9,524 research outputs found
Sequence variation in the haemagglutinin-neuraminidase gene of human parainfluenza virus type 3 isolates in the UK
The sequence variation in a 934 base-pair region of the gene encoding the haemagglutinin-neuraminidase of five human parainfluenza virus type 3 (HPIV3) isolates was determined together with that of a prototype UK strain. All of the clinical isolates were from the Manchester area of the UK and were obtained in 1990. 1991 and 1993. The gene segment was amplified by the polymerase chain reaction using HPIVB-specific oligonucleotide primers. The nucleotide homology of the strains was high, around 99% and specific differences in the UK sequences when compared with that of the US prototype strain were identified. In addition, a number of isolate-specific differences were seen. No correlation was detected between the observed nucleotide mutations and the year of isolation, which supports the hypothesis that HPIV3 shows cocirculation of a heterogeneous population of viruses rather than varying with time in a linear fashion. However, the data suggested that geographically-defined genetic lineages of HPIV3 may exist
Assessing dentists' knowledge and experience in restoring endodontically treated teeth using post & cores
OBJECTIVES: The restoration of endodontically, heavily filled teeth has been a challenge for the dental profession for decades. The aims of this study were to investigate dentists' experience and knowledge in the use of post & core when restoring endodontically treated teeth. METHOD: This was a mixed method study incorporating quantitative and qualitative data collection. An online questionnaire was developed and distributed, comprised of 18 questions. It was calculated that 93 respondents were needed to validate the study of which 60% should meet a minimum knowledge requirement. RESULTS: 173 respondents completed the questionnaire. 109 (63% (95%CI56%,70%) demonstrated proficient knowledge of post & core restorations. Recent graduates were more likely to follow current guidelines (F=4.570: P<0.034). As the age of the respondent increases the number of posts placed (F=18.85; p<0.001) and the perceived confidence level increases (Spearman's Rho 0.43: P<0.01). Experience of postgraduate education also positively influenced clinical confidence. CONCLUSION: The placement of post & cores is influenced by age. Confidence is also influenced by age. More evidence on post usage is required and several questions remain to be answered on what drives decision making and perceived long-term success. CLINICAL SIGNIFICANCE: There is a general acceptance of when a post and core restoration should be used. Clinician experience and age can have an impact on what type of restorations are used. Fibre posts are more commonly used due their accessibility and cost
Characterization of spotted hyena, Crocuta crocuta microsatellite loci
We have isolated 10 polymorphic microsatellite loci in the spotted hyena,Crocuta crocuta.The loci displayed between eight and 14 alleles in a minimum of 12 individuals tested.
These loci will be used to investigate relatedness within social groups, the genetic structure of populations, sexual selection, and mate choice in spotted hyenas
Evaluation of mTOR-regulated mRNA translation.
mTOR, the mammalian target of rapamycin, regulates protein synthesis (mRNA translation) by affecting the phosphorylation or activity of several translation factors. Here, we describe methods for studying the impact of mTOR signalling on protein synthesis, using inhibitors of mTOR such as rapamycin (which impairs some of its functions) or mTOR kinase inhibitors (which probably block all functions).To assess effects of mTOR inhibition on general protein synthesis in cells, the incorporation of radiolabelled amino acids into protein is measured. This does not yield information on the effects of mTOR on the synthesis of specific proteins. To do this, two methods are described. In one, stable-isotope labelled amino acids are used, and their incorporation into new proteins is determined using mass spectrometric methods. The proportions of labelled vs. unlabeled versions of each peptide from a given protein provide quantitative information about the rate of that protein's synthesis under different conditions. Actively translated mRNAs are associated with ribosomes in polyribosomes (polysomes); thus, examining which mRNAs are found in polysomes under different conditions provides information on the translation of specific mRNAs under different conditions. A method for the separation of polysomes from non-polysomal mRNAs is describe
Hippocampal Contribution to Context Encoding across Development Is Disrupted following Early-Life Adversity
Context can drastically influence responses to environmental stimuli. For example, a gunshot should provoke a different response at a public park than a shooting range. Little is known about how contextual processing and neural correlates change across human development or about individual differences related to early environmental experiences. Children (N = 60; 8–19 years, 24 exposed to interpersonal violence) completed a context encoding task during fMRI scanning using a delayed match-to-sample design with neutral, happy, and angry facial cues embedded in realistic background scenes. Outside the scanner, participants completed a memory test for context-face pairings. Context memory and neural correlates of context encoding did not vary with age. Larger hippocampal volume was associated with better context memory. Posterior hippocampus was recruited during context encoding, and greater activation in this region predicted better memory for contexts paired with angry faces. Children exposed to violence had poor memory of contexts paired with angry faces, reduced hippocampal volume, and atypical neural recruitment on encoding trials with angry faces, including reduced hippocampal activation and greater functional connectivity between hippocampus and ventrolateral prefrontal cortex (vlPFC). Greater hippocampus-vlPFC connectivity was associated with worse memory for contexts paired with angry faces. Posterior hippocampus appears to support context encoding, a process that does not exhibit age-related variation from middle childhood to late adolescence. Exposure to dangerous environments in childhood is associated with poor context encoding in the presence of threat, likely due to greater vlPFC-dependent attentional narrowing on threat cues at the expense of hippocampus-dependent processing of the broader context
Is \gamma-ray emission from novae affected by interference effects in the 18F(p,\alpha)15O reaction?
The 18F(p,\alpha)15O reaction rate is crucial for constraining model
predictions of the \gamma-ray observable radioisotope 18F produced in novae.
The determination of this rate is challenging due to particular features of the
level scheme of the compound nucleus, 19Ne, which result in interference
effects potentially playing a significant role. The dominant uncertainty in
this rate arises from interference between J\pi=3/2+ states near the proton
threshold (Sp = 6.411 MeV) and a broad J\pi=3/2+ state at 665 keV above
threshold. This unknown interference term results in up to a factor of 40
uncertainty in the astrophysical S-factor at nova temperatures. Here we report
a new measurement of states in this energy region using the 19F(3He,t)19Ne
reaction. In stark contrast with previous assumptions we find at least 3
resonances between the proton threshold and Ecm=50 keV, all with different
angular distributions. None of these are consistent with J\pi= 3/2+ angular
distributions. We find that the main uncertainty now arises from the unknown
proton-width of the 48 keV resonance, not from possible interference effects.
Hydrodynamic nova model calculations performed indicate that this unknown width
affects 18F production by at least a factor of two in the model considered.Comment: 5 pages, 4 figures. Accepted for publication in Phys. Rev. Let
Complexes of tissue-type plasminogen activator and its serpin inhibitor plasminogen-activator inhibitor type 1 are internalized by means of the low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor.
Phosphate selective binding and sensing by halogen bonding tripodal copper( ii ) metallo-receptors in aqueous media â€
Combining the potency of non-covalent halogen bonding (XB) with metal ion coordination, the synthesis and characterisation of a series of hydrophilic XB tripodal Cu(ii) metallo-receptors, strategically designed for tetrahedral anion guest binding and sensing in aqueous media is described. The reported metallo-hosts contain a tripodal C3-symmetric tris-iodotriazole XB donor anion recognition motif terminally functionalised with tri(ethylene glycol) and permethylated β-cyclodextrin functionalities to impart aqueous solubility. Optical UV-vis anion binding studies in combination with unprecedented quantitative EPR anion titration investigations reveal the XB Cu(ii) metallo-receptors exhibit strong and selective phosphate recognition over a range of other monocharged anionic species in competitive aqueous solution containing 40% water, notably outperforming a hydrogen bonding (HB) Cu(ii) metallo-receptor counterpart. Electrochemical studies demonstrate further the capability of the metallo-receptors to sense anions via significant cathodic perturbations of the respective Cu(ii)/Cu(i) redox couple
Separation of VUV/UV photons and reactive particles in the effluent of a He/O2 atmospheric pressure plasma jet
Cold atmospheric pressure plasmas can be used for treatment of living tissues
or for inactivation of bacteria or biological macromolecules. The treatment is
usually characterized by a combined effect of UV and VUV radiation, reactive
species, and ions. This combination is usually beneficial for the effectiveness
of the treatment but it makes the study of fundamental interaction mechanisms
very difficult. Here we report on an effective separation of VUV/UV photons and
heavy reactive species in the effluent of a micro scale atmospheric pressure
plasma jet (-APPJ). The separation is realized by an additional flow of
helium gas under well-defined flow conditions, which deflects heavy particles
in the effluent without affecting the VUV and UV photons. Both components of
the effluent, the photons and the reactive species, can be used separately or
in combination for sample treatment. The results of treatment of a model plasma
polymer film and vegetative Bacillus subtilis and Escherichia coli cells are
shown and discussed. A simple model of the He gas flow and reaction kinetics of
oxygen atoms in the gas phase and at the surface is used to provide a better
understanding of the processes in the plasma effluent. The new jet
modification, called X-Jet for its appearance, will simplify the investigation
of interaction mechanisms of atmospheric pressure plasmas with biological
samples.Comment: 10 pages, 7 figures, submitted to Journal of Physics D: Applied
Physic
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