Algebraic expansions for curvature coupled scalar field models

A late time asymptotic perturbative analysis of curvature coupled complex scalar field models with accelerated cosmological expansion is carried out on the level of formal power series expansions. For this, algebraic analogues of the Einstein scalar field equations in Gaussian coordinates for space-time dimensions greater than two are postulated and formal solutions are constructed inductively and shown to be unique. The results obtained this way are found to be consistent with already known facts on the asymptotics of such models. In addition, the algebraic expansions are used to provide a prospect of the large time behaviour that might be expected of the considered models.Comment: 16 pages, no figures; v2: typos corrected, references adde

Blocking and its response to climate change

Purpose of review: Atmospheric blocking events represent some of the most high-impact weather patterns in the mid-latitudes, yet they have often been a cause for concern in future climate projections. There has been low confidence in predicted future changes in blocking, despite relatively good agreement between climate models on a decline in blocking. This is due to the lack of a comprehensive theory of blocking and a pervasive underestimation of blocking occurrence by models. This paper reviews the state of knowledge regarding blocking under climate change, with the aim of providing an overview for those working in related fields. Recent Findings: Several avenues have been identified by which blocking can be improved in numerical models, though a fully reliable simulation remains elusive (at least, beyond a few days lead time). Models are therefore starting to provide some useful information on how blocking and its impacts may change in the future, although deeper understanding of the processes at play will be needed to increase confidence in model projections. There are still major uncertainties regarding the processes most important to the onset, maintenance and decay of blocking and advances in our understanding of atmospheric dynamics, for example in the role of diabatic processes, continue to inform the modelling and prediction efforts. Summary: The term ‘blocking’ covers a diverse array of synoptic patterns, and hence a bewildering range of indices has been developed to identify events. Results are hence not considered fully trustworthy until they have been found using several different methods. Examples of such robust results are the underestimation of blocking by models, and an overall decline in future occurrence, albeit with a complex regional and seasonal variation. In contrast, hemispheric trends in blocking over the recent historical period are not supported by different methods, and natural variability will likely dominate regional variations over the next few decades

Rule-Based Models of the Interplay between Genetic and Environmental Factors in Childhood Allergy

Peer reviewe

Early mobilization after flexor tendon repair in children

PURPOSE: Aim of the study was to provide an age-adapted rehabilitation protocol for flexor tendon repairs of children and to evaluate a patient series accordingly. METHODS: A modified Kessler's technique was used to repair 49 flexor tendon injuries in 39 children. All children had immediate postoperative mobilization according to the protocol that provides specific guidelines for preschoolers, children and teenagers. Range of motion was monitored and the final results were evaluated retrospectively. RESULTS: All children could be treated successfully according to the protocol with no occurrence of secondary tendon ruptures. Forty finger injuries were evaluated according to the Strickland classification, resulting in a median total active motion of 92.6 % with 29 (72.5 %) excellent results, 8 (20 %) good results, 3 (7.5 %) fair results and no poor result. All 7 thumbs had an excellent result according to the Buck-Gramcko score. There was no significant difference in outcomes between the three age groups. CONCLUSIONS: The rehabilitation protocol provided in this study allows an age-adapted early mobilization of children's hands after flexor tendon injuries. It respects age-specific limitations in rehabilitation and takes a child's superior healing capacity compared to adults into account. The good results and the very low complication rate observed in the present series suggest that the extra effort of early mobilization may be justified

Blood plasma lipidome profile of dairy cows during the transition period

BACKGROUND: The transition period of dairy cows, around parturition and the onset of lactation, involves endocrine and metabolic changes to compensate for an increased energy requirement aggravated by reduced feed intake. Transition cows adjust to the resulting negative energy balance with the mobilization of lipids from the adipose tissues yielding increased blood levels of non-esterified fatty acids and ketone bodies like β-hydroxybutyrate. RESULTS: To study the biochemical adaptations underlying this physiologic adjustment and possible pathologic derangements, we analyzed the blood plasma lipidome of transition cows by ultra-pressure liquid chromatography coupled to high-resolution quadrupole time-of-flight mass spectrometry. The resulting data were processed by principal component analysis, revealing over 60 lipid masses that change in abundance over the test period ranging from two weeks before calving to four weeks postpartum. Further characterization of analytes by tandem mass spectrometry demonstrated that the concentration of triacylglycerides in plasma drops at the day of parturition whereas the plasma level of many phosphatidylcholines and two sphingomyelins increases steadily during early lactation. CONCLUSION: This newly identified shift in phospholipid composition delivers a potential biomarker to detect aberrant metabolic pathways in transition cows and also provides insights into how to prevent and treat associated disorders like fatty liver disease

An IgE-associated polymorphism in STAT6 alters NF-κB binding, STAT6 promoter activity, and MRNA expression.

The IL-4/IL-13 pathway is central for IgE regulation. Signal transducer and activator of transcription 6 (STAT6) is the major transcription factor within this pathway. STAT6 polymorphisms were recently associated with elevated total IgE levels in a genome-wide association study. OBJECTIVE: This study aimed to assess biological mechanisms by which an IgE-associated genetic variation in STAT6 may potentially influence gene expression. METHODS: STAT6 intron 2 carrying either the wild-type C or the polymorphic T allele of the putatively causal single nucleotide polymorphism rs324011 was cloned into STAT6 promoter vectors to investigate their influence on STAT6 promoter activity by in vitro luciferase assays. Transcription factor binding depending on rs324011 was examined by electrophoretic mobility shift assays in Jurkat T cells and primary CD4(+) T cells. Allele-specific STAT6 gene expression of 3 splice variants was studied ex vivo by real-time PCR in 239 individuals. RESULTS: STAT6 intron 2 acts as a silencer regulatory element. The polymorphic T allele at rs324011 (in linkage disequilibrium with the genome-wide association signal and consistently associated with elevated IgE levels in 3 previous studies) increases STAT6 promoter activity significantly in vitro (P < .00001) and gene expression of STAT6 splice variants ex vivo (P < .01) compared with the wild-type C allele. These effects correlate with the creation of a novel, T-allele-specific binding site for the transcription factor nuclear factor-kappaB in T cells. CONCLUSION: The consistently replicated effects of genetic variance in STAT6 on IgE regulation may be explained in part by allele-specific alterations in nuclear factor-kappaB binding at rs324011 and consecutive changes in STAT6 gene expression

Gene expression measurements in the context of epidemiological studies

BACKGROUND: Gene expression measurements became an attractive tool to assess biological responses in epidemiological studies. However, collection of blood samples poses various technical problems. We used gene expression data from two epidemiological studies to evaluate differences between sampling methods, comparability of two methods for measuring RNA levels and stability of RNA samples over time. METHODS: For the PARSIFAL study, PBLC of 1155 children were collected using EDTA tubes in two countries. In the PASTURE study, tubes containing RNA-stabilizing solutions (PAXgene) Blood RNA Tubes; PreAnalytiX) were used to collect cord blood leucocytes of 982 children in five countries. Real-time PCR (conventional single tube assay and high-throughput low density arrays) was used to quantify expression of various innate immunity genes. In 77 PARSIFAL samples, gene expression was measured repeatedly during prolonged storage. RESULTS: In PARSIFAL (EDTA tubes) the median RNA yield after extraction significantly differed between the two centres (70 and 34 ng/microl). Collecting blood into an RNA-stabilizing solution markedly reduced differences in RNA yield in PASTURE (range of medians 91-107 ng/microl). The agreement [Spearman rank correlation (r)] between repeated measurements of gene expression decreased with increasing storage time [e.g., for CD14: r (first/second measurement) = 0.35; r (first/third measurement) = 0.03]. RNA levels measured with either the conventional method or low-density arrays were comparable (r > 0.9). CONCLUSION: Collecting blood samples into tubes containing an RNA-stabilizing solution increases RNA yield and reduces its variability. Long-term storage of samples may lead to RNA degradation, requiring special attention in longitudinal studies