bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facile synthesis of monodisperse ZnS capped CdS nanocrystals exhibiting efficient blue emission
Authors: Protière Myriam , Reiss Peter 
Published: July 2006

Abstract
A new method for the capping of colloidal CdS nanocrystals with ZnS shells is presented. A combination of the monomolecular precursor zinc ethylxanthate (Zn(ex)2) and zinc stearate was used to replace hazardous organometallic reagents usually applied in this procedure, i.e. bis(trimethylsilyl) sulfide and diethylzinc. Its simple preparation, air-stability and low decomposition temperature of 150 °C make Zn(ex)2a very suitable source for the ZnS shell growth. With this precursor, highly luminescent CdS/ZnS core/shell nanocrystals (Q.Y. 35–45%), exhibiting narrow emission linewidths of 15–18 nm (FWHM) in the blue spectral region, can reproducibly be obtained.
Can parathyroidectomy for primary hyperparathyroidism be carried out as a day-case procedure?
Authors: Carr E R M , Contractor K , Remedios D , Burke M 
Published: July 2006

Introduction: Surgery for primary hyperparathyroidism has traditionally involved a bilateral neck exploration performed as an in-patient procedure. We present a feasibility study to demonstrate whether, with a focused surgical exploration, the procedure can be carried out as a day case.Method: Eighty-seven patients had pre-operative sestamibi and ultrasound scans of the neck. When the results of these scans agreed, a unilateral neck exploration was carried out.Results: Sixty-seven patients received a focused approach parathyroidectomy. Ninety-seven per cent of these patients were normocalcaemic after the first operation. All patients who fitted the day-case criteria left hospital the following morning.Discussion: When pre-operative imaging results agree, a parathyroidectomy can be carried out using a unilateral neck exploration, avoiding the increased risks associated with a bilateral exploration.Conclusion: Parathyroidectomy can be safely carried out as a day-case procedure in selected patients.
A two-dimensional analysis of mode conversion at a resonance layer with high-magnetic field side reflection
Authors: NASSIRI-MOFAKHAM NORA , PARVAZIAN AKBAR 
Published: July 2006

AbstractMode converted Bernstein waves potentially allow the implementation of local heating and current drive in spherical torus devices, which are not directly accessible to low-harmonic cyclotron waves. The mode conversion method of Cairns and Lashmore-Davies previously used to study the usual mode conversion in non-planar geometry is extended to include the effect of the high-magnetic-field-side cutoff, and is solved analytically. The analytic solutions to the triplet, cutoff–resonance–cutoff, equations give the reflection and conversion coefficients in terms of parameters defining the local behavior of the dispersion relation. The variation of mode conversion efficiency depends not only on the coupling parameter but also on the phasing effect introduced by the high-field-side cutoff. The change in characteristic phases, which are concerned with the coupling parameter, brings an additional degree of freedom allowing optimization via the position of the high-field cutoff. A discrete spectrum of phases exists for which complete mode conversion of the incident wave for a transit of the resonance region can be achieved. The results we obtain here give the general conditions for efficient Bernstein wave heating in two-dimensional geometry.
Meiotic recombination hotspots in plants
Authors: Mézard C. 
Published: July 2006

Many studies have demonstrated that the distribution of meiotic crossover events along chromosomes is non-random in plants and other species with sexual reproduction. Large differences in recombination frequencies appear at several scales. On a large scale, regions of high and low rates of crossover have been found to alternate along the chromosomes in all plant species studied. High crossover rates have been reported to be correlated with several chromosome features (e.g. gene density and distance to the centromeres). However, most of these correlations cannot be extended to all plant species. Only a few plant species have been studied on a finer scale. Hotspots of meiotic recombination (i.e. DNA fragments of a few kilobases in length with a higher rate of recombination than the surrounding DNA) have been identified in maize and rice. Most of these hotspots are intragenic. In Arabidopsis thaliana, we have identified several DNA fragments (less than 5 kb in size) with genetic recombination rates at least 5 times higher than the whole-chromosome average [4.6 cM (centimorgan)/Mb], which are therefore probable hotspots for meiotic recombination. Most crossover breakpoints lie in intergenic or non-coding regions. Major efforts should be devoted to characterizing meiotic recombination at the molecular level, which should help to clarify the role of this process in genome evolution.
Analysis of a cross between green and red fluorescent trypanosomes
Authors: Gibson W. , Peacock L. , Ferris V. , Williams K. , Bailey M. 
Published: July 2006

Trypanosoma brucei undergoes genetic exchange in its insect vector, but the mechanism is unknown and no one has yet seen the process. By crossing genetically engineered red and green fluorescent trypanosomes, we have been able to pinpoint the location of genetic exchange in the fly and search for intermediate stages. In experimental crosses of red and green parental trypanosomes, yellow hybrid trypanosomes first appeared in the fly salivary glands as early as 13 days after infection and were observed only in flies with a mixture of red and green trypanosomes in one or both salivary glands. Despite high numbers of flies with mixed infections, yellow trypanosomes were not detected in the fly midgut or proventriculus. The hybrid nature of yellow trypanosomes was confirmed by analysis of molecular karyotypes and microsatellite alleles. As well as yellow hybrids, hybrid trypanosomes with red, green or no fluorescence were also recovered from fly salivary glands. Analysis of microsatellite alleles in parental and progeny clones showed Mendelian inheritance. Our findings are consistent with the hypothesis that mating takes place between trypanosomes in the salivary glands of the fly before they attach to the salivary gland epithelium.
Automated Editing of Radio Interferometer Data with PIEFLAG
Authors: Middelberg Enno 
Published: July 2006

AbstractEditing radio interferometer data, a process commonly known as ‘flagging’, can be laborious and time-consuming. One quickly tends to flag more data than actually required, sacrificing sensitivity and image fidelity in the process. I describe a program, PIEFLAG, which can analyze radio interferometer data to filter out measurements which are likely to be affected by interference. PIEFLAG uses two algorithms to allow for data sets which are either dominated by receiver noise or by source structure. Together, the algorithms detect essentially all affected data whilst the amount of data which is not affected by interference but falsely marked as such is kept to a minimum. The sections marked by PIEFLAG are very similar to what would be deemed affected by the observer in a visual inspection of the data. PIEFLAG displays its results concisely and allows the user to add and remove flags interactively. It is written in python, is easy to install and use, and has a variety of options to adjust its algorithms to a particular observing situation. I describe how PIEFLAG works and illustrate its effect using data from typical observations.
The putative monomeric G‐protein GBP1 is negatively associated with fumonisin B1 production in Fusarium verticillioides
Authors: SAGARAM UMA SHANKAR , BUTCHKO ROBERT A. E. , SHIM WON‐BO 
Published: July 2006

SUMMARYFumonisin B1 (FB1) is a mycotoxin produced by Fusarium verticillioides that contaminates maize. FB1 has been linked to a number of human and animal mycotoxicoses worldwide. Despite its significance, our understanding of the FB1 biosynthesis regulatory mechanisms is limited. Here, we describe F. verticillioides GBP1, encoding a monomeric G‐protein, and its role in FB1 biosynthesis. GBP1 was discovered as an expressed sequence tag (EST) up‐regulated in the F. verticillioides fcc1 mutant that showed reduced conidiation and no FB1 biosynthesis when grown on maize kernels. Sequence analysis showed that GBP1 encodes a putative 368‐amino‐acid protein with similarity to DRG and Obg subclasses of G‐proteins that are involved in development and stress responses. A GBP1 knockout mutant (Δgbp1) exhibited normal growth, but increased FB1 production (> 58%) compared with the wild‐type when grown on corn kernels. Complementation of Δgbp1 with the wild‐type GBP1 gene restored FB1 production levels to that of the wild‐type. Our data indicate that GBP1 is negatively associated with FB1 biosynthesis but not with conidiation in F. verticillioides. The deletion of GBP1 led to up‐regulation of key FB1 biosynthetic genes, FUM1 and FUM8, suggesting that the increased FB1 production in Δgbp1 is due to over‐expression of FUM genes.
Laser capture microdissection: a novel approach to microanalysis of plant–microbe interactions
Authors: RAMSAY KERRY , JONES MICHAEL G. K. , WANG ZHAOHUI 
Published: July 2006

SUMMARYGene expression studies are often carried out at the whole organism, organ or tissue levels. The different cell types present in most tissue exhibit different patterns of gene expression. This limits analyses because results obtained represent an average of the activities of the different cell types, and may lead to masking of genes of interest that are specifically expressed in a particular cell type. The recent development of laser capture microdissection (LCM) now enables target cells to be isolated from complex tissues and allows analysis of specific cell types that represent the in vivo state at the time of sample extraction. LCM has been applied to analyse plant tissues in a number of studies. This review illustrates the application of LCM in studies on gene expression profiling and proteomics, and also in research on plant–microbe interactions.
Spatial variation in demography and population growth rate: the importance of natal location
Authors: REID J. M. , BIGNAL E. M. , BIGNAL S. , McCRACKEN D. I. , MONAGHAN P. 
Published: July 2006

SummaryUnderstanding the pattern and magnitude of spatial variation in demography and population growth rate (λ) is key to understanding the structure and dynamics of natural populations. However, such spatial variation is challenging to quantify. We use > 20 years of individual life‐history data to quantify small‐ and large‐scale spatial variation in demography and λ within a single population of red‐billed choughsPyrrhocorax pyrrhocoraxon Islay, Scotland. Critically, we demonstrate a major importance of an individual's natal rather than current location in driving observed spatial variation.Breeding success (the number of offspring fledged per breeding attempt) varied among individual chough nest sites but did not vary on a larger spatial scale across Islay.The proportion of fledglings observed to survive to recruiting age varied markedly among individual nest sites and also varied more widely across Islay. Spatial capture–mark–recapture models defined two discrete geographical regions where fledgling survival differed significantly: choughs fledged in region ‘BGE’ were more likely to survive than choughs fledged in region ‘CNSW’ as both subadults and adults.The asymptotic λ attributable to breeding attempts in region BGE exceeded unity, and exceeded that attributable to breeding attempts in region CNSW. Relatively productive and unproductive regions therefore exist within this population.Spatial variation in adult survival was better explained by an individual's natal region than the region where that individual settled to breed. Spatial variation in λ would consequently have remained undetected had survival been measured across resident breeders rather than across individuals fledged in each region. Furthermore, breeding success was a weak predictor of a nest site's estimated productivity of recruits.We therefore describe marked spatial variation in demography and λ within a single population of a territorial vertebrate, mediated partly by long‐term links between an individual's natal location and its subsequent life‐history. Life‐long monitoring of individuals of known origin may therefore be necessary to identify accurately subpopulations of intrinsically high and low λ.
Comparative phylogeography of coastal limpets across a marine disjunction in New Zealand
Authors: GOLDSTIEN SHARYN J. , SCHIEL DAVID R. , GEMMELL NEIL J. 
Published: July 2006

AbstractCook Strait, which separates the North and South Island of New Zealand, has been a transient, but re‐occurring feature of the New Zealand land mass throughout the Pleistocene, maintaining its current width and depth for the past 5000 years. Historic land fragmentation coupled with the complex hydrography of the Greater Cook Strait region has created both biogeographic and phylogeographic disjunctions between the North and South Island in several marine species. Here we use mitochondrial cytochromebDNA sequences of three endemic intertidal limpets,Cellana ornata,Cellana radiansandCellana flavato assess intraspecific phylogeographic patterns across Cook Strait and to look for interspecific concordance of ecological and evolutionary processes among closely related taxa. We sequenced 328–359 bp in 85–321 individuals from 8–31 populations spanning the biogeographic range of the three species. Intraspecific phylogeographic analyses show moderate to strong genetic discontinuity among North and South Island populations due to allopatric fragmentation. This pattern was broadly concordant across the three species and the observed divergence among this group of intertidal limpets (0.3–2.0%) is similar to that of previously studied subtidal organisms. For each species, divergence time calculations suggest contemporary North and South Island lineages diverged from their respective most recent common ancestor approximately 200 000 to 300 000 years before present (bp), significantly earlier than previous estimates in other coastal marine taxa that arose from a miscalculation of divergence time.
Elevated body mass index and mortality risk in the elderly
Authors: Janssen I. , Mark A. E. 
Published: July 2006

SummaryThe purpose of this report was to perform a systematic review and meta‐analysis of the studies examining the impact of an elevated body mass index (BMI) on mortality risk in elderly (≥65 years) men and women. A variance‐based method of meta‐analysis was used to summarize the relationships from available studies. The summary relative risk of all‐cause mortality from the 26 analyses that included a risk estimate for a BMI within the overweight range was 1.00 (95% confidence intervals, 0.97–1.03). The summary relative risk of all‐cause mortality for the 28 analyses that included a risk estimate for a BMI within the obese range was 1.10 (1.06–1.13). These calculations indicate that a BMI in the overweight range is not associated with a significantly increased risk of mortality in the elderly, while a BMI in the moderately obese range is only associated with a modest increase in mortality risk.
Obesity and the heart: redefinition of the relationship
Authors: Iacobellis G. , Sharma A. M. 
Published: July 2006

SummaryAlthough obesity is an important cardiovascular risk factor, growing evidence shows that obesity is not always related to an unfavourable cardio‐metabolic profile or poor cardiac outcomes. Recent studies show that excess fat even in the absence of comorbidities (uncomplicated obesity) can lead to adaptive cardiac morphological and functional changes. Uncomplicated obesity represents a well‐defined clinical entity that should be carefully considered and followed up. The existence of metabolically healthy subjects presenting a lower prevalence of cardiac modifications and risk factors strongly suggests that a redefinition of obesity based on regional fat distribution indices like waist‐to‐hip ratio instead of body mass index is warranted.
The impact of highly active antiretroviral therapy on the incidence and outcomes of AIDS‐defining cancers in Southern Alberta
Authors: Gingues S , Gill MJ 
Published: July 2006

ObjectivesTo determine the impact of highly active antiretroviral therapy (HAART) on the incidence and outcomes of Kaposi's sarcoma (KS), non‐Hodgkin's lymphoma (NHL) and invasive cervical cancer/dysplasia in a well‐defined geographical HIV‐infected population between 1984 and 2005.MethodsA clinic database search, chart review and verification with public health records were undertaken for all AIDS‐defining cancers diagnosed in Southern Alberta before and after the introduction of HAART.ResultsA total of 2137 patients with 9265 person‐years of HIV follow‐up care were reviewed. One hundred and forty‐three cases of KS, 64 cases of NHL and 11 cases of invasive cervical cancer/dysplasia were identified. KS and NHL together accounted for 15% of clinical presentations with an AIDS‐defining illness that led to the HIV diagnosis. Following the introduction of HAART, the reduced number of severely immunocompromised patients was associated with 92 and 84% reductions in new diagnoses of KS and NHL, respectively, which were seen mainly in clinic patients declining or failing HAART. Crude reductions of 94 and 65% in mortality from KS and NHL, respectively, were also seen. The prevalences of KS, NHL and invasive cervical cancer/dysplasia have recently stabilized at 3, 1 and 5% of the population, respectively.ConclusionsThe introduction of HAART has dramatically reduced the incidence of KS and NHL and improved survival from these cancers for most patients in HIV care. However, patients still present with KS and NHL leading to their HIV diagnosis.
CD4 percentage is an independent predictor of survival in patients starting antiretroviral therapy with absolute CD4 cell counts between 200 and 350 cells/μL
Authors: Moore DM , Hogg RS , Yip B , Craib K , Wood E , Montaner JSG 
Published: July 2006

ObjectiveTo determine the prognostic value of baseline CD4 percentage in terms of patient survival in comparison to absolute CD4 cell counts for HIV‐positive patients initiating highly active antiretroviral therapy (HAART).MethodsA population‐based cohort study of 1623 antiretroviral therapy‐naïve HIV‐positive individuals who initiated HAART between 1 August 1996 and 30 June 2002 was conducted. Cumulative mortality rates were estimated using Kaplan–Meier methods. Cox proportional hazards regression was used to model the effect of baseline CD4 strata and CD4 percentage strata and other prognostic variables on survival. A subgroup analysis was conducted on 417 AIDS‐free subjects with baseline CD4 counts between 200 and 350 cells/μL.ResultsIn multivariate models, low CD4 percentages were associated with increased risk of death [CD4%<5, relative hazard (RH)=4.46; CD4% 5–14, RH=2.43; P<0.01 for both] when compared with those subjects with an initial CD4 fraction of 15% or greater, but had less predictive value than absolute CD4 counts. In subgroup analyses where absolute CD4 strata were not associated with mortality, a baseline CD4 fraction below 15% [RH=2.71; 95% confidence interval (CI) 1.20–6.10], poor adherence to therapy and baseline viral load >100 000 HIV‐1 RNA copies/mL were associated with an increased risk of death.ConclusionCD4 percentages below 15% are independent predictors of mortality in AIDS‐free patients starting HAART, including those with CD4 counts between 200 and 350 cells/μL. CD4 percentage should be considered for inclusion in guidelines used to determine when to start therapy.
Mutational and bioinformatics analysis of proline‐ and glycine‐rich motifs in vesicular acetylcholine transporter
Authors: Chandrasekaran Ananda , Ojeda Ana M. , Kolmakova Natalia G. , Parsons Stanley M. 
Published: July 2006

AbstractThe vesicular acetylcholine transporter (VAChT) contains six conserved sequence motifs that are rich in proline and glycine. Because these residues can have special roles in the conformation of polypeptide backbone, the motifs might have special roles in conformational changes during transport. Using published bioinformatics insights, the amino acid sequences of the 12 putative, helical, transmembrane segments of wild‐type and mutant VAChTs were analyzed for propensity to form non‐α‐helical conformations and molecular notches. Many instances were found. In particular, high propensity for kinks and notches are robustly predicted for motifs D2, C and C′. Mutations in these motifs either increase or decrease Vmax for transport, but they rarely affect the equilibrium dissociation constants for ACh and the allosteric inhibitor, vesamicol. The near absence of equilibrium effects implies that the mutations do not alter the backbone conformation. In contrast, the Vmax effects demonstrate that the mutations alter the difficulty of a major conformational change in transport. Interestingly, mutation of an alanine to a glycine residue in motif C significantly increases the rates for reorientation across the membrane. These latter rates are deduced from the kinetics model of the transport cycle. This mutation is also predicted to produce a more flexible kink and tighter tandem notches than are present in wild‐type. For the full set of mutations, faster reorientation rates correlate with greater predicted propensity for kinks and notches. The results of the study argue that conserved motifs mediate conformational changes in the VAChT backbone during transport.
The hereditary spastic paraplegia protein spartin localises to mitochondria
Authors: Lu JianPing , Rashid Faiza , Byrne Paula C. 
Published: July 2006

AbstractHereditary spastic paraplegia describes a diverse group of disorders characterized by progressive paraparesis primarily affecting lower limbs. In Troyer syndrome, an autosomal recessive form of hereditary spastic paraplegia, patients have dysarthria, distal amyotrophy, developmental delay and short stature in addition to spastic paraparesis. It is caused by a frameshift mutation (1110delA) in SPG20 leading to premature truncation of spartin, a protein with no known function. The objective of this study was to determine the subcellular localization of spartin and investigate the effect of the 1110delA mutation. We observed cytoplasmic expression of spartin in all transfected cell lines. Using superimposed organelle markers or immunocytochemistry staining, we established that spartin localizes to mitochondria and that this localization is dependent on sequences in the C‐terminal region. Mutant spartin containing the 1110delA mutation has lost mitochondrial localization. Immunocytochemistry staining using anti‐alpha‐tubulin antibody provided evidence for partial co‐localization of spartin with microtubules. Analysis of fluorescence resonance energy transfer indicated that sequences in the amino terminal are important in mediating microtubule interaction. This study provides the first evidence of spartin subcellular localization and identifies it as the third mitochondrial protein implicated in hereditary spastic paraplegia. Our results suggest that Troyer syndrome may be due to defective microtubule‐mediated trafficking of mitochondria and/or mitochondrial dysfunction.