of object under testing and of radiation beam by radiation quanta flux density. The results obtained can be used as a component in the process of investigation of various radiation testing systems

Energy Technology Data Exchange (ETDEWEB)

In this paper we establish that every quantum field theory satisfying some basic axioms possesses a weak quasi Hopf algebra as gauge symmetry. We use a reconstruction theorem to find this symmetry algebra and show how it is sed to build a gauge covariant field algebra. We investigate the question of why this generality is necessary. The non-uniqueness of the reconstruction process is interpreted and a cohomological classification of possible global gauge symmetries is given. (author)

CERN Document Server

Two crucial properties of QCD, confinement and chiral symmetry breaking, cannot be understand within the context of conventional Feynman perturbation theory. Non-perturbative phenomena enter the theory in a fundamental way at both the classical and quantum level. Over they years a coherent qualitative picture of the interplay between chiral symmetry, quantum mechanical anomalies, and the lattice has emerged and is reviewed here.

International Nuclear Information System (INIS)

Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.

Energy Technology Data Exchange (ETDEWEB)

We present a set of exact solutions for quantum Bianchi type-IX anisotropic cosmological models (including the Taub model) of the form {Psi}={ital We}{sup {minus}{ital S}}. These solutions are spread over all values of anisotropy near the singularity, but at larger values of the radius of the universe they are strongly peaked around the {ital k}=+1 Friedmann-Robertson-Walker model.

CERN Document Server

The quantum $N$-body problem is studied in the context of nonrelativistic quantum mechanics with a one-dimensional deformed Heisenberg algebra of the form $[\\hat x,\\hat p]=i(1+\\beta \\hat p^2)$, leading to the existence of a minimal observable length $\\sqrt\\beta$. For a generic pairwise interaction potential, analytical formulas are obtained that allow to estimate the ground-state energy of the $N$-body system by finding the ground-state energy of a corresponding two-body problem. It is first shown that, in the harmonic oscillator case, the $\\beta$-dependent term grows faster with $N$ than the $\\beta$-independent one. Then, it is argued that such a behavior should be observed also with generic potentials and for $D$-dimensional systems. In consequence, quantum $N$-body bound states might be interesting places to look at nontrivial manifestations of a minimal length since, the more particles are present, the more the ...

Energy Technology Data Exchange (ETDEWEB)

The quantum behavior of the vacuum Bianchi type-IX universe with the cosmological constant is investigated in terms of the Ashtekar variables. An exact solution to the quantum Hamiltonian constraint in the holomorphic representation is given. This solution reduces to the Hartle-Hawking wave function in the spatially isotropic sector and extends in the triad representation to the classically forbidden region where the determinant of the spatial metric becomes negative. The analysis of the quantum Robertson-Walker universe indicates that if the superspace is extended to such a classically forbidden region, the holomorphic representation picks up some restricted class of solutions in general. This observation leads to a new ansatz on the boundary condition of the Universe. In particular, the behavior of the Lorentzian and Euclidean WKB orbits corresponding to the solution suggests a new picture on the semiclassical behavior of ...

International Nuclear Information System (INIS)

We consider the spin-k/2 XXZ model in the antiferromagnetic regime using the free-field realization of the quantum affine algebra U_q(sl_2) of level k. We give a free-field realization of the type-II q-vertex operator, which describes creation and annihilation of physical particles in the model. By taking a trace of the type-I and type-II q-vertex operators over the irreducible highest-weight representation of U_q(sl_2), we also derive an integral formula for form factors in this model. Investigating the structure of poles, we obtain a residue formula for form factors, which is a lattice analog of the higher-spin extension of Smirnov's formula in the massive integrable quantum field theory. This result as well as the quantum deformation of the Knizhnik-Zamolodchikov equation for form factors shows a deep connection in the mathematical structure of the integrable lattice models and the massive integrable ...

Energy Technology Data Exchange (ETDEWEB)

Recently, the public has become aware of keywords like ''Quantum computer'' or ''Quantum cryptography''. Regarding their potential application in solid state based quantum information processing and their overall benefit in fundamental research quantum dots have gained more and more public interest. In this context, quantum dots are often referred to as ''artificial atoms'', a term subsuming their physical properties quite nicely and emphasizing the huge potential for further investigations. The basic mechanism to be considered is the theoretical model of a two-level system. A quantum dot itself represents this kind of system quite nicely, provided that only the presence or absence of a single exciton in the ground state of that structure is regarded. This ...

CERN Document Server

We discuss three possible ways to address quantum physics behind chiral magnetic effect and electric charge fluctuation patterns in heavy ion collisions. The first one makes use of P-parity violation probed by local order parameters, the second considers CME in quantum measurement theory framework and the third way is to study P-odd * P-odd contributions to P-even observables. In the latter approach relevant form-factor is extracted and computed for weak magnetic field in confinement region and for free quarks in strong field regime. It is shown that the effect is negligible in the former case. We also discuss saturation effect - charge fluctuation asymmetry for free fermions reaches constant value at asymptotically large fields.

CERN Document Server

We prove an analogue of the MacMahon Master Theorem for the right quantum superalgebras. In particular, we obtain a new and simple proof of this theorem for the right quantum algebras. In the super case the theorem is then used to construct higher order Sugawara operators for the affine Lie superalgebra \\hat gl(m|n) in an explicit form. The operators are elements of a completed universal enveloping algebra of \\hat gl(m|n) at the critical level. They occur as the coefficients in the expansion of a noncommutative Berezinian and as the traces of powers of generator matrices. The same construction yields higher Hamiltonians for the Gaudin model associated with the Lie superalgebra gl(m|n).

British Library Electronic Table of Contents (United Kingdom)

In this Letter, we demonstrate the application of time-resolved fluorescence anisotropy measurements to detect solution state hybridization of streptavidin conjugate (CdSe)ZnS quantum dots (QD). The study was performed on samples containing 10nM QD incubated with 800nM DNA. We show that the rotational correlation time of QD-DNA constructs increases significantly upon hybridization with values of 330ns (QD-ssDNA) and 1.3ms (QD-dsDNA), corresponding to a diameter of 14nm and 23nm respectively. The present study opens a new modality for hybridization detection using quantum dots.

CERN Document Server

We use the semi-classical approximation in perturbative scalar quantum electrodynamics to calculate the quantum correction to the Larmor radiation formula to first order in Planck's constant in the non-relativistic approximation, choosing the initial state of the charged particle to be a momentum eigenstate. We calculate this correction in two cases: in the first case the charged particle is accelerated by a time-dependent but space-independent vector potential whereas in the second case it is accelerated by a time-independent vector potential which is a function of one spatial coordinate. We find that the corrections in these two cases are different even for a charged particle with the same classical motion. The correction in each case turns out to be non-local in time in contrast to the classical approximation.

CERN Document Server

A new particle swarm optimization (PSO) technique for electromagnetic applications is proposed. The method is based on quantum mechanics rather than the Newtonian rules assumed in all previous versions of PSO, which we refer to as classical PSO. A general procedure is suggested to derive many different versions of the quantum PSO algorithm (QPSO). The QPSO is applied first to linear array antenna synthesis, which is one of the standard problems used by antenna engineers. The performance of the QPSO is compared against an improved version of the classical PSO. The new algorithm outperforms the classical one most of the time in convergence speed and achieves better levels for the cost function. As another application, the algorithm is used to find a set of infinitesimal dipoles that produces the same near and far fields of a circular dielectric resonator antenna (DRA). In addition, the QPSO method is employed to find an equivalent circuit model ...

International Nuclear Information System (INIS)

Complex numbers are an intrinsic part of the mathematical formalism of quantum theory and are perhaps its most characteristic feature. In this article, we show that the complex nature of the quantum formalism can be derived directly from the assumption that a pair of real numbers is associated with each sequence of measurement outcomes, with the probability of this sequence being a real-valued function of this number pair. By making use of elementary symmetry conditions, and without assuming that these real number pairs have any other algebraic structure, we show that these pairs must be manipulated according to the rules of complex arithmetic. We demonstrate that these complex numbers combine according to Feynman's sum and product rules, with the modulus-squared yielding the probability of a sequence of outcomes.

CERN Document Server

The problem of a spin 1 charged particle with electromagnetic polarizability, obeying a generalized 15-component quantum mechanical equation, is investigated in presence of the external Coulomb potential. With the use of the Wigner's functions techniques, separation of variables in the spherical tetrad basis is done and the 15-component radial system is given. It is shown that there exists a class of quantum states for which the additional characteristics, polarizability, does not manifest itself anyhow; at this the energy spectrum of the system coincides with the known spectrum of the scalar particle. For j=0 states, a 2-order differential equation is derived, it contains an additional potential term 1/r^{4}. In analogous approach wave functions the generalized particle are examined in presence of external Dirac monopole field. It is shown that there exists one special state with minimal conserved quantum number j_{min}. ...

Energy Technology Data Exchange (ETDEWEB)

Many-particle confinement (localization) is studied for a 1D system of spinless fermions with nearest-neighbour hopping and interaction, or equivalently, for an anisotropic Heisenberg spin-1/2 chain. This system is frequently used to model quantum computers with perpetually coupled qubits. We construct a bounded sequence of site energies that leads to strong single-particle confinement of all states on individual sites. We show that this sequence also leads to a confinement of all many-particle states in an infinite system for a time that scales as a high power of the reciprocal hopping integral. The confinement is achieved for strong interaction between the particles while keeping the overall bandwidth of site energies comparatively small. The results show the viability of quantum computing with time-independent qubit coupling.

CERN Document Server

We report on a two-photon interference experiment in a quantum relay configuration using two picosecond regime PPLN waveguide based sources emitting paired photons at 1550 nm. The results show that the picosecond regime associated with a guided-wave scheme should have important repercussions for quantum relay implementations in real conditions, essential for improving both the working distance and the efficiency of quantum cryptography and networking systems. In contrast to already reported regimes, namely femtosecond and CW, it allows achieving a 99% net visibility two-photon interference while maintaining a high effective photon pair rate using only standard telecom components and detectors.

CERN Document Server

We review various field theory approaches to the description of neutrino oscillations in vacuum and external fields. First we discuss a relativistic quantum mechanics based approach which involves the temporal evolution of massive neutrinos. To describe the dynamics of the neutrinos system we use exact solutions of wave equations in presence of an external field. It allows one to exactly take into account both the characteristics of neutrinos and the properties of an external field. In particular, we examine flavor oscillations an vacuum and in background matter as well as spin flavor oscillations in matter under the influence of an external electromagnetic field. Moreover we consider the situation of hypothetical nonstandard neutrino interactions with background fermions. In the case of ultrarelativistic particles we reproduce an effective Hamiltonian which is used in the standard quantum mechanical approach for the description of neutrino ...

British Library Electronic Table of Contents (United Kingdom)

By assuming that not only counter-ions but DNA molecules as well are thermally distributed according to a Boltzmann law, we propose a modified Poisson-Boltzmann equation, at the classical level, as a starting point to compute the effects of quantum fluctuations of the electric field on the interaction among DNA-cation complexes. The latter are modeled here as infinite one-dimensional wires (?-functions). Our goal is to single out such quantum-vacuum-driven interaction from the counterion-induced and water-related interactions. We obtain a universal, frustration-free Casimir-like (codimension 2) interaction that extensive numerical analysis show to be a good candidate to explain the formation and stability of DNA aggregates. Such Casimir energy is computed for a variety of configurations of...

DEFF Research Database (Denmark)

We propose a new physical implementation of spin qubits for quantum information processing, namely defect states in antidot lattices defined in the two-dimensional electron gas (2DEG) at a semiconductor heterostructure. Calculations of the band structure of a periodic antidot lattice are presented. A point defect is created by removing a single antidot, and calculations show that localized states form within the defect, with an energy structure which is robust against thermal dephasing. The exchange coupling between two electrons residing in two tunnel-coupled defect states is calculated numerically. We find results reminiscent of double quantum dot structures, indicating that the suggested structure is a feasible physical implementation of spin qubits.

CERN Document Server

This contribution reviews a selection of findings on atomic density functions and discusses ways for reading chemical information from them. First an expression for the density function for atoms in the multi-configuration Hartree--Fock scheme is established. The spherical harmonic content of the density function and ways to restore the spherical symmetry in a general open-shell case are treated. The evaluation of the density function is illustrated in a few examples. In the second part of the paper, atomic density functions are analyzed using quantum similarity measures. The comparison of atomic density functions is shown to be useful to obtain physical and chemical information. Finally, concepts from information theory are introduced and adopted for the comparison of density functions. In particular, based on the Kullback--Leibler form, a functional is constructed that reveals the periodicity in Mendeleev's table. Finally a quantum similarity ...

British Library Electronic Table of Contents (United Kingdom)

We report on characterization of a set of AlGaN/GaN multiple-quantum-well (MQW) photodetectors. The model structure used in the calculation is the p-i-n heterojunction with 20 AlGaN/GaN MQW structures in i-region. The MQW structures have 2nm GaN quantum well width and 15nm AlxGa1-xN barrier width. The cutoff wavelength of the MQW photodetectors can be tuned by adjusting the well width and barrier height. Including the polarization field effects, on increasing Al mole fraction, the transition energy decreases, the total noise increases, and the responsivity has a red shift, and so the detectivity decreases and has a red shift.

International Nuclear Information System (INIS)

The rates of spontaneous interbilayer and transbilayer exchange of ["3H]dimyristoylphosphatidylcholine (["3H]DMPC) were examined in the DMPC and DMPC/dimyristoylphosphatidylethanolamine (DMPE) large unilamellar vesicles in the liquid-crystalline-, gel-, and mixed-phase states. DMPC desorption rates from either gel or liquid-crystalline phases containing DMPE are very similar to the corresponding rates from pure DMPC gel or liquid-crystalline phases. The authors proposed that the DMPC/DSPC behavior results from packing defects in gel phases composed of both DMPC and DSPC molecules because of the four-carbon difference in the acyl chain lengths of the two species. The present results strongly support this hypothesis because no such anomalous behavior is observed in DMPC/DMPE, which is similar to DMPC/DSPC in phase behavior but does not have the chain length difference. These results are not consistent with lipid headgroup dehydration as the major energetic barrier to ...

Science.gov (United States)

In this work, we query the Chlamydomonas reinhardtii copper regulon at a whole-genome level. Our RNA-Seq data simulation and analysis pipeline validated a 2-fold cutoff and 10 RPKM (reads per kilobase of mappable length per million mapped reads) (~1 mRNA per cell) to reveal 63 CRR1 targets plus another 86 copper-responsive genes. Proteomic and immunoblot analyses captured 25% of the corresponding proteins, whose abundance was also dependent on copper nutrition, validating transcriptional regulation as a major control mechanism for copper signaling in Chlamydomonas. The impact of copper deficiency on the expression of several O2-dependent enzymes included steps in lipid modification pathways. Quantitative lipid profiles indicated increased polyunsaturation of fatty acids on thylakoid membrane digalactosyldiglycerides, indicating a global impact of copper deficiency on the photosynthetic apparatus. Discovery of a putative plastid copper chaperone ...

Energy Technology Data Exchange (ETDEWEB)

The lipid obtained by the toluene extraction of a dried raw Atlanta sewage sludge by the Soxhlet method, was pyrolyzed over activated alumina at atmospheric pressure. A range of weight hourly space velocities (WHSV) from 0.22-1.60/h and a range of temperatures from 400-480[degree]C were selected. A 70 wt % yield of light liquid hydrocarbons was obtained at a WHSV of 0.46/h and 450[degree]C. The sulfur and nitrogen contents of the pyrolysis products were much lower than products from direct liquefaction of sludge. Infrared spectra and [sup 13]C nuclear magnetic resonance confirmed the absence of carbonyl groups in the products. Gas chromatography showed a uniform hydrocarbon chain length distribution across the C[sub 7] to C[sub 17] mass range. The gas product consisted mainly of carbon dioxide and hydrocarbons. Lauric acid was used as a model to study the decarboxylation. The effects of catalyst loading and catalyst moisture content were investigated for the ...

International Nuclear Information System (INIS)

To elucidate the mechanism of sunlight-induced skin damage, guinea pigs exposed to UV light (280-320 nm, UV B, 4J/cm"2) and a homogenate of the epidermis was examined by means of the thiobarbituric acid (TBA) test. Three hours after the exposure, TBA-malondialdehyde adducts had increased while glutathione reductase activity had decreased, indicating lipid peroxidation. To detect the initial species, spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was applied to a suspension of illuminated epidermal cells (0.5 J/cm"2). An ESR signal obtained only with irradiation comprised a 1 : 2 : 2 : 1 quartet [a (N) =a (#beta#H) =1.49 mT] attributable to a spin adduct of hydroxyl radicals. These results suggest that sunlight exposure of skin may lead to hydroxyl radical generation and simultaneous lipid peroxidation. (author).

Science.gov (United States)

The aim of present study was to evaluate antioxidant property of Glycyrrhiza glabra root extracts using in vitro models. The dose-dependent aqueous and ethanolic extracts demonstrated the scavenging activity against nitric oxide (concentration that caused 50% inhibition of nitric oxide radicals [IC(50)]=72 and 62.1 microg/ml, respectively), superoxide (IC(50)=64.2 and 38.4 microg/ml, respectively), hydroxyl (IC(50)=81.9 and 63 microg/ml, respectively), DPPH (IC(50)=43.6 and 28.3 microg/ml, respectively) and ABTS(*+) (IC(50)=77.3 and 57.2 microg/ml, respectively) radicals. Further, both extracts showed strong reducing power and iron-chelating capacities. In the Fe(2+)/ascorbate system, both extracts were found to inhibit mitochondrial fraction lipid peroxidation. In copper-catalyzed human serum and low-density lipoprotein oxidation models, both extracts significantly (P<0.05) lengthened the lag phase along with a decline in the oxidation rate, conjugated dienes, ...

International Nuclear Information System (INIS)

Cadmium is an environmental toxic metal implicated in human diseases. The mechanism of its toxicity is not fully understood. Therefore, the role of cadmium in renal toxicity, and the protective role of selenium against this toxicity were investigated. Forty-five male rats were used through out the study and divided into three groups of 15. The first group received saline solution daily for 10 days. The second group, received cadmium chloride (CdCl_2) (2 mg/kg body weight) intraperitoneally daily for a period of 10 days. The third group, received sodium selenite (1 mg/kg body weight, twice a day) and CdCl_2 (once a day) for a period of 10 days. The results showed that cadmium treatment increased renal lipid peroxidation (measured as malondialdehyde, MDA) which was associated with a significant decrease in the antioxidant systems such as reduced glutathione levels and the activities of glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). On the other hand, ...

Science.gov (United States)

A plethora of experimental studies use mtDNA as a marker of demographic processes without questioning the possibility that selection may bias their interpretations. We studied four lines of Drosophila melanogaster that have a standardized nuclear DNA but variable mtDNA. We completed the sequencing of the mitochondrial genomes (excluding the A+T rich region) and compiled the differences. We then assayed male influence on oviposition, starvation resistance, lipid proportion and physical activity. We discuss these results in terms of the known differences between the lines and conclude that naturally occurring mtDNA variants in D. melanogaster are expressed at the level of the organismal phenotype. PMID:21757031

Science.gov (United States)

A series of pyrrolo[2,3-d]pyrimidine-2,4-diones and intermediates was tested for anticonvulsant activity in mice. Eleven of the 15 compounds possessed anticonvulsant activity against pentylenetetrazol-induced convulsions. One compound afforded more anticonvulsant protection against pentylenetetrazol than did trimethadione (67 and 50%, respectively). A suspension of this compound was found to be as effective as a solution in producing anticonvulsant activity. The results suggest that the nitrile analogs were more potent compared to the carbamyl analog due to higher lipid solubility. PMID:7373552

International Nuclear Information System (INIS)

Incorporation of tritium into body constituent molecules from tritiated water and its in vivo behaviors were studies using rats. In single administration of HTO, "3H behaviors were studied in lipids that are rich in hydrogen. Incorporation of "3H into the lipid fraction from HTO and its release differed by each organ and by the type of lipid components. Of routes of administration, the oral and parenteral routes showed same results, and no prominent difference was noted by inhalation. By consecutive administration, the urine "3H concentration showed no difference according to the route, but increased as the concentration of administered HTO increased. When administration was discontinued after the urine "3H concentration reached a plateau, the biological half-life was about 4.5 days, almost in agreement with the value by single administration. In relation to water intake, increase in the urine volume and accompanying ...

Science.gov (United States)

The adipocytokine adiponectin is released by adipocytes upon activation of the peroxisome proliferator-activated receptor gamma (PPAR gamma). PPAR gamma has binding sites for thiazolidinediones and free fatty acids (FFAs). To evaluate if adiponectin serum concentrations are synergistically regulated by FFAs and thiazolidinediones IN VIVO plasma FFAs were acutely elevated in healthy subjects pre-treated with rosiglitazone or placebo. Sixteen healthy male subjects (23-37 years) were included in this double-blind, randomized, placebo-controlled parallel-group study. Rosiglitazone 8 mg or placebo was administered daily for 21 days. On the last day plasma FFA concentrations were increased by an intravenous triglyceride/heparin infusion. Blood for determination of adiponectin, C-reactive protein (CRP), leptin, resistin, FFAs, glucose, and insulin was drawn at baseline and on day 21 before and after 5 hours of triglyceride/heparin infusion. Adiponectin concentrations increased and FFA levels ...

CERN Document Server

We use a superspin Hamiltonian defined on an infinite-dimensional Fock space with positive definite scalar product to study localization and delocalization of noninteracting spinless quasiparticles in quasi-one-dimensional quantum wires perturbed by weak quenched disorder. Past works using this approach have considered a single chain. Here, we extend the formalism to treat a quasi-one-dimensional system: a quantum wire with an arbitrary number of channels coupled by random hopping amplitudes. The computations are carried out explicitly for the case of a chiral quasi-one-dimensional wire with broken time-reversal symmetry (chiral-unitary symmetry class). By treating the space direction along the chains as imaginary time, the effects of the disorder are encoded in the time evolution induced by a single site superspin (non-Hermitian) Hamiltonian. We obtain the density of states near the band center of an infinitely long ...

CERN Document Server

Towards the end of the 19th century, Kelvin pronounced as the "clouds of physics" 1) the failure of the Michelson-Morely experiment to detect an ether wind, 2) the violation of the classical mechanical equipartition theorem in statistical thermodynamics. And he believed that the removal of these clouds would bring physics to an end. But as we know, the removal of these clouds led to the two great breakthoughts of modern physics: 1) The theory of relativity, and 2) to quantum mechanics. Towards the end of the 20th century more clouds of physics became apparent. They are 1) the riddle of quantum gravity, 2) the superluminal quantum correlations, 3) the small cosmological constant. Furthermore, there is the riddle of dark energy making up 70% of the physical universe, the non-baryonic cold dark matter making up 26% and the very small initial entropy of the universe. An attempt is made to explain the importance of these clouds ...

Energy Technology Data Exchange (ETDEWEB)

It is shown that within the framework of the Kershaw stochastic model generalized by the author to the relativistic case a Feynman-type process may be constructed which can formally be understood as a diffusion phenomenon in Euclidean space. This makes it possible to introduce a real probability measure in the scheme of quantum mechanics proposed by Feynman.

International Nuclear Information System (INIS)

This introductory text treats thermodynamics as an incomplete description of quantum systems with many degrees of freedom. Its main goal is to show that the approach to equilibrium -with equilibrium characterized by maximum ignorance about the open system of interest- neither requires that many particles nor is the precise way of partitioning, relevant for the salient features of equilibrium and equilibration. Furthermore, the text depicts that it is indeed quantum effects that are at work in bringing about thermodynamic behavior of modest-sized open systems, thus making Von Neumann's concept of entropy appear much more widely useful than sometimes feared, far beyond truly macroscopic systems in equilibrium. This significantly revised and expanded second edition pays more attention to the growing number of applications, especially non-equilibrium phenomena and thermodynamic processes of the nano-domain. In addition, to improve readability and ...

CERN Document Server

We review the interplay of frustration and strong electronic correlations in quasi-two-dimensional organic charge transfer salts, such as k-(BEDT-TTF)_2X and Et_nMe_{4-n}Pn[Pd(dmit)2]2. These two forces drive a range of exotic phases including spin liquids, valence bond crystals, pseudogapped metals, and unconventional superconductivity. Of particular interest is that in several materials there is a direct transition as a function of pressure from a spin liquid Mott insulating state to a superconducting state. Experiments on these materials raise a number of profound questions about the quantum behaviour of frustrated systems, particularly the intimate connection between spin liquids and superconductivity. Insights into these questions have come from a wide range of theoretical techniques including first principles electronic structure, quantum many-body theory and quantum field theory. In this review we introduce the basic ...

International Nuclear Information System (INIS)

A Monte Carlo simulation of the vacuum Bianchi type-IX (mixmaster) cosmology yields a significant correlation between large universe volume and high anisotropy. An analog of the model's chaotic classical behavior is seen in the break up of the universe wave function at large volume into fingers in the corners of the minisuperspace anisotropy potential.

UK PubMed Central (United Kingdom)

Breath analysis is a powerful noninvasive technique for the diagnosis and monitoring of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). Nitric oxide...Full Text Available

International Nuclear Information System (INIS)

We consider the integrable structure of the quantum lattice W_N algebras. We introduce the ultralocal Lax matrix, and show that the Yang-Baxter relation is satisfied with a Z_N invariant R-matrix. (orig.).

International Nuclear Information System (INIS)

Systematic ensemble photoluminescence studies have been performed on type-I InP-quantum dots in Al_0_._2_0Ga_0_._8_0InP barriers, emitting at approximately 1.85 eV at 5 K. The influence of different barrier configurations as well as the incorporation of additional tunnel barriers on the optical properties has been investigated. The confinement energy between the dot barrier and the surrounding barrier layers, which is the sum of the band discontinuities for the valence and the conduction bands, was chosen to be approximately 190 meV by using Al_0_._5_0Ga_0_._5_0InP. In combination with 2 nm thick AlInP tunnel barriers, the internal quantum efficiency of these barrier configurations can be increased by up to a factor of 20 at elevated temperatures with respect to quantum dots without such layers. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)