Lack of major gender-related differences in patients undergoing elective endovascular or surgical repair of abdominal aortic aneurysm.

AIM: The aim of this single center retrospective study was to determine gender-related differences in patients undergoing repair of aortic aneurysm. METHODS: A total of 296 consecutive patients with an abdominal aneurysm undergoing elective endovascular or surgical repair was included in the study. Among these, 24 (8.1%) were females and 272 (91.9%) were males. Demographic and clinical characteristics as well as laboratory values in terms of any potential gender-specific differences were compared. RESULTS: Females were significantly older at the time of repair than males. No gender-related differences were found analysing major clinical and laboratory parameters. CONCLUSIONS: The clinical and laboratory profile with which males and females present at the time of elective endovascular or surgical repair for aortic aneurysm is very similar. It does not reveal any potential gender-specific risk constellation. It eventually remains unclear why the prevalence of aortic aneurysm is higher in male than in females.

Stochastic phase oscillators and circadian bioluminescence recordings.

Cultured circadian oscillators from peripheral tissues were recently shown to be both cell-autonomous and self-sustained. Therefore, the dominant cause for amplitude reduction observed in bioluminescence recordings of cultured fibroblasts is desynchronization, rather than the damping of individual oscillators. Here, we review a generic model for quantifying luminescence signals from biochemical oscillators, based on noisy-phase oscillators. Our model incorporates three essential features of circadian clocks: the stability of the limit cycle, fluctuations, and intercellular coupling. The model is then used to analyze bioluminescence recordings from immortalized and primary fibroblasts. Fits to population recordings allow simultaneous estimation of the stability of the limit cycle (or equivalently, the stiffness of individual frequencies), the period dispersion, and the interaction strength between cells. Consistent with other work, coupling is found to be weak and insufficient to synchronize cells. Interestingly, we find that frequency fluctuations remain correlated for longer periods than one clock cycle, which is confirmed from individual cell recordings. We discuss briefly how to link the generic model with more microscopic models, which suggests mechanisms by which circadian oscillators resist fluctuations and maintain accurate timing in the periphery.

Circadian regulation of gene expression systems in the Drosophila head.

Mechanisms composing Drosophila's clock are conserved within the animal kingdom. To learn how such clocks influence behavioral and physiological rhythms, we determined the complement of circadian transcripts in adult Drosophila heads. High-density oligonucleotide arrays were used to collect data in the form of three 12-point time course experiments spanning a total of 6 days. Analyses of 24 hr Fourier components of the expression patterns revealed significant oscillations for approximately 400 transcripts. Based on secondary filters and experimental verifications, a subset of 158 genes showed particularly robust cycling and many oscillatory phases. Circadian expression was associated with genes involved in diverse biological processes, including learning and memory/synapse function, vision, olfaction, locomotion, detoxification, and areas of metabolism. Data collected from three different clock mutants (per(0), tim(01), and Clk(Jrk)), are consistent with both known and novel regulatory mechanisms controlling circadian transcription.

Nuclear spin relaxation rates in two-Leg spin ladders

Using the transfer-matrix density-matrix renormalization group method, we study the nuclear spin relaxation rate 1/T(1) in the two-leg s = 1 / 2 ladder as a function of the interchain (J( perpendicular)) and intrachain (J( parallel)) couplings. In particular, we separate the q(y) = 0 and pi contributions and show that the latter contribute significantly to the copper relaxation rate (63)(1/T(1)) in the experimentally relevant coupling and temperature range. We compare our results to both theoretical predictions and experimental measures on ladder materials.

Reactive hall response

The zero temperature Hall constant R(H), described by reactive (nondissipative) conductivities, is analyzed within linear response theory. It is found that in a certain limit R(H) is directly related to the density dependence of the Drude weight, implying a simple picture for the change of sign of charge carriers in the vicinity of a Mott-Hubbard transition. This novel formulation is applied to the calculation of R(H) in quasi-one-dimensional and ladder prototype interacting electron systems.