Methodological differences of the physical and computational model approaches

General principles of modeling, the problem of adequency of models, and the similarity and differences between physical and computational models are discussed.     

Real-time PCR: approaches to data analysis (a review)

The registration of the accumulation of polymerase chain reaction (PCR) products in the course of amplification (real-time PCR) requires specific equipment, i.e., detecting amplifiers capable of recording the level of fluorescence in the reaction tube during amplicon formation. By the time the reaction is completed, researchers obtain DNA accumulation graphs. The review discusses the most promising algorithms of analysis of real-time PCR curves and possible errors, whether caused by the software used or the operators' mistakes. The data included will assist researchers in understanding the features of the method to obtain more reliable results.     

Immunomodulating effect of autohaemotherapy (a literature review)

An analysis is presented of experimental and clinical data from different authors on the stimulating effect of autohaemotherapy with regard to the immunological reactivity of humans and animals as well as in vitro experiments with lymphocytes. Erythrolysate has been found to exert a more powerful effect than intact erythrocytes. The stimulating effect of autohaemotherapy on both irradiated and non-irradiated animals manifests itself in an increase in resistance to infection (increased LD50 in experimental infection), enhanced production of antibodies to microbial and tissue antigens and activated functioning of cell-mediated immune defence mechanisms. The favourable influences on radioresistance and the antitumour effect of authohaemotherapy are described. Induced desensitization plays an important part in the mechanism of action of autohaemotherapy. The administration of large doses of erythrocytes or of erythrolysate results in immunosuppression. Autohaemotherapy does not cause side effects and is feasible both on an in-and out-patient basis.     

Endothelium function in ischemia-reperfusion (a literature review)

Endothelium was shown to be one of the most hypoxia-tolerant mammalian cell types and to be injured in ischemia to a lesser extent than other cells. Alteration in the endothelial function during hypoxia and ischemia protects the organs against ischemic injury. Postischemic reperfusion contributes to endothelial dysfunction and initiates the reperfusion injury. Some data show ischemia/reperfusion to cause a systemic alteration of endothelial function in remote organs.     

Methodological approaches to developing a method of regulated antibiotic biosynthesis]

Methodologic approaches to the development of methods for controlled biosynthesis of antibiotics are discussed with reference to oxytetracycline biosynthesis. The method of acute experiments in conjunction with mathematical methods of experiment planning was used for determination of the substrate concentrations optimal for the culture growth and biosynthesis of oxytetracycline. It was found that such mathematic procedure provided simultaneous determination of optimal concentrations of all the substrates.     

Ways to get work done: a review and systematisation of simplification practices in the LCA literature

Purpose

Within the field of life cycle assessment (LCA), simplifications are a response to the practical restrictions in the context of a study. In the 1990s, simplifications were part of a debate on streamlining within LCA. Since then, many studies have been published on simplifying LCA but with little attention to systematise the approaches available. Also, despite being pervasive during the making of LCA studies, simplifications remain often invisible in the final results. This paper therefore reviews the literature on simplification in LCA in order to systematise the approaches found today.

Methods

A review of the LCA simplification literature was conducted. The systematic search and selection process led to a sample of 166 publications. During the review phase, the conceptual contributions to the simplification discourse were evaluated. A dataset of 163 entries was created, listing the conceptual contributions to the simplification debate. An empirically grounded analysis led to the generative development of a systematisation of simplifications according to their underlying simplifying logic.

Results and discussion

Five simplifying logics were identified: exclusion, inventory data substitution, qualitative expert judgment, standardisation and automation. Together, these simplifying logics inform 13 simplification strategies. The identified logics represent approaches to handle the complexities of product systems and expectations of the users of LCA results with the resources available to the analyst. Each simplification strategy is discussed with regard to its main applications and challenges.

Conclusions

This paper provides a first systematisation of the different simplification logics frequently applied in LCA since the original streamlining discussion. The presented terminology can help making communication about simplification more explicit and transparent, thus important for the credibility of LCA. Despite the pervasiveness of simplification in LCA, there is a relative lack of research on simplification per se, making further research describing simplification as a practice and analysing simplifications methodologically desirable.

     

Hazards of urethane (ethyl carbamate): a review of the literature

Urethane (ethyl carbamate) is used alone or in combination with other drugs to produce anaesthesia in laboratory animals. Although originally studied as a potential phytocide, urethane demonstrated antineoplastic properties when administered to rats with the Walker rat carcinoma 256. Subsequent trials in humans led to its use as a chemotherapeutic agent for various leukaemias. Mice develop pulmonary adenomas earlier in life and at a higher incidence following urethane administration. Urethane's carcinogenic influence is greater in neonatal mice; it also has a transplacental influence in mice. In rats, urethane increases the incidence of pulmonary adenomas, Zymbal Gland tumours, and a variety of other neoplasms. Urethane is absorbed sufficiently from the skin of laboratory animals to produce a transient narcosis. The carcinogenic effect appears to be due to an undefined oncogenic intermediate formed in the blood. Considering the properties urethane demonstrates in animals, the safety of its use by laboratory personnel is in question. However, if appropriate guidelines are followed, urethane should continue to be a useful anaesthetic agent for laboratory animals.