Fat embolism: a rational approach to treatment

Fat embolism following major trauma may be associated with a clinical syndrome with widespread pulmonary and systemic manifestations, the most serious being profound hypoxia with secondary atelectasis, pulmonary edema and pulmonary hypertension, and cerebral depression. Though the origin of the embolic fat is debated, there is evidence to support its origin from both the bone marrow and intravascular chylomicron coalescence.The clinical manifestations are largely explained by a prime assault upon the lung parenchyma and alteration in platelet characteristics.Early recognition and treatment of the condition is essential, adequate oxygenation being of prime importance. Steroids and heparin have been found to be of benefit.     

Design of nucleic acid sequences for DNA computing based on a thermodynamic approach

We have developed an algorithm for designing multiple sequences of nucleic acids that have a uniform melting temperature between the sequence and its complement and that do not hybridize non-specifically with each other based on the minimum free energy (ΔG_min). Sequences that satisfy these constraints can be utilized in computations, various engineering applications such as microarrays, and nano-fabrications. Our algorithm is a random generate-and-test algorithm: it generates a candidate sequence randomly and tests whether the sequence satisfies the constraints. The novelty of our algorithm is that the filtering method uses a greedy search to calculate ΔG_min. This effectively excludes inappropriate sequences before ΔG_min is calculated, thereby reducing computation time drastically when compared with an algorithm without the filtering. Experimental results in silico showed the superiority of the greedy search over the traditional approach based on the hamming distance. In addition, experimental results in vitro demonstrated that the experimental free energy (ΔG_exp) of 126 sequences correlated well with ΔG_min (|R| = 0.90) than with the hamming distance (|R| = 0.80). These results validate the rationality of a thermodynamic approach. We implemented our algorithm in a graphic user interface-based program written in Java.     

On a new law of bone remodeling based on damage elasticity: a thermodynamic approach

Background

Bone tissue is the main element of the human skeleton and is a dynamic tissue that is continuously renewed by bone-resorbing osteoclasts and bone-forming osteoblasts.The bone is also capable of repairing itself and adapting its structure to changes in its load environment through the process of bone remodeling.Therefore, this phenomenon has been gaining increasing interest in the last years and many laws have been developed in order to simulate this process.

Results

In this paper, we develop a new law of bone remodeling in the context of damaged elastic by applying the thermodynamic approach in the case of small perturbations.The model is solved numerically by a finite difference method in the one-dimensional bone structure of a n-unit elements model.

Conclusion

In addition, several numerical simulations are presented that confirm the accuracy and effectiveness of the model.

     

A rational approach to dementia.

Dementia is a common problem facing all medical practitioners and it frequently results in hospitalization and death. This review provides a framework for dealing with dementia in clinical practice that is based on both traditional concepts and recent advances in the understanding of the problem. Distinguishing at the bedside between dementia and other disorders of intellect is emphasized. The main causes of dementia and their clinical characteristics are reviewed and a rational approach to definitive diagnosis is developed. Simple, effective symptomatic forms of therapy are described.     

A rational approach to cancer therapy

A report on the 20th Annual Lorne Cancer Conference, Lorne, Australia, 14-16 February 2008.     

An approach based on diffusion to study ligand-macromolecule interaction

A new approach has been developed to study binding of a ligand to a macromolecule based on the diffusion process. In terms of the Fick's first law, the concentration of free ligand in the presence of a protein can be determined by the measurement of those ligands which are diffused out. This method is applied to the study of binding of methyl-orange to lysozyme in phosphate buffer of pH 6.2, at 30 degrees C. The binding isotherm was determined initially, followed by application of the Hill equation to the data obtained, then binding constant and binding capacity were estimated.     

A thermodynamic approach to PCR primer design

We developed a primer design method, Pythia, in which state of the art DNA binding affinity computations are directly integrated into the primer design process. We use chemical reaction equilibrium analysis to integrate multiple binding energy calculations into a conservative measure of polymerase chain reaction (PCR) efficiency, and a precomputed index on genomic sequences to evaluate primer specificity. We show that Pythia can design primers with success rates comparable with those of current methods, but yields much higher coverage in difficult genomic regions. For example, in RepeatMasked sequences in the human genome, Pythia achieved a median coverage of 89% as compared with a median coverage of 51% for Primer3. For parameter settings yielding sensitivities of 81%, our method has a recall of 97%, compared with the Primer3 recall of 48%. Because our primer design approach is based on the chemistry of DNA interactions, it has fewer and more physically meaningful parameters than current methods, and is therefore easier to adjust to specific experimental requirements. Our software is freely available at http://pythia.sourceforge.net.     

A thermodynamic approach to alamethicin pore formation

The structure and energetics of alamethicin Rf30 monomer to nonamer in cylindrical pores of 5 to 11 Å radius are investigated using molecular dynamics simulations in an implicit membrane model that includes the free energy cost of acyl chain hydrophobic area exposure. Stable, low energy pores are obtained for certain combinations of radius and oligomeric number. The trimer and the tetramer formed 6 Å pores that appear closed while the larger oligomers formed open pores at their optimal radius. The hexamer in an 8 Å pore and the octamer in an 11 Å pore give the lowest effective energy per monomer. However, all oligomers beyond the pentamer have comparable energies, consistent with the observation of multiple conductance levels. The results are consistent with the widely accepted “barrel-stave” model. The N terminal portion of the molecule exhibits smaller tilt with respect to the membrane normal than the C terminal portion, resulting in a pore shape that is a hybrid between a funnel and an hourglass. Transmembrane voltage has little effect on the structure of the oligomers but enhances or decreases their stability depending on its orientation. Antiparallel bundles are lower in energy than the commonly accepted parallel ones and could be present under certain experimental conditions. Dry aggregates (without an aqueous pore) have lower average effective energy than the corresponding aggregates in a pore, suggesting that alamethicin pores may be excited states that are stabilized in part by voltage and in part by the ion flow itself.     

An elementary approach to cell cycle analysis

An elementary semistochastic model for cell cycle analysis is presented. Various independently generated experimental data sets are compared with the theory in which for the first time, a consistent consideration of non-proliferating cells has also been taken into account.     

An elementary approach to cell cycle analysis

An elementary semistochastic model for cell cycle analysis is presented. Various independently generated experimental data sets are compared with the theory in which for the first time, a consistent consideration of non-proliferating cells has also been taken into account.     

An approach to minirhizotron root image analysis

Minirhizotrons speed up research on root demography, but image quality often hampers standardization of the image processing method. A simple procedure working on the blue band of colour images was tested on fibrous roots of sugarbeet (Beta vulgaris var. saccharifera). With respect to green and red, the blue band allows better detection of roots when their luminance is very similar to that of the background. The method makes use of an exponential algorithm of contrast stretching, which takes luminance frequency distribution into account. Based on a single threshold level, the procedure includes skeletonization. A minimum segment length was adopted to discriminate roots from extraneous objects. Although a specific minimum root length (MRL) value was calculated for each soil type, results show that a single value can be applied, indicating that this method can be profitably used for processing large samples of images. This revised version was published online in June 2006 with corrections to the Cover Date.     

An ecological approach to birdstrike risk analysis

Airports are peculiar developed habitats that, besides being extremely noisy and unappealing to some bird species, are highly attractive to others. Bird–aircraft collisions, or birdstrikes, cause losses in terms of human lives, direct monetary losses and associated costs for the civil aviation industry. In recent years, birdstrike risk assessment studies have focused on the economical aspects of the damage caused by wild animals and the hazards of wildlife–aircraft collisions, while an ecological approach, taking into account animal behaviour for the analysis of such events, has seldom been adopted. We conducted a risk analysis for birdstrikes at the Venice Marco Polo International Airport (VCE), Italy. We defined the key variables involved in these events and summarised their interactions in a single metric risk index we called the “Birdstrike Risk Index” (BRI). Our aim was to provide a tool for birdstrike risk analysis that described the risk on the basis of the actual presence of birds at airports. The application of the BRI at VCE allows relative risks across species to be defined, providing information for prioritising management actions. Furthermore, due to the seasonality of bird species presences, the application of the BRI to a long-term data series should give clues of birdstrike risk in future scenarios. This new ecological approach that we applied to a particular airport could easily be adapted for use at other airports worldwide and integrated into risk assessment procedures. The study results and the BRI tool are addressed to scientific consultants of airport safety managers.