Data driven surrogate signal extraction for dynamic PET using selective PCA: time windows versus the combination of components.

Respiratory motion correction is beneficial in positron emission tomography (PET), as it can reduce artefacts caused by motion and improve quantitative accuracy. Methods of motion correction are commonly based on a respiratory trace obtained through an external device (like the real time position management system) or a data driven method, such as those based on dimensionality reduction techniques (for instance principal component analysis (PCA)). PCA itself being a linear transformation to the axis of greatest variation.

The threshold of rule productivity in infants.

Most learning theories agree that the productivity of a rule or a pattern relies on regular exemplars being dominant over exceptions; the threshold for productivity is, however, unclear; moreover, gradient productivity levels are assumed for different rules/patterns, regular or irregular. One theory by Yang, the Tolerance Principle (TP), specified a productivity threshold applicable to all rules, calculated by the numbers of total exemplars and exceptions of a rule; furthermore, rules are viewed as quantal, either productive or unproductive, with no gradient levels. We evaluated the threshold and gradience-quantalness questions by investigating infants' generalization.

When language-general and language-specific processes are in conflict: The case of sub-syllabic word segmentation in toddlers.

Infants use statistics-based word segmentation strategies from the preverbal stage. Statistical segmentation is, however, constrained by the Onset Bias, a language-universal principle that disfavors segmentation that harms syllable integrity. Children eventually learn language-specific exceptions to this principle.

Consensus Recommendations on the Use of F-FDG PET/CT in Lung Disease.

PET with F-FDG has been increasingly applied, predominantly in the research setting, to study drug effects and pulmonary biology and to monitor disease progression and treatment outcomes in lung diseases that interfere with gas exchange through alterations of the pulmonary parenchyma, airways, or vasculature. To date, however, there are no widely accepted standard acquisition protocols or imaging data analysis methods for pulmonary F-FDG PET/CT in these diseases, resulting in disparate approaches. Hence, comparison of data across the literature is challenging.

Use of non-Gaussian time-of-flight kernels for image reconstruction of Monte Carlo simulated data of ultra-fast PET scanners.

Introduction: Time-of-flight (TOF) positron emission tomography (PET) scanners can provide significant benefits by improving the noise properties of reconstructed images. In order to achieve this, the timing response of the scanner needs to be modelled as part of the reconstruction process. This is currently achieved using Gaussian TOF kernels.

Effect of attenuation mismatches in time of flight PET reconstruction.

While the pursuit of better time resolution in positron emission tomography (PET) is rapidly evolving, little work has been performed on time of flight (TOF) image quality at high time resolution in the presence of modelling inconsistencies. This works focuses on the effect of using the wrong attenuation map in the system model, causing perturbations in the reconstructed radioactivity image. Previous work has usually considered the effects to be local to the area where there is attenuation mismatch, and has shown that the quantification errors in this area tend to reduce with improved time resolution.

PET image reconstruction using physical and mathematical modelling for time of flight PET-MR scanners in the STIR library.

This work demonstrates how computational and physical modelling of the positron emission tomography (PET) image acquisition process for a state-of-the-art integrated PET and magnetic resonance imaging (PET-MR) system can produce images comparable to the manufacturer. The GE SIGNA PET/MR scanner is manufactured by General Electric and has time-of-flight (TOF) capabilities of about 390 ps. All software development took place in the Software for Tomographic Image Reconstruction (STIR: http://stir.

Effect of positron range on PET quantification in diseased and normal lungs.

The impact of positron range on PET image reconstruction has often been investigated as a blurring effect that can be partly corrected by adding an element to the PET system matrix in the reconstruction, usually based on a Gaussian kernel constructed from the attenuation values. However, the physics involved in PET is more complex. In regions where density does not vary, positron range indeed involves mainly blurring.

Implementation and validation of time-of-flight PET image reconstruction module for listmode and sinogram projection data in the STIR library.

In this paper, we describe the implementation of support for time-of-flight (TOF) positron emission tomography (PET) for both listmode and sinogram data in the open source software for tomographic image reconstruction (STIR). We provide validation and performance characterization using simulated data from the open source GATE Monte Carlo toolbox, with TOF configurations spanning from 81.2 to 209.

Synthesis of a class of core-modified aza-BODIPY derivatives.

The convenient synthesis of a new class of conjugated aza-BODIPY derivatives from readily available precursors has been achieved. The new materials bear close structural similarity to BODIPYs but differ significantly in electronic configuration from known derivatives, leading to markedly different absorption and emission properties.

Meta-analysis of operative mortality and complications in patients from minority ethnic groups.

Background: Insight into the effects of ethnic disparities on patients' perioperative safety is necessary for the development of tailored improvement strategies. The aim of this study was to review the literature on safety differences between patients from minority ethnic groups and those from the ethnic majority undergoing surgery.

Methods: PubMed, CINAHL, the Cochrane Library and Embase were searched using predefined inclusion criteria for available studies from January 1990 to January 2013.

Heterologous Processing and Export of the Bacteriocins Pediocin PA-1 and Lactococcin A in Lactococcus Lactis: A Study with Leader Exchange.

The bacteriocins pediocin PA-1 and lactococcin A are synthesized as precursors carrying N-terminal extensions with a conserved cleavage site preceded by two glycine residues in positions -2 and -1. Each bacteriocin is translocated through the cytoplasmic membrane by an integral membrane protein of the ABC cassette superfamily which, in the case of pediocin PA-1, has been shown to possess peptidase activity responsible for proteolytic cleavage of the pre-bacteriocin. In each case, another integral membrane protein is essential for bacteriocin production.

Composite microparticles with in vivo reduction of the burst release effect.

The aim of this study was to develop microparticles containing nanoparticles (composite microparticles) for prolonged drug delivery with reduced burst effect in vitro and in vivo. Such composite microparticles were prepared with hydrophobic and biodegradable polymers [poly(epsilon-caprolactone), poly(lactic-co-glycolic) acid]. Ibuprofen was chosen as the model drug, and microparticles were prepared by the extraction technique with ethyl acetate as the solvent.

Increase in the vascular residence time of propranolol-loaded nanoparticles coated with heparin.

Propranolol-HCI incorporated nanoparticles prepared with a blend of a polyester and a polycationic polymer and coated or not with a low molecular weight heparin by electrostatic interactions were prepared by emulsification followed by solvent evaporation. The mean diameter was 388 and 357 nm for coated and uncoated nanoparticles, respectively, and the entrapment efficiency ranged from 20 to 32%. Coated nanoparticles were negatively-charged, whereas uncoated nanoparticles displayed a positive zeta potential (+30 mV).

Molecular characterization of three plasmids from Bifidobacterium longum.

The complete nucleotide sequences for pNAC1 (3538bp) from strain RW048 as well as for pNAC2 (3684bp) and pNAC3 (10,224bp) from strain RW041 of Bifidobacterium longum were determined. The largest ORF (repB) of pNAC1 encodes a putative protein similar to those involved in a rolling-circle (RC) replication mechanism, which was confirmed by demonstration of single-strand intermediates in the host cell. The putative RepB gene product of pNAC2 is most similar to the replication protein of pDOJH10L and pKJ36.

DNA sequence analysis of three Lactococcus lactis plasmids encoding phage resistance mechanisms.

The three Lactococcus lactis plasmids pSRQ700, pSRQ800, and pSRQ900 encode the previously described anti-phage resistance mechanisms LlaDCHI, AbiK, and AbiQ, respectively. Since these plasmids are likely to be introduced into industrial Lactococcus lactis strains used to manufacture commercial fermented dairy products, their complete DNA sequences were determined and analyzed. The plasmids pSRQ700 (7784 bp), pSRQ800 (7858 bp), and pSRQ900 (10,836 bp) showed a similar genetic organization including a common lactococcal theta-type replicon.

A coelectroporation method for the isolation of cryptic plasmids from Lactococcus lactis.

Aims: A coelectroporation method using a marker plasmid for indirect selection of lactococcal plasmids with unassigned functions was evaluated.

Methods And Results: Cryptic plasmids were mixed with an erythromycin resistance (Eryr) marker plasmid and introduced into a recipient strain by electroporation, followed by plasmid extraction of erythromycin-resistant transformants. By optimizing the ratio between the marker plasmid and the cryptic plasmids, an average of 20% cotransformants was obtained, including combinations of more than one cryptic plasmid.

Molecular characterization of a theta replication plasmid and its use for development of a two-component food-grade cloning system for Lactococcus lactis.

pCD4, a small, highly stable theta-replicating lactococcal plasmid, was used to develop a food-grade cloning system. Sequence analysis revealed five open reading frames and two putative cis-acting regions. None appears to code for undesirable phenotypes with regard to food applications.

Microbiological and molecular impacts of AbiK on the lytic cycle of Lactococcus lactis phages of the 936 and P335 species.

The lactococcal abortive infection mechanism AbiK was previously shown to be highly effective against the small isometric-headed bacteriophage ul36 of the P335 species, as evidenced by an efficiency of plaquing (e.o.p.

AbiQ, an abortive infection mechanism from Lactococcus lactis.

Lactococcus lactis W-37 is highly resistant to phage infection. The cryptic plasmids from this strain were coelectroporated, along with the shuttle vector pSA3, into the plasmid-free host L. lactis LM0230.

Phenotypic and genetic characterization of the bacteriophage abortive infection mechanism AbiK from Lactococcus lactis.

The natural plasmid pSRQ800 isolated from Lactococcus lactis subsp. lactis W1 conferred strong phage resistance against small isometric phages of the 936 and P335 species when introduced into phage-sensitive L. lactis strains.

Anti-DNA.RNA antibodies: an efficient tool for non-isotopic detection of Listeria species through a liquid-phase hybridization assay.

This study was undertaken to evaluate the potential of a new approach using anti-DNA.RNA monoclonal antibodies to detect Listeria in both pure culture and inoculated meat and meat products. A sensitive liquid-phase assay was first developed, based on the formation in solution of a hybrid between a 784-bp DNA probe, specific for the genus Listeria, and target rRNA.