Normal and Anomalous Yield Stresses in a Tial Single Crystal and the Dominating Dislocation Mechanisms

Single crystal γ-TiAl with axial orientation [3 16 15] has been tested in compression between 4K and 1048K and the dislocation structures observed in TEM. The slip plane was found to be (111) over the entire temperature range tested. Three regimes exist in the variation of the yield stress with temperature, whereas the dislocation substructures are of two types, dominated by 30° 1/3[112] and 1/2 < 110] dislocations respectively. The anomalous yield stress is associated with 1/2 < 110] dislocations undergoing frequent cross-slip off the (111) plane.

Discriminating preoperative features of pleuropulmonary blastomas (PPB) from congenital cystic adenomatoid malformations (CCAM): a retrospective, age-matched study

BACKGROUND

The etiopathogenesis of pleuropulmonary blastoma (PPB) and its relationship to congenital cystic adenomatoid malformation (CCAM) remain controversial. Our recent analysis indicates that both the co-incidental occurrence and the outcome of PPB among CCAM patients are significant. We report here on our efforts to determine clinical and radiological features discriminating PPB from CCAM preoperatively.

MATERIALS & METHODS

A retrospective analysis of all patients treated for PPB and CCAM between 1981 and 2008 at 2 tertiary academic centers under a centralized, single payer healthcare system was performed (REB#1000013239). Clinical, radiological and demographic data were analyzed. PPB patients were secondarily age matched with CCAM patients (± 10% age difference in months), and clinical, radiological and demographic variables were compared. Descriptive statistics and non-parametric analysis were used.

RESULTS

A total of 10 PPB patients was identified. Median age at diagnosis was 24 months; the male to female ratio was 5:5. No PPB patients had an antenatal diagnosis (p<0.01). 9 were symptomatic, with symptoms including dyspnea (7/10), upper respiratory infection (6/10), poor weight gain (3/10), and 1 patient was asymptomatic. 5 of 10 patients had solid parts on CT, of which 4 out of 5 were diagnosed preoperatively as PPB and 1 out of 5 as CCAM. 5 of 10 were predominantly cystic of which none was diagnosed preoperatively as PPB (p=0.0476). Given that most CCAM patients are now diagnosed antenatally, only 5 PPB patients could be age-matched with CCAM patients. In the predominantly cystic PPB patients (n=5), no significant discriminating clinical and radiological features were identifiable when compared preoperatively with age-matched CCAM patients.

CONCLUSION

PPB patients continue to represent a diagnostic challenge. Asymptomatic and predominantly cystic PPB remain indistinguishable from CCAM preoperatively. A high index of suspicion for PPB must be considered in any child presenting with cystic lung lesions beyond early infancy, particularly in a child with poor weight gain.

Modelling supply and demand of bioenergy from short rotation coppice and Miscanthus in the UK

Biomass from lignocellulosic energy crops can contribute to primary energy supply in the short term in heat and electricity applications and in the longer term in transport fuel applications. This paper estimates the optimal feedstock allocation of herbaceous and woody lignocellulosic energy crops for England and Wales based on empirical productivity models. Yield maps for Miscanthus, willow and poplar, constrained by climatic, soil and land use factors, are used to estimate the potential resource. An energy crop supply-cost curve is estimated based on the resource distribution and associated production costs. The spatial resource model is then used to inform the supply of biomass to geographically distributed demand centres, with co-firing plants used as an illustration. Finally, the potential contribution of energy crops to UK primary energy and renewable energy targets is discussed.

The transcriptome of Populus in elevated CO reveals increased anthocyanin biosynthesis during delayed autumnal senescence

*The delay in autumnal senescence that has occurred in recent decades has been linked to rising temperatures. Here, we suggest that increasing atmospheric CO2 may partly account for delayed autumnal senescence and for the first time, through transcriptome analysis, identify gene expression changes associated with this delay. *Using a plantation of Populus x euramericana grown in elevated [CO2] (e[CO2]) with free-air CO2 enrichment (FACE) technology, we investigated the molecular and biochemical basis of this response. A Populus cDNA microarray was used to identify genes representing multiple biochemical pathways influenced by e[CO2] during senescence. Gene expression changes were confirmed through real-time quantitative PCR, and leaf biochemical assays. *Pathways for secondary metabolism and glycolysis were significantly up-regulated by e[CO2] during senescence, in particular, those related to anthocyanin biosynthesis. Expressed sequence tags (ESTs) representing the two most significantly up-regulated transcripts in e[CO2], LDOX (leucoanthocyanidin dioxgenase) and DFR (dihydroflavonol reductase), gave (e[CO2]/ambient CO(2) (a[CO2])) expression ratios of 39.6 and 19.3, respectively. *We showed that in e[CO2] there was increased autumnal leaf sugar accumulation and up-regulation of genes determining anthocyanin biosynthesis which, we propose, prolongs leaf longevity during natural autumnal senescence.