807 research outputs found
A Single Laser System for Ground-State Cooling of 25-Mg+
We present a single solid-state laser system to cool, coherently manipulate
and detect Mg ions. Coherent manipulation is accomplished by
coupling two hyperfine ground state levels using a pair of far-detuned Raman
laser beams. Resonant light for Doppler cooling and detection is derived from
the same laser source by means of an electro-optic modulator, generating a
sideband which is resonant with the atomic transition. We demonstrate
ground-state cooling of one of the vibrational modes of the ion in the trap
using resolved-sideband cooling. The cooling performance is studied and
discussed by observing the temporal evolution of Raman-stimulated sideband
transitions. The setup is a major simplification over existing state-of-the-art
systems, typically involving up to three separate laser sources
Out-of-Equilibrium Admittance of Single Electron Box Under Strong Coulomb Blockade
We study admittance and energy dissipation in an out-of-equlibrium single
electron box. The system consists of a small metallic island coupled to a
massive reservoir via single tunneling junction. The potential of electrons in
the island is controlled by an additional gate electrode. The energy
dissipation is caused by an AC gate voltage. The case of a strong Coulomb
blockade is considered. We focus on the regime when electron coherence can be
neglected but quantum fluctuations of charge are strong due to Coulomb
interaction. We obtain the admittance under the specified conditions. It turns
out that the energy dissipation rate can be expressed via charge relaxation
resistance and renormalized gate capacitance even out of equilibrium. We
suggest the admittance as a tool for a measurement of the bosonic distribution
corresponding collective excitations in the system
Stabilizing entanglement autonomously between two superconducting qubits
Quantum error-correction codes would protect an arbitrary state of a
multi-qubit register against decoherence-induced errors, but their
implementation is an outstanding challenge for the development of large-scale
quantum computers. A first step is to stabilize a non-equilibrium state of a
simple quantum system such as a qubit or a cavity mode in the presence of
decoherence. Several groups have recently accomplished this goal using
measurement-based feedback schemes. A next step is to prepare and stabilize a
state of a composite system. Here we demonstrate the stabilization of an
entangled Bell state of a quantum register of two superconducting qubits for an
arbitrary time. Our result is achieved by an autonomous feedback scheme which
combines continuous drives along with a specifically engineered coupling
between the two-qubit register and a dissipative reservoir. Similar autonomous
feedback techniques have recently been used for qubit reset and the
stabilization of a single qubit state, as well as for creating and stabilizing
states of multipartite quantum systems. Unlike conventional, measurement-based
schemes, an autonomous approach counter-intuitively uses engineered dissipation
to fight decoherence, obviating the need for a complicated external feedback
loop to correct errors, simplifying implementation. Instead the feedback loop
is built into the Hamiltonian such that the steady state of the system in the
presence of drives and dissipation is a Bell state, an essential building-block
state for quantum information processing. Such autonomous schemes, broadly
applicable to a variety of physical systems as demonstrated by a concurrent
publication with trapped ion qubits, will be an essential tool for the
implementation of quantum-error correction.Comment: 39 pages, 7 figure
Are language production problems apparent in adults who no longer meet diagnostic criteria for attention-deficit/hyperactivity disorder?
In this study, we examined sentence production in a sample of adults (N = 21) who had had attention-deficit/hyperactivity disorder (ADHD) as children, but as adults no longer met DSM-IV diagnostic criteria (APA, 2000). This “remitted” group was assessed on a sentence production task. On each trial, participants saw two objects and a verb. Their task was to construct a sentence using the objects as arguments of the verb. Results showed more ungrammatical and disfluent utterances with one particular type of verb (i.e., participle). In a second set of analyses, we compared the remitted group to both control participants and a “persistent” group, who had ADHD as children and as adults. Results showed that remitters were more likely to produce ungrammatical utterances and to make repair disfluencies compared to controls, and they patterned more similarly to ADHD participants. Conclusions focus on language output in remitted ADHD, and the role of executive functions in language production
Genome Wide Transcriptome Analysis of Dendritic Cells Identifies Genes with Altered Expression in Psoriasis
Activation of dendritic cells by different pathogens induces the secretion of proinflammatory mediators resulting in
local inflammation. Importantly, innate immunity must be properly controlled, as its continuous activation leads to the
development of chronic inflammatory diseases such as psoriasis. Lipopolysaccharide (LPS) or peptidoglycan (PGN)
induced tolerance, a phenomenon of transient unresponsiveness of cells to repeated or prolonged stimulation,
proved valuable model for the study of chronic inflammation. Thus, the aim of this study was the identification of the
transcriptional diversity of primary human immature dendritic cells (iDCs) upon PGN induced tolerance. Using SAGESeq
approach, a tag-based transcriptome sequencing method, we investigated gene expression changes of primary
human iDCs upon stimulation or restimulation with Staphylococcus aureus derived PGN, a widely used TLR2 ligand.
Based on the expression pattern of the altered genes, we identified non-tolerizeable and tolerizeable genes. Gene
Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (Kegg) analysis showed marked enrichment of
immune-, cell cycle- and apoptosis related genes. In parallel to the marked induction of proinflammatory mediators,
negative feedback regulators of innate immunity, such as TNFAIP3, TNFAIP8, Tyro3 and Mer are markedly
downregulated in tolerant cells. We also demonstrate, that the expression pattern of TNFAIP3 and TNFAIP8 is
altered in both lesional, and non-lesional skin of psoriatic patients. Finally, we show that pretreatment of immature
dendritic cells with anti-TNF-α inhibits the expression of IL-6 and CCL1 in tolerant iDCs and partially releases the
suppression of TNFAIP8. Our findings suggest that after PGN stimulation/restimulation the host cell utilizes different
mechanisms in order to maintain critical balance between inflammation and tolerance. Importantly, the transcriptome
sequencing of stimulated/restimulated iDCs identified numerous genes with altered expression to date not associated
with role in chronic inflammation, underlying the relevance of our in vitro model for further characterization of IFNprimed
iDCs
Health-Promoting and Health-Risk Behaviors: Theory-Driven Analyses of Multiple Health Behavior Change in Three International Samples
Background: Co-occurrence of different behaviors was investigated using the theoretical underpinnings of the Transtheoretical Model, the Theory of Triadic Influence and the concept of Transfer.
Purpose: To investigate relationships between different health behaviors' stages of change, how behaviors group, and whether study participants cluster in terms of their behaviors.
Method: Relationships across stages for different behaviors were assessed in three studies with N = 3,519, 965, and 310 individuals from the USA and Germany by telephone and internet surveys using correlational analyses, factor analyses, and cluster analyses.
Results: Consistently stronger correlations were found between nutrition and physical activity (r = 0.16-0.26, p < 0.01) than between non-smoking and nutrition (r = 0.08-0.16, p < 0.03), or non-smoking and physical activity (r = 0.01-0.21). Principal component analyses of investigated behaviors indicated two factors: a "health-promoting" factor and a "health-risk" factor. Three distinct behavioral patterns were found in the cluster analyses.
Conclusion: Our results support the assumption that individuals who are in a higher stage for one behavior are more likely to be in a higher stage for another behavior as well. If the aim is to improve a healthy lifestyle, success in one behavior can be used to facilitate changes in other behaviors--especially if the two behaviors are both health-promoting or health-risky. Moreover, interventions should be targeted towards the different behavioral patterns rather than to single behaviors. This might be achieved by addressing transfer between behaviors
BubR1 as a prognostic marker for recurrence-free survival rates in epithelial ovarian cancers
BACKGROUND: Epithelial ovarian cancer is one of the most lethal malignancies, and has a high recurrence rate. Thus, prognostic markers
for recurrence are crucial for the care of ovarian cancer. As ovarian cancers frequently exhibit chromosome instability, we aimed at
assessing the prognostic significance of two key mitotic kinases, BubR1 and Aurora A.
METHODS: We analysed paraffin-embedded tissue sections from 160 ovarian cancer patients whose clinical outcomes had been
tracked after first-line treatment.
RESULTS: The median recurrence-free survival in patients with a positive and negative expression of BubR1 was 27 and 83 months,
respectively (Po0.001). A positive BubR1 expression was also associated with advanced stage, serous histology and high grade.
In contrast, Aurora A immunostaining did not correlate with any of the clinical parameters analysed.
CONCLUSION: BubR1, but not Aurora A, is a prognostic marker for recurrence-free survival rates in epithelial ovarian cancers.Research in the H Lee laboratory is funded by the National
Research Laboratory Program from the Korean ministry of
Education and Science (ROA-2008-000-20023-0). This work was
also supported by the Seoul National University Hospital Grant
(0420080450), the 21C Frontier Functional Genome Project (FG06-
2-14) of the Korean ministry of Education and Science, Korea
Research Foundation (KRF-2005-C00097), and the National R&D
Program for Cancer Control (0620070) from the Korean ministry
of Health welfare and Family Affairs. Imaging facilities in the H Lee
laboratory are funded by RCFC (R11-2005-009-04003-0) of the SRC
program from KOSEF
From START to FINISH : the influence of osmotic stress on the cell cycle
Peer reviewedPublisher PD
Which executive functioning deficits are associated with AD/HD, ODD/CD and comorbid AD/HD+ODD/CD?
Item does not contain fulltextThis study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3)~whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99~children ages 6–12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).17 p
STK295900, a Dual Inhibitor of Topoisomerase 1 and 2, Induces G<inf>2</inf> Arrest in the Absence of DNA Damage
STK295900, a small synthetic molecule belonging to a class of symmetric bibenzimidazoles, exhibits antiproliferative activity against various human cancer cell lines from different origins. Examining the effect of STK295900 in HeLa cells indicates that it induces G2 phase arrest without invoking DNA damage. Further analysis shows that STK295900 inhibits DNA relaxation that is mediated by topoisomerase 1 (Top 1) and topoisomerase 2 (Top 2) in vitro. In addition, STK295900 also exhibits protective effect against DNA damage induced by camptothecin. However, STK295900 does not affect etoposide-induced DNA damage. Moreover, STK295900 preferentially exerts cytotoxic effect on cancer cell lines while camptothecin, etoposide, and Hoechst 33342 affected both cancer and normal cells. Therefore, STK295900 has a potential to be developed as an anticancer chemotherapeutic agent. © 2013 Kim et al
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