Dynamics of Overhauser Field under nuclear spin diffusion in a quantum dot

The coherence of electron spin can be significantly enhanced by locking the Overhauser field from nuclear spins using the nuclear spin preparation. We propose a theoretical model to calculate the long time dynamics of the Overhauser field under intrinsic nuclear spin diffusion in a quantum dot. We obtain a simplified diffusion equation that can be numerically solved and show quantitatively how the Knight shift and the electron-mediated nuclear spin flip-flop affect the nuclear spin diffusion. The results explain several recent experimental observations, where the decay time of Overhauser field is measured under different configurations, including variation of the external magnetic field, the electron spin configuration in a double dot, and the initial nuclear spin polarization rate.Comment: 6 pages, 5 figure

Positron-electron autocorrelation function study of E-center in silicon

A study was conducted on the positron-electron autocorrelation function of defect center in silicon. The positron annihilation lifetime spectroscopy (PALS) spectra taken on the as-grown and defected samples of silicon were studied. It was found that the positron binding energy to the defect could be estimated from the ratio of the positron-electron autocorrelates for bulk crystal and defect trapped positron states.published_or_final_versio

Evidence for glutamate as a neuroglial transmitter within sensory ganglia

This study examines key elements of glutamatergic transmission within sensory ganglia of the rat. We show that the soma of primary sensory neurons release glutamate when depolarized. Using acute dissociated mixed neuronal/glia cultures of dorsal root ganglia (DRG) or trigeminal ganglia and a colorimetric assay, we show that when glutamate uptake by satellite glial cells (SGCs) is inhibited, KCl stimulation leads to simultaneous increase of glutamate in the culture medium. With calcium imaging we see that the soma of primary sensory neurons and SGCs respond to AMPA, NMDA, kainate and mGluR agonists, and selective antagonists block this response. Using whole cell patch-clamp technique, inward currents were recorded from small diameter (<30 µm) DRG neurons from intact DRGs (ex-vivo whole ganglion preparation) in response to local application of the above glutamate receptor agonists. Following a chronic constriction injury (CCI) of either the inferior orbital nerve or the sciatic nerve, glutamate expression increases in the trigeminal ganglia and DRG respectively. This increase occurs in neurons of all diameters and is present in the somata of neurons with injured axons as well as in somata of neighboring uninjured neurons. These data provides additional evidence that glutamate can be released within the sensory ganglion, and that the somata of primary sensory neurons as well as SGCs express functional glutamate receptors at their surface. These findings, together with our previous gene knockdown data, suggest that glutamatergic transmission within the ganglion could impact nociceptive thresholdpublished_or_final_versio

Pulmonary effects of inhalation of spark-generated silver nanoparticles in Brown-Norway and Sprague-Dawley rats

The increasing use of silver nanoparticles (AgNPs) in consumer products is concerning. We examined the potential toxic effects when inhaled in Brown-Norway (BN) rats with a pre-inflammatory state compared to Sprague-Dawley (SD) rats.We determined the effect of AgNPs generated from a spark generator (mass concentration: 600-800 μg/mm(3); mean diameter: 13-16 nm; total lung doses: 8 [Low] and 26-28 [High] μg) inhaled by the nasal route in both rat strains. Rats were sacrificed at day 1 and day 7 after exposure and measurement of lung function.In both strains, there was an increase in neutrophils in bronchoalveolar lavage (BAL) fluid at 24 h at the high dose, with concomitant eosinophilia in BN rats. While BAL inflammatory cells were mostly normalised by Day 7, lung inflammation scores remained increased although not the tissue eosinophil scores. Total protein levels were elevated at both lung doses in both strains. There was an increase in BAL IL-1β, KC, IL-17, CCL2 and CCL3 levels in both strains at Day 1, mostly at high dose. Phospholipid levels were increased at the high dose in SD rats at Day 1 and 7, while in BN rats, this was only seen at Day 1; surfactant protein D levels decreased at day 7 at the high dose in SD rats, but was increased at Day 1 at the low dose in BN rats. There was a transient increase in central airway resistance and in tissue elastance in BN rats at Day 1 but not in SD rats. Positive silver-staining was seen particularly in lung tissue macrophages in a dose and time-dependent response in both strains, maximal by day 7. Lung silver levels were relatively higher in BN rat and present at day 7 in both strains.Presence of cellular inflammation and increasing silver-positive macrophages in lungs at day 7, associated with significant levels of lung silver indicate that lung toxicity is persistent even with the absence of airway luminal inflammation at that time-point. The higher levels and persistence of lung silver in BN rats may be due to the pre-existing inflammatory state of the lungs

Lung Injury Prevention with Aspirin (LIPS-A): a Protocol for a Multicentre Randomised Clinical Trial in Medical Patients at High Risk of Acute Lung Injury

Introduction: Acute lung injury (ALI) is a devastating condition that places a heavy burden on public health resources. Although the need for effective ALI prevention strategies is increasingly recognised, no effective preventative strategies exist. The Lung Injury Prevention Study with Aspirin (LIPS-A) aims to test whether aspirin (ASA) could prevent and/or mitigate the development of ALI. Methods and analysis LIPS-A is a multicentre, double-blind, randomised clinical trial testing the hypothesis that the early administration of ASA will result in a reduced incidence of ALI in adult patients at high risk. This investigation will enrol 400 study participants from 14 hospitals across the USA. Conditional logistic regression will be used to test the primary hypothesis that early ASA administration will decrease the incidence of ALI. Ethics and dissemination Safety oversight will be under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained from the DSMB prior to enrolling the first study participant. Approval of both the protocol and informed consent documents were also obtained from the institutional review board of each participating institution prior to enrolling study participants at the respective site. In addition to providing important clinical and mechanistic information, this investigation will inform the scientific merit and feasibility of a phase III trial on ASA as an ALI prevention agent. The findings of this investigation, as well as associated ancillary studies, will be disseminated in the form of oral and abstract presentations at major national and international medical specialty meetings. The primary objective and other significant findings will also be presented in manuscript form. All final, published manuscripts resulting from this protocol will be submitted to Pub Med Central in accordance with the National Institute of Health Public Access Policy

Comparison theory and smooth minimal C*-dynamics

We prove that the C*-algebra of a minimal diffeomorphism satisfies Blackadar's Fundamental Comparability Property for positive elements. This leads to the classification, in terms of K-theory and traces, of the isomorphism classes of countably generated Hilbert modules over such algebras, and to a similar classification for the closures of unitary orbits of self-adjoint elements. We also obtain a structure theorem for the Cuntz semigroup in this setting, and prove a conjecture of Blackadar and Handelman: the lower semicontinuous dimension functions are weakly dense in the space of all dimension functions. These results continue to hold in the broader setting of unital simple ASH algebras with slow dimension growth and stable rank one. Our main tool is a sharp bound on the radius of comparison of a recursive subhomogeneous C*-algebra. This is also used to construct uncountably many non-Morita-equivalent simple separable amenable C*-algebras with the same K-theory and tracial state space, providing a C*-algebraic analogue of McDuff's uncountable family of II_1 factors. We prove in passing that the range of the radius of comparison is exhausted by simple C*-algebras.Comment: 30 pages, no figure

How strong is the evidence for accelerated expansion?

We test the present expansion of the universe using supernova type Ia data without making any assumptions about the matter and energy content of the universe or about the parameterization of the deceleration parameter. We assume the cosmological principle to apply in a strict sense. The result strongly depends on the data set, the light-curve fitting method and the calibration of the absolute magnitude used for the test, indicating strong systematic errors. Nevertheless, in a spatially flat universe there is at least a 5 sigma evidence for acceleration which drops to 1.8 sigma in an open universe.Comment: 16 pages, 3 figure

A New Constructive Heuristic for the Fm|block|ST

This paper deals with the blocking flow shop problem and proposes new constructive procedures for the total tardiness minimization of jobs. The heuristic has three-phases to build the sequence; the first phase selects the first job to be scheduled, the second phase arranges the remaining jobs and the third phase uses the insertion procedure of NEH to improve the sequence. The proposed procedures evaluate the tardiness associated to the sequence obtained before and after the third phase in order to keep the best of both because the insertion phase can worsen the result. The computational evaluation of these procedures against the benchmark constructive procedures from the literature reveals their good performance.Postprint (published version

Inflation and dark matter in two Higgs doublet models

We consider the Higgs inflation in the extension of the Standard Model with two Higgs doublets coupled to gravity non-minimally. In the presence of an approximate global U(1) symmetry in the Higgs sector, both radial and angular modes of neutral Higgs bosons drive inflation where large non-Gaussianity is possible from appropriate initial conditions on the angular mode. We also discuss the case with single-field inflation for which the U(1) symmetry is broken to a Z_2 subgroup. We show that inflationary constraints, perturbativity and stability conditions restrict the parameter space of the Higgs quartic couplings at low energy in both multi- and single-field cases. Focusing on the inert doublet models where Z_2 symmetry remains unbroken at low energy, we show that the extra neutral Higgs boson can be a dark matter candidate consistent with the inflationary constraints. The doublet dark matter is always heavy in multi-field inflation while it can be light due to the suppression of the co-annihilation in single-field inflation. The implication of the extra quartic couplings on the vacuum stability bound is also discussed in the light of the recent LHC limits on the Higgs mass.Comment: (v1) 28 pages, 8 figures; (v2) 29 pages, a new subsection 3.3 added, references added and typos corrected, to appear in Journal of High Energy Physic

Recurrent Upper Quadrant Pain: A Fish Bone Secondary to Gastric Perforation and Liver Abscess

A 60-year-old male patient was admitted to our hospital for recurrent upper quadrant pain for 1 month. He had a past history of coronary artery disease. After admission, he repeatedly suffered from high-grade fever, chills and upper quadrant pain. Computed tomography (CT) showed a round hypodense mass in the left lobe of the liver, approximately 2.7 × 2.2 cm in size, and a fish bone was confirmed by surgery in the left lobe of liver. The patient was cured completely after surgical removal of the fish bone and liver abscess. CT scan 1 month after discharge showed that the liver abscess had disappeared completely