Experimental Characterisation of the Fire Behaviour of Thermal Insulation Materials for a Performance-Based Design Methodology

A novel performance-based methodology for the quantitative fire safe design of building assemblies including insulation materials has recently been proposed. This approach is based on the definition of suitable thermal barriers in order to control the fire hazards imposed by the insulation. Under this framework, the concept of “critical temperature” has been used to define an initiating failure criterion for the insulation, so as to ensure there will be no significant contribution to the fire nor generation of hazardous gas effluents. This paper proposes a methodology to evaluate this “critical temperature” using as examples some of the most common insulation materials used for buildings in the EU market, i.e. rigid polyisocyanurate foam, rigid phenolic foam, rigid expanded polystyrene foam and low density flexible stone wool. A characterisation of these materials, based on a series of ad-hoc Cone Calorimeter and thermo-gravimetric experiments, serves to establish the rationale behind the quantification of the critical temperature. The temperature of the main peak of pyrolysis, obtained from differential thermo-gravimetric analysis under a nitrogen atmosphere at low heating rates, is proposed as the “critical temperature” for materials that do not significantly shrink and melt, i.e. charring insulation materials. For materials with shrinking and melting behaviour it is suggested that the melting point could be used as “critical temperature”. Conservative values of “critical temperature” proposed are 300°C for polyisocyanurate, 425°C for phenolic foam and 240°C for expanded polystyrene. The concept of a “critical temperature” for the low density stone wool is examined in the same manner and found to be non-applicable due to the inability to promote a flammable mixture. Additionally, thermal inertia values required for the performance-based methodology are obtained for PIR and PF using a novel approach, providing thermal inertia values within the range 4.5 to 6.5\ua0×\ua010\ua0W\ua0s\ua0K\ua0m

Limited β₂-adrenoceptor haplotypes display different agonist mediated airway responses in asthmatics

<p>Abstract</p> <p>Background</p> <p><it>In vitro </it>and some <it>in vivo </it>studies suggested that genetic haplotypes may have an impact on β₂-agonist mediated airway responses in asthmatics. Due to strong linkage disequilibrium the single nucleotide polymorphisms (SNPs) in the β₂-adrenoceptor gene result in only a limited number of haplotypes. We intended to evaluate the impact of β₂-adrenoceptor haplotypes on β₂-agonist mediated airway responses and the development of tolerance in mild to moderate asthmatics.</p> <p>Methods</p> <p>Patients were genotyped for the part of the β₂-adrenoceptor gene with a known bearing on receptor function and regulation. Cumulative dose response curves of fenoterol versus PD₂₀methacholine and FEV₁were constructed after 2 week treatment periods with either terbutaline or placebo in a double blind, randomised and cross-over design. Analysis of the dose response curves was based on a repeated measurement analysis of covariance.</p> <p>Results</p> <p>In our study population comprising 45 asthmatic patients, we found three limited allelic haplotypes, resulting in six different genotypes. Our data support the existence of differences between these six genotypes both in the shape of the dose response relationship of the β₂-adrenoceptor agonist fenoterol as well as in the propensity to develop tolerance for these effects by pre-treatment with terbutaline. However, this could only be substantiated for the endpoint PD₂₀methacholine.</p> <p>Conclusion</p> <p>Between β₂-adrenoceptor genotypes differences exist both in baseline β₂-agonist induced airway responses as well as in the propensity to develop tolerance during maintenance β₂-agonist therapy. The net differences after two weeks of therapy are, however, of magnitudes that are unlikely to be of clinical significance.</p

Exploring the power of high-level postgraduate international partnership work based learning programmes

This chapter explores students’ reflections of their experiential learning whilst enrolled on an HE work based learning (WBL) international internship programme jointly developed by the University of Chester and the Mountbatten Institute. The chapter commences with some background to help set in context why these two organisations came together to form this unique inter-organisational partnership involving the partner delivering and assessing, and the HEI accrediting the programme. Then using data gained from student evaluations together with quotes obtained from students’ reflective learning logs, submitted as part of their final project at the end of the taught element of the programme, the chapter explores students’ perceptions of what they perceive they have gained from this experience which they can take forward into their future careers. As such it provides a unique insight into the nature and value of this international learning experience

Haplotype tagging for the identification of common disease genes

Genome-wide linkage disequilibrium (LD) mapping of common disease genes could be more powerful than linkage analysis if the appropriate density of polymorphic markers were known and if the genotyping effort and cost of producing such an LD map could be reduced. Although different metrics that measure the extent of LD have been evaluated1, 2, 3, even the most recent studies2, 4 have not placed significant emphasis on the most informative and cost-effective method of LD mapping—that based on haplotypes. We have scanned 135 kb of DNA from nine genes, genotyped 122 single-nucleotide polymorphisms (SNPs; approximately 184,000 genotypes) and determined the common haplotypes in a minimum of 384 European individuals for each gene. Here we show how knowledge of the common haplotypes and the SNPs that tag them can be used to (i) explain the often complex patterns of LD between adjacent markers, (ii) reduce genotyping significantly (in this case from 122 to 34 SNPs), (iii) scan the common variation of a gene sensitively and comprehensively and (iv) provide key fine-mapping data within regions of strong LD. Our results also indicate that, at least for the genes studied here, the current version of dbSNP would have been of limited utility for LD mapping because many common haplotypes could not be defined. A directed re-sequencing effort of the approximately 10% of the genome in or near genes in the major ethnic groups would aid the systematic evaluation of the common variant model of common disease

Association of beta2 adrenergic receptor polymorphisms and related haplotypes with triglyceride and LDL-cholesterol levels.

Adrenergic receptors regulate lipid mobilization, energy expenditure and glycogen breakdown. The beta(2) adrenergic receptor (beta(2)-AR) gene may constitute a potential candidate gene to explain part of the genetic predisposition to human obesity and correlated traits. With regard to the association between beta(2)-AR gene polymorphisms and obesity-related metabolic disorders, published reports give conflicting results. We investigated the role of three polymorphisms, and related haplotypes of the beta(2)-AR in the obesity and related traits in a cohort of overweight/obese subjects. We characterized one single nucleotide polymorphism (SNP) in the promoter region (5'LC-Cys19Arg) and two in the coding region (Gly16Arg and Gln27Glu) of the beta(2)-AR in 642 consecutively recruited overweight/obese subjects in whom extensive clinical and biochemical analysis was performed. The effect of the polymorphisms on quantitative variables was investigated using multiple linear regression analysis. 5'LC-Cys19 homozygous showed higher triglyceride and LDL-cholesterol levels compared to 5'LC-Arg19 homozygous (P=0.03 and P=0.01, respectively). Similar increase in triglyceride and LDL-cholesterol levels was observed for Arg/Arg genotype compared to Gly/Gly genotype of Gly16Arg polymorphism (P=0.02 and P=0.01, respectively) and for Gln/Gln genotype compared to Glu/Glu genotype of the Gln27Glu polymorphism (P=0.01 and P=0.03, respectively). The 5'LC-Cys(19)Arg(16)Gln(27) haplotype determined a significant increase in triglyceride and LDL-cholesterol levels compared to 5'LC-Arg(19)Gly(16)Glu(27) haplotype (P=0.05 and P=0.02, respectively). Our findings provide additional weight to previous observations on the influence of these three genetic variants on lipid phenotypes; particularly on the increase of triglycerides and LDL-cholesterol levels in overweight/obese subjects carrying the 5'LC-Cys(19)Arg(16)Gln(27) haplotype