Secular evolution versus hierarchical merging: galaxy evolution along the Hubble sequence, in the field and rich environments

In the current galaxy formation scenarios, two physical phenomena are invoked to build disk galaxies: hierarchical mergers and more quiescent external gas accretion, coming from intergalactic filaments. Although both are thought to play a role, their relative importance is not known precisely. Here we consider the constraints on these scenarios brought by the observation-deduced star formation history on the one hand, and observed dynamics of galaxies on the other hand: the high frequency of bars and spirals, the high frequency of perturbations such as lopsidedness, warps, or polar rings. All these observations are not easily reproduced in simulations without important gas accretion. N-body simulations taking into account the mass exchange between stars and gas through star formation and feedback, can reproduce the data, only if galaxies double their mass in about 10 Gyr through gas accretion. Warped and polar ring systems are good tracers of this accretion, which occurs from cold gas which has not been virialised in the system's potential. The relative importance of these phenomena are compared between the field and rich clusters. The respective role of mergers and gas accretion vary considerably with environment.Comment: 18 pages, 8 figures, review paper to "Penetrating Bars through Masks of Cosmic Dust: the Hubble Tuning Fork Strikes a New Note", Pilanesberg, ed. D. Block et al., Kluwe

The Distribution of Dust and Gas in Elliptical Galaxies

Results from IRAS and recent optical CCD surveys are examined to discuss the distribution and origin of dust and ionized gas in elliptical galaxies. In strong contrast with the situation among spiral galaxies, masses of dust in elliptical galaxies as derived from optical extinction are an order of magnitude LOWER than those derived from IRAS data. I find that this dilemma can be resolved by assuming the presence of a diffusely distributed component of dust which is not detectable in optical data. The morphology of dust lanes and their association with ionized gas in elliptical galaxies argues for an external origin of BOTH components of the ISM.Comment: Invited talk given at conference on "NEW EXTRAGALACTIC PERSPECTIVES IN THE NEW SOUTH AFRICA: Changing Perceptions of the Morphology, Dust Content and Dust-Gas Ratios in Galaxies", Held in Johannesburg, South Africa, during January 22-26, 1996. Proceedings will be edited by D.L. Block and published by Kluwer, Dordrecht, The Netherlands. uuencoded, gzipped LaTeX file of 8 pages; figures included as PostScript files (enclosed). Uses crckapb.sty (enclosed) and psfig.st

A histomorphometric meta-analysis of sinus elevation with various grafting materials

Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone (DFDBA), hydroxyapatite, β-tricalcium phosphate (β-TCP), anorganic deproteinized bovine bone and combination of these and others. Up to now a subject of controversy in maxillofacial surgery and dentistry is, what is the most appropriate graft material for sinus floor augmentation

Association Rate Constants of Ras-Effector Interactions Are Evolutionarily Conserved

Evolutionary conservation of protein interaction properties has been shown to be a valuable indication for functional importance. Here we use homology interface modeling of 10 Ras-effector complexes by selecting ortholog proteins from 12 organisms representing the major eukaryotic branches, except plants. We find that with increasing divergence time the sequence similarity decreases with respect to the human protein, but the affinities and association rate constants are conserved as predicted by the protein design algorithm, FoldX. In parallel we have done computer simulations on a minimal network based on Ras-effector interactions, and our results indicate that in the absence of negative feedback, changes in kinetics that result in similar binding constants have strong consequences on network behavior. This, together with the previous results, suggests an important biological role, not only for equilibrium binding constants but also for kinetics in signaling processes involving Ras-effector interactions. Our findings are important to take into consideration in system biology approaches and simulations of biological networks

Dispersal of Adult Black Marlin (Istiompax indica) from a Great Barrier Reef Spawning Aggregation

The black marlin (Istiompax indica) is one of the largest bony fishes in the world with females capable of reaching a mass of over 700 kg. This highly migratory predator occurs in the tropical regions of the Pacific and Indian Oceans, and is the target of regional recreational and commercial fisheries. Through the sampling of ichthyoplankton and ovaries we provide evidence that the relatively high seasonal abundance of black marlin off the Great Barrier Reef is, in fact, a spawning aggregation. Furthermore, through the tracking of individual black marlin via satellite popup tags, we document the dispersal of adult black marlin away from the spawning aggregation, thereby identifying the catchment area for this spawning stock. Although tag shedding is an issue when studying billfish, we tentatively identify the catchment area for this stock of black marlin to extend throughout the Coral Sea, including the waters of Papua New Guinea, the Solomon Islands, Micronesia, New Caledonia, Kiribati, Vanuatu, Fiji, Tuvalu and Nauru

Increasing tumoral 5-fluorouracil concentrations during a 5-day continuous infusion: a microdialysis study

Purpose: Response to anticancer therapy is believed to be directly related to the concentration of the anticancer drug in the tumor itself. Assessment of intra-tumor drug pharmacokinetics can be helpful to gain more insight into mechanisms involved in the (in)sensitivity of tumors to anticancer therapy. We explored the pharmacokinetics of 5-fluorouracil in both plasma and tumor tissue during a 5-day continuous infusion of 5-fluorouracil in patients with cancer. Sampling for measurement of 5-fluorouracil in tumor tissue was performed using microdialysis. Experimental design: In seven patients with an accessible (sub)cutaneous tumor treated with a continuous 5-fluorouracil infusion, plasma and microdialysate samples from tumor and normal adipose tissue were collected over a period of 5 days. Results: For six patients, drug concentrations in both tumor tissue and plasma were available. Concentration-time curves of unbound 5-fluorouracil were lower in tumor tissue compared to the curves in plasma, but exposure ratios of tumor tissue versus plasma increased during the 5-day infusion period. The presence of circadian rhythmicity of 5-fluorouracil pharmacokinetics in the tumor itself was demonstrated as 5-fluorouracil concentrations in tumor extracellular fluid were higher during the night than during daytime. Conclusion: Microdialysis was successfully employed in patients with cancer during a continuous 5-day 5-fluorouracil infusion. Plasma and tumor pharmacokinetics of 5-fluorouracil differed substantially with increasing 5-fluorouracil concentrations in tumor over time, possibly resulting from a lowered interstitial fluid pressure by 5-fluorouracil itself. This microdialysis 5-fluorouracil model might be useful to monitor the effect of drug delivery modulating strategies in future studies

The broad spectrum of unbearable suffering in end of life cancer studied in dutch primary care

<p>Abstract</p> <p>Background</p> <p>Unbearable suffering most frequently is reported in end-of-life cancer patients in primary care. However, research seldom addresses unbearable suffering. The aim of this study was to comprehensively investigate the various aspects of unbearable suffering in end-of-life cancer patients cared for in primary care.</p> <p>Methods</p> <p>Forty four general practitioners recruited end-of-life cancer patients with an estimated life expectancy of half a year or shorter. The inclusion period was three years, follow-up lasted one additional year. Practices were monitored bimonthly to identify new cases. Unbearable aspects in five domains and overall unbearable suffering were quantitatively assessed (5-point scale) through patient interviews every two months with a comprehensive instrument. Scores of 4 (serious) or 5 (hardly can be worse) were defined unbearable. The last interviews before death were analyzed. Sources providing strength to bear suffering were identified through additional open-ended questions.</p> <p>Results</p> <p>Seventy six out of 148 patients (51%) requested to participate consented; the attrition rate was 8%, while 8% were alive at the end of follow-up. Sixty four patients were followed up until death; in 60 patients interviews were complete. Overall unbearable suffering occurred in 28%. A mean of 18 unbearable aspects was present in patients with serious (score 4) overall unbearable suffering. Overall, half of the unbearable aspects involved the domain of traditional medical symptoms. The most frequent unbearable aspects were weakness, general discomfort, tiredness, pain, loss of appetite and not sleeping well (25%-57%). The other half of the unbearable aspects involved the domains of function, personhood, environment, and nature and prognosis of disease. The most frequent unbearable aspects were impaired activities, feeling dependent, help needed with housekeeping, not being able to do important things, trouble accepting the situation, being bedridden and loss of control (27%-55%). The combination of love and support was the most frequent source (67%) providing strength to bear suffering.</p> <p>Conclusions</p> <p>Overall unbearable suffering occurred in one in every four end-of-life cancer patients. Half of the unbearable aspects involved medical symptoms, the other half concerned psychological, social and existential dimensions. Physicians need to comprehensively assess suffering and provide psychosocial interventions alongside physical symptom management.</p

Combining vitamin C and carotenoid biomarkers better predicts fruit and vegetable intake than individual biomarkers in dietary intervention studies.

The aim of this study was to determine whether combining potential biomarkers of fruit and vegetables is better at predicting FV intake within FV intervention studies than single biomarkers