Impedance Analysis of Complex Formation Equilibria in Phosphatidylcholine Bilayers Containing Decanoic Acid or Decylamine

Bilayer lipid membranes composed of phosphatidylcholine and decanoic acid or phosphatidylcholine and decylamine were investigated using electrochemical impedance spectroscopy. Interaction between membrane components causes significant deviations from the additivity rule. Area, capacitance, and stability constant values for the complexes were calculated based on the model assuming 1:1 stoichiometry, and the model was validated by comparison of these values to experimental results. We established that phosphatidylcholine and decylamine form highly stable 1:1 complexes. In the case of decanoic acid-modified phosphatidylcholine membranes, complexes with stoichiometries other than 1:1 should be taken into consideration

Challenges and opportunities in development sustainable transportation system in Saudi Arabia

This paper presents the recent development of transportation system in Saudi Arabia. Review of transportation system developed in the last three decades including air, land, sea and rail transportation. Problems raised from each mode of transportation were addressed and possible solution were provided. The results indicate that air transportation could provide the necessary needs of the Kingdom of Saudi Arabia in international connections while domestic air transportation provide limited passenger transportation for relatively long distances. This mode is limited to high income people and cannot serve short distances in effective way. Sea transportation could provide the country with freight transport but limited to passengers only in the Golf region or in the red see with some African countries. Road and highway provide the most transportation used by the public but associated with several problems such as environmental pollution, large number of road traffic accident and became the first cause of death in the Kingdom. Bus and car public transportation need essential improvement to meet the demand and save transportation for the public. Rail transportation seems to be the most sustainable transportation in future transportation in the country. Saudi Arabia late pay attention to rail transportation and recently intensive budget invested in rail transportation. Further development in rail transportation in the Kingdom is needed

Quality Assurance Program for Molecular Medicine Laboratories

Background: Molecular diagnostic methods have played and continuing to have a critical role in clinical laboratories in recent years. Therefore, standardization is an evolutionary process that needs to be upgrade with increasing scientific knowledge, improvement of the instruments and techniques. The aim of this study was to design a quality assurance program in order to have similar conditions for all medical laboratories engaging with molecular tests.Methods: We had to design a plan for all four elements; required space conditions, equipments, training, and basic guidelines. Necessary guidelines was prepared and confirmed by the launched specific committee at the Health Reference Laboratory.Results: Several workshops were also held for medical laboratories directors and staffs, quality control manager of molecular companies, directors and nominees from universities. Accreditation of equipments and molecular material was followed parallel with rest of program. Now we are going to accredit medical laboratories and to evaluate the success of the program.Conclusion: Accreditation of medical laboratory will be succeeding if its basic elements are provided in advance. Professional practice guidelines, holding training and performing accreditation the molecular materials and equipments ensured us that laboratories are aware of best practices, proper interpretation, limitations of techniques, and technical issues. Now, active external auditing can improve the applied laboratory conditions toward the defined standard level

The dynamin middle domain is critical for tetramerization and higher-order self-assembly

The large multidomain GTPase dynamin self-assembles around the necks of deeply invaginated coated pits at the plasma membrane and catalyzes vesicle scission by mechanisms that are not yet completely understood. Although a structural role for the ‘middle' domain in dynamin function has been suggested, it has not been experimentally established. Furthermore, it is not clear whether this putative function pertains to dynamin structure in the unassembled state or to its higher-order self-assembly or both. Here, we demonstrate that two mutations in this domain, R361S and R399A, disrupt the tetrameric structure of dynamin in the unassembled state and impair its ability to stably bind to and nucleate higher-order self-assembly on membranes. Consequently, these mutations also impair dynamin's assembly-dependent stimulated GTPase activity