1,721,144 research outputs found
Modelling the ecology of phototrophic-heterotrophic biofilms
No full textA mathematical model describing the microbial interactions in phototrophic-heterotrophic biofilms is presented. The main phenomena and factors involved in the model include: biomass growth and decay, substrates production, diffusion and consumption, biological invasion of planktonic species and detachment. In particular, non linear hyperbolic PDEs describe the growth of the microbial species while quasi-linear parabolic PDEs govern the dynamics of substrates and invading species. The whole system of PDEs is considered in a free boundary domain. The following syntrophic interactions are also modelled: the exchange of dissolved oxygen, organic carbon and inorganic carbon produced and released by phototrophs and heterotrophs, respectively. The positive effect of heterotrophic pioneers on the phototrophic growth is modelled by introducing a phototrophic colonization rate depending on the EPS fraction in the biofilm. Numerical simulations are performed to test model accuracy. Simulation results reproduce the main symbiotic mechanisms between phototrophs and heterotrophs reported in literature, such as the positive effect of heterotrophic pioneers and their EPS production on phototrophic growth and the effects of phototrophic organic carbon release on the invasion and growth of heterotrophic bacteria. Furthermore, model results highlight the role played by heterotrophic species under photoinhibition conditions, which provide a positive shading contribution to phototrophic growth. Light is confirmed as the most significant factor in the ecology of phototrophic-heterotrophic biofilms. Such results confirm the accuracy of the model that correctly predicts the evolution of a phototrophic-heterotrophic biofilm and the main phenomena involved, and can be seen as an auxiliary tool in different industrial applications, such as wastewater treatment and bioenergy production
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Therapeutic approach of children with endocrine diseases in otorhinolaryngoiatric surgery
No full textAlmost all endocrine disorders may cause adverse complications or a difficult postoperative course if they are not recognized or adequately managed. Diabetes is the most commonly encountered endocrinopathy and there is increasing evidence that maintenance of normal blood glucose in the perioperative period is necessary to reduce adverse events. The perioperative management of diabetes should be based on the type of diabetes, the medications taken and degree of diabetes control. Thyrotoxicosis is a potentially severe condition that requires medical intervention before surgery. The preparation of a patient with hyperthyroidism depends on the time available before surgery and on the severity of the thyrotoxicosis. Generally, treatment involves a combination of medications that influence the synthesis, secretion and peripheral actions of thyroid hormones. Patients with mild hypothyroidism can undergo elective or emergency surgery without specific perioperative preparation. In case of adrenal insufficiency, supplementation of glucocorticoids (and possibly mineralocorticoids) should be adequately given and individualized on the basis of size and the type of surgical procedure to be performed. Finally, the management of children with diabetes insipidus, before or after a surgical procedure, or with the syndrome of inappropriate secretion of ADH is complicated and may cause severe electrolytic imbalances as well as problems of over- or under-hydration which can be difficult to treat. © Copyright 2006, CIC Edizioni Internazionali, Roma
Dapsone treatment in a girl with severe chronic thrombocytopenic pupura does it work? Don’t touch it!
No full textDapsone has been shown to be effective in treating immune thrombocytopenic purpura (ITP) in adults. In children the experience is limitated. We describe our experience using dapsone in a female with refractory, symptomatic ITP who suffered intracranic haemorrhage and massive gastric bleeding. After treatment platelet counts was more than 100 x 103/μL, and reached 1000x103/μL. Discontinuation resulted in a rapid decrease in platelet counts, with severe intracranial haemorrhage (ICH). The recovery of dapsone led the platelets count to lower values. We suggest that treatment should not be discontinued in responders, at least in children with symptomatic ITP. Additional studies of dapsone in children are warranted
Puberty in insulin-dependent diabetes mellitus (IDDM): growth, sexual maturation and final height
No full text- …
