Bilirubin as an Anti-oxidant for Surgical Stress: A Preliminary Report of Bilirubin Oxidative Metabolites

Background Bilirubin has been recognized as an antioxidant. The purpose of this study was to examine whether bilirubin would act as an antioxidant for surgical stress in humans. Materials and Methods Serum bilirubin and urinary bilirubin oxidative metabolites (BOM) were measured in 96 patients who underwent surgery. The antioxidant activity of bilirubin was assessed using BOM measured by enzyme-linked immunosorbent assay with an anti-bilirubin monoclonal antibody. Results Serum bilirubin levels increased after surgery in all 96 patients (p<0.01), but did not correlate with operation time or blood loss (p=0.53 and p=0.28, respectively). BOM increased only in patients with major surgeries (p=0.048). Significant correlations between BOM and operation time and blood loss were found (p<0.01). Conclusions Bilirubin appears to act as an antioxidant for invasive surgery in humans. Urinary BOM could be a reliable marker for the degree of surgical stress

The effect of inhomogeneous expansion on the supernova observations

We consider an inhomogeneous but spherically symmetric Lemaitre-Tolman-Bondi model to demonstrate that spatial variations of the expansion rate can have a significant effect on the cosmological supernova observations. A model with no dark energy but a local Hubble parameter about 15% larger than its global value fits the supernova data better than the homogeneous model with the cosmological constant. The goodness of the fit is not sensitive to inhomogeneities in the present-day matter density, and our best fit model has Omega_M ~ 0.3, in agreement with galaxy surveys. We also compute the averaged expansion rate, defined by the Buchert equations, of the best fit model and show explicitly that there is no average acceleration.Comment: minor corrections to match the version published in JCA

All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: minor corrections to some figures and captions, clarification of some points in the text, added references, added new paragraph with results on atom-resonator interactio

Učinkovitost u zadacima fine motorike i prostornih odnosa tijekom menstrualnog ciklusa

Various studies have shown fl uctuations in task performance during the menstrual cycle. The aim of this study was to see the effects of the menstrual cycle on performing fi ne motor and spatial tasks of different level of complexity in twenty students aged 18 to 21 years, with regular menstrual cycle (28 to 30 days). The students performed O’Connor Finger Dexterity Test and mental rotation test during the menstrual, late follicular, and midluteal phase. Before the tests were performed, we administered Spielberger’s State-Trait Anxiety Inventory for each phase. After the tasks were completed, the subjects ranked their diffi culty on Borg’s scale. The results showed the best performance in both tests in the midluteal phase (with sex hormones at their peak). The anxiety level and task diffi culty ranking were the highest in the menstrual phase, when the hormone levels were the lowest.Različita su istraživanja pokazala promjene učinkovitosti tijekom menstrualnog ciklusa. U zadacima u kojima su uspješnije žene, najveća učinkovitost događa se tijekom kasne folikularne ili srednje lutealne faze. U zadacima u kojima su pak uspješniji muškarci najveća je učinkovitost nađena u menstrualnoj fazi. Na osnovi uporabe zadataka fi ne motorike i prostornih zadataka različitih razina kompleksnosti, cilj ovog istraživanja bio je ispitati utjecaj menstrualnog ciklusa na kognitivne funkcije. U istraživanju je sudjelovalo dvadeset ispitanica, dobi od 18 do 21 godinu, s redovitim menstrualnim ciklusima (28 do 30 dana). Ispitanice su izvodile O’Connorov deksterimetar i zadatke mentalne rotacije tijekom menstrualne, kasne folikularne i srednje lutealne faze. Prije izvođenja zadataka, u svakoj fazi ciklusa primijenjen je Spielbergerov upitnik stanja anksioznosti. Nakon izvođenja zadataka, ispitanice su procjenjivale njihovu težinu na Borgovoj skali. Rezultati su pokazali najbolju učinkovitost u oba zadatka u fazi visokih razina spolnih hormona (srednja lutealna faza). Stanje anksioznosti i procijenjene težine zadataka bili su najviši u menstrualnoj fazi, kada su razine spolnih hormona najniže

Accelerated expansion from structure formation

We discuss the physics of backreaction-driven accelerated expansion. Using the exact equations for the behaviour of averages in dust universes, we explain how large-scale smoothness does not imply that the effect of inhomogeneity and anisotropy on the expansion rate is small. We demonstrate with an analytical toy model how gravitational collapse can lead to acceleration. We find that the conjecture of the accelerated expansion being due to structure formation is in agreement with the general observational picture of structures in the universe, and more quantitative work is needed to make a detailed comparison.Comment: 44 pages, 1 figure. Expanded treatment of topics from the Gravity Research Foundation contest essay astro-ph/0605632. v2: Added references, clarified wordings. v3: Published version. Minor changes and corrections, added a referenc

Can a dust dominated universe have accelerated expansion?

Recently, there has been suggestions that the apparent accelerated expansion of the universe is due not to a cosmological constant, but rather to inhomogeneities in the distribution of matter. In this work, we investigate a specific class of inhomogeneous models that can be solved analytically, namely the dust-dominated Lemaitre-Tolman-Bondi universe models. We show that they do not permit accelerated cosmic expansion.Comment: 9 pages, 1 figure. v3: Paper shortened and updated. References added. v4: Minor LATEX problem fixed. Submitted to JCA