Effective count rates for PET scanners with reduced and extended axial field of view.

We investigated the relationship between noise equivalent count (NEC) and axial field of view (AFOV) for PET scanners with AFOVs ranging from one-half to twice those of current clinical scanners. PET scanners with longer or shorter AFOVs could fulfill different clinical needs depending on exam volumes and site economics. Using previously validated Monte Carlo simulations, we modeled true, scattered and random coincidence counting rates for a PET ring diameter of 88 cm with 2, 4, 6, and 8 rings of detector blocks (AFOV 7.

Crystal structures of Burkholderia cenocepacia dihydropteroate synthase in the apo-form and complexed with the product 7,8-dihydropteroate.

Background: The enzyme dihydropteroate synthase (DHPS) participates in the de novo synthesis of folate cofactors by catalyzing the formation of 7,8-dihydropteroate from condensation of p-aminobenzoic acid with 6-hydroxymethyl-7,8-dihydropteroate pyrophosphate. DHPS is absent from humans, who acquire folates from diet, and has been validated as an antimicrobial therapeutic target by chemical and genetic means. The bacterium Burkholderia cenocepacia is an opportunistic pathogen and an infective agent of cystic fibrosis patients.

Suppressor of cytokine signaling-3 and intimal hyperplasia in porcine coronary arteries following coronary intervention.

Aims: The growth and differentiation of cells is regulated by cytokines by binding to cell-surface receptors and activating intracellular signal transduction cascade. Suppressor of cytokine signaling (SOCS)-3 is a negative regulator of cytokines. In this study we examined the expression of SOCS-3 in porcine coronary artery smooth muscle cells (PCASMCs) in vitro and in proliferating smooth muscle cells of neointimal lesions after coronary artery intervention in a swine model.

Effects of invertebrate iridescent virus 6 in Phyllophaga vandinei and its potential as a biocontrol delivery system.

Invertebrate iridescent virus 6 (IIV6) was determined to cause infection in Phyllophaga vandinei Smyth (Coleoptera: Scarabaeidae) through a range of modes of transmissions. This is the first evidence of IIV6 infection in P. vandinei that caused both patent and sub-lethal infections in larvae and adults.

Relationship between cervical vertebral maturation and mandibular growth.

Introduction: The cervical vertebrae have been proposed as a method of determining biologic maturity. The purposes of this study were to establish a pattern of mandibular growth and to relate this pattern to the stages of cervical vertebral maturation.

Methods: Cephalometric radiographs, taken annually from ages 9 to 18 years, were evaluated for 90 boys from the Burlington Growth Center, Toronto, Ontario, Canada.

Exploiting the high-resolution crystal structure of Staphylococcus aureus MenH to gain insight into enzyme activity.

Background: MenH (2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase) is a key enzyme in the biosynthesis of menaquinone, catalyzing an unusual 2,5-elimination of pyruvate from 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexadiene-1-carboxylate.

Results: The crystal structure of Staphylococcus aureus MenH has been determined at 2 Å resolution. In the absence of a complex to inform on aspects of specificity a model of the enzyme-substrate complex has been used in conjunction with previously published kinetic analyses, site-directed mutagenesis studies and comparisons with orthologues to investigate the structure and reactivity of MenH.

The role of Co²+ in the crystallization of human SENP1 and comments on the limitations of automated refinement protocols.

Metal ions often stabilize intermolecular contacts between macromolecules, thereby promoting crystallization. When interpreting a medium-resolution electron-density map of the catalytic domain of human sentrin-specific protease 1 (SENP1), a strong feature indicative of an ordered divalent cation was noted. This was assigned as Co(2+), an essential component of the crystallization mixture.

Impact of living arrangements and nationality on food habits and nutrient intakes in young adults.

The influence of living arrangements and nationality on nutrient intakes and food habits and beliefs were explored in young adults. Two hundred and thirty-two participants (20.4±2.

Studies on removing sulfachloropyridazine from groundwater with microbial bioreactors.

Sulfachloropyridazine (SCP), an antibiotic used in aquaculture and in animal husbandry, is a common contaminant in surface and groundwaters. Two types of microbial reactors were evaluated as methods for removing SCP from flowing water. One type of reactor evaluated was a nitrogen-limiting biobarrier; the other a slow-sand-filter.

Expression of leukemia/lymphoma related factor (LRF/Pokemon) in human benign prostate hyperplasia and prostate cancer.

Leukemia/lymphoma related factor (LRF), also known as Pokemon, is a protein that belongs to the POK family of transcriptional repressors. It has an oncogenic role in many different solid tumors. In this study, the expression of LRF was evaluated in benign prostate hyperplastic (BPH) and prostate cancer (PC) tissues.

Structure of recombinant Leishmania donovani pteridine reductase reveals a disordered active site.

Pteridine reductase (PTR1) is a potential target for drug development against parasitic Trypanosoma and Leishmania species, protozoa that are responsible for a range of serious diseases found in tropical and subtropical parts of the world. As part of a structure-based approach to inhibitor development, specifically targeting Leishmania species, well ordered crystals of L. donovani PTR1 were sought to support the characterization of complexes formed with inhibitors.

Large-scale field application of RNAi technology reducing Israeli acute paralysis virus disease in honey bees (Apis mellifera, Hymenoptera: Apidae).

The importance of honey bees to the world economy far surpasses their contribution in terms of honey production; they are responsible for up to 30% of the world's food production through pollination of crops. Since fall 2006, honey bees in the U.S.

Multiple-hit parameter estimation in monolithic detectors.

We examine a maximum-a-priori (MAP) method for estimating the primary interaction position of gamma rays with multiple-interaction sites (hits) in a monolithic detector. In assessing the performance of a multiple-hit estimator over that of a conventional one-hit estimator, we consider a few different detector and readout configurations of a 50-mm-wide square LSO block. For this study, we use simulated data from SCOUT, a Monte-Carlo tool for photon tracking and modeling scintillation-camera output.

Measurements of entrance-surface vs. conventional single-ended readout of a monolithic scintillator.

Availability of compact high-gain, low-noise Silicon Photomultipliers (SiPM) prompts us to examine readout sensors on the entrance surface (SES) as compared to the conventional single-ended readout with sensors on the opposing surface. We measured detector response statistics versus 3D position for these configurations using an 8×8 SiPM array on a 15-mm-thick by 32-mm-wide LYSO block. We calibrate an independently distributed multivariate-normal likelihood model and use it to generate maximum-likelihood estimates of 3D interaction position.

High-resolution structures of Trypanosoma brucei pteridine reductase ligand complexes inform on the placement of new molecular entities in the active site of a potential drug target.

Pteridine reductase (PTR1) is a potential target for drug development against parasitic Trypanosoma and Leishmania species. These protozoa cause serious diseases for which current therapies are inadequate. High-resolution structures have been determined, using data between 1.

Investigation of population heterogeneity of diet use among middle-aged Australians.

The purpose of the study was to determine patterns of diet use among middle-aged Australian men and women and the relationships between these different usage patterns and demographic characteristics, health status and health habits. A cross-sectional mail survey was conducted among a random sample of 2975 people aged 40-71 years in Victoria, Australia. A total of 1031 usable questionnaires were obtained which included information about the use of diets (e.

Enterobacter soli sp. nov.: a lignin-degrading γ-proteobacteria isolated from soil.

A Gram-negative bacterium that formed cream-colored colonies designated strain LF7 was isolated from soil collected in the Tambopata National Reserve in Madre de Dios, Peru. 16S rRNA sequence comparisons indicate that LF7 is a novel Enterobacter sp. closely related to E.

Crystal structures of penicillin-binding protein 3 from Pseudomonas aeruginosa: comparison of native and antibiotic-bound forms.

We report the first crystal structures of a penicillin-binding protein (PBP), PBP3, from Pseudomonas aeruginosa in native form and covalently linked to two important β-lactam antibiotics, carbenicillin and ceftazidime. Overall, the structures of apo and acyl complexes are very similar; however, variations in the orientation of the amino-terminal membrane-proximal domain relative to that of the carboxy-terminal transpeptidase domain indicate interdomain flexibility. Binding of either carbenicillin or ceftazidime to purified PBP3 increases the thermostability of the enzyme significantly and is associated with local conformational changes, which lead to a narrowing of the substrate-binding cleft.

Increased electrical output when a bacterial ABTS oxidizer is used in a microbial fuel cell.

Microbial fuel cells (MFCs) are a technology that provides electrical energy from the microbial oxidation of organic compounds. Most MFCs use oxygen as the oxidant in the cathode chamber. This study examined the formation in culture of an unidentified bacterial oxidant and investigated the performance of this oxidant in a two-chambered MFC with a proton exchange membrane and an uncoated carbon cathode.

Pseudomonas seleniipraecipitatus sp. nov.: a selenite reducing γ-proteobacteria isolated from soil.

A Gram-negative, yellow pigmented bacterium designated strain CA5(T) that reduced selenite to elemental red selenium was isolated from soil. 16S rRNA gene sequence alignment identified the isolate as a novel Pseudomonas species with P. argentinensis, P.

Crystal structure of Leishmania major ADP-ribosylation factor-like 1 and a classification of related GTPase family members in this Kinetoplastid.

ADP-ribosylation factor-like (ARL) proteins are small GTPases that undergo conformational changes upon nucleotide binding, and which regulate the affinity of ARLs for binding other proteins, lipids or membranes. There is a paucity of structural data on this family of proteins in the Kinetoplastida, despite studies implicating them in key events related to vesicular transport and regulation of microtubule-dependent processes. The crystal structure of Leishmania major ARL1 in complex with GDP has been determined to 2.

Baby boomers' food shopping habits. Relationships with demographics and personal values.

The purpose of this study was to examine baby boomers' food shopping behaviours and to investigate their relationships with demographics and personal values. A questionnaire concerning food shopping behaviours, personal values and demographics was mailed to a random sample of 2975 people aged 40-70 years in Victoria, Australia. Usable questionnaires of 1031 were obtained.

Parametric Design Study of a Long Axial Field-of-View PET Scanner using a Block-Detector Tomograph Simulation of a Cylindrical Phantom.

We are conducting a two-phase study, which aims to select design parameters of a long-axis positron emission tomography (PET) scanner that are a compromise between detection performance and cost. In this first phase, we examine the effects of axial length, detector thickness and collimator geometry on the noise equivalent count rate per axial length (λNEC) and noise equivalent count rate per slice (dNEC). We use these metrics as approximate, but quickly computed, indicators of a PET-scanner's performance at a detection task.

Biodegradation of pyrene in sand, silt and clay fractions of sediment.

Microbial degradation is the dominant pathway for natural attenuation of PAHs in environmental compartments such as sediments, which in turn depends on the bioavailability of PAHs. The bioavailability of PAHs has seldom been studied at the sediment particle size scale. We evaluated biodegradation of pyrene by Mycobacterium vanbaalenii PYR-1 as a function of sediment particle sizes, and investigated the relationship between the rate of degradation on sand, silt and clay particles with their individual desorption kinetics measured with the Tenax extraction method.

Structure of Staphylococcus aureus adenylosuccinate lyase (PurB) and assessment of its potential as a target for structure-based inhibitor discovery.

The medium-resolution structure of adenylosuccinate lyase (PurB) from the bacterial pathogen Staphylococcus aureus in complex with AMP is presented. Oxalate, which is likely to be an artifact of crystallization, has been modelled in the active site and occupies a position close to that where succinate is observed in orthologous structures. PurB catalyzes reactions that support the provision of purines and the control of AMP/fumarate levels.