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

Implementation of Quality Management System in Iranian Medical Laboratories

"nReference health Laboratory of Iran (RHL) has been established under the Secretary of Health in 2007. This organization has been developed from integration of Reference laboratories of Iran, Directorate of General Affairs and Laboratory de­partment of CDC. In accordance with policies of Ministry of Health and Medical Education, also Millennium Development Goals and requirements of IHR the RHL has highlighted his main goal as "Quality Improvement of Medical Laboratory Net­work". In order to achieve this goal as soon and efficient as possible, RHL has tried to launch Quality Management sys­tem in medical laboratories. After studying and analyzing the situation in the country RHL has tried by using ISO 15189 which is an successful international standard to draw national standards and write necessary manuals, guidelines and check­lists. For a successful implementation and detailed managerial observance, three phases were designed: Training, Stepwise imple­mentation of standard requirements in the laboratories, accreditation of laboratories. After one year of training and send­ing out national standards and guidelines, the RHL is in the middle of the second phase "implementation"

Clostridium difficile infection: A review

Clostridium difficile, as one of the main bacterial causes of diarrhea, is an important healthcare-associated pathogen. It is also the main causative agent of antibiotic-associated diarrhea and pseudomembranous colitis. The C. difficile infection is a life threatening disease, and there is an urgent need to control its spread in healthcare centers. This review summarizes the most recent work on epidemiology and interactions between host and C. difficile. © 2018 Wolters Kluwer Health, Inc

Physical and photophysical characterization of a BODIPY phosphatidylcholine as a membrane probe.

Lipids containing the dimethyl BODIPY fluorophore are used in cell biology because their fluorescence properties change with fluorophore concentration (C.-S. Chen, O. C. Martin, and R. E. Pagano. 1997. Biophys J. 72:37-50). The miscibility and steady-state fluorescence behavior of one such lipid, 1-palmitoyl-2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-sn-glycero-3-phosphocholine (PBPC), have been characterized in mixtures with 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC). PBPC packs similarly to phosphatidylcholines having a cis-unsaturated acyl chain and mixes nearly ideally with SOPC, apparently without fluorophore-fluorophore aggregation. Increasing PBPC mole fraction from 0.0 to 1.0 in SOPC membranes changes the emission characteristics of the probe in a continuous manner. Analysis of these changes shows that emission from the excited dimethyl BODIPY monomer self quenches with a critical radius of 25.9 A. Fluorophores sufficiently close (< or =13.7 A) at the time of excitation can form an excited dimer, emission from which depends strongly on total lipid packing density. Overall, the data show that PBPC is a reasonable physical substitute for other phosphatidylcholines in fluid membranes. Knowledge of PBPC fluorescence in lipid monolayers has been exploited to determine the two-dimensional concentration of SOPC in unilamellar, bilayer membranes

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

SUPERPAVE design mixture performance evaluation using Epolene modifier for cold semi-arid climatic region of Saudi Arabia

Purpose: To evaluate the superpave design performance using Epolene (EE-2) as modifier, since SUPERPAVE design is a modified and sophisticated aspect as compared to previous mix design for asphalt mixtures. This is primarily due to the fact that superpave design mix also takes into consideration properties of materials beside asphalt. Design/methodology/approach: This study was conducted using Epolene (EE-2) as modifier in order to evaluate the performance of SUPERPAVE suitability for construction of roads in Alfaraa campus (King Khalid University) Abha, in Asir Province of Saudi Arabia. Glow number test, dynamic modulus test and indirect tensile strength test were conducted to evaluate the performance of EE-2 modifier against the control mixture. Findings: The mixture modified with EE-2 gave better performance in terms of temperature-based performance and resistance to moisture damage. Also, larger values of E*/sinφ were obtained for EE-2 modified mixture at various loading frequencies and temperature in comparison to control mixture. Research limitations/implications: The Epolene modifier successfully enhances and improves the SUPERPAVE mixture performance. Further studies are required to evaluate the performance of EE-2 modifier at much lower temperature ranges. Practical implications: The results of the study allow us to recommend the investigated asphalt mixture for applied for the construction of roads in the Alfaraa (new campus of King Khalid University), Abha, Asir province, Saudi Arabia. Originality/value: A modified asphalt mixture has been proposed that has better performance at higher and lower temperatures. The developed asphalt mixture is more resistant to moisture damage than the compared to control mixture