Locomotor pattern generation in the spinal cord: Studies in adult lamprey and zebrafish

The overall objective of this thesis is to characterize the mechanisms involved in the generation of locomotor activity in the spinal cord. To this end, we initially used the lamprey spinal cord to determine the transmitter phenotype of commissural interneurons (CINs). In addition, we developed a novel preparation of the brainstem-spinal cord of the adult zebrafish and used it to determine the mechanisms of locomotor pattern generation. The results obtained show: (1) That the left–right alternation is maintained because commissural glycinergic interneurons outnumber the glutamatergic ones. It was also shown that CINs display a graded rostrocaudal distribution and are immunoreactive to both glycine and glutamate. The difference in the proportion of inhibitory and excitatory CINs represents an anatomical substrate that ensures the predominance of alternating activity during locomotion. (2) That adult zebrafish spinal cord can produce locomotor activity and be used to study the organization of the locomotor circuitry. In this study we developed both a semi-intact and an in vitro preparation of the juvenile/adult zebrafish spinal cord that are able to generate a rhythmic motor pattern with characteristics similar to swimming in intact animals. In the in vitro preparation, spinal cord neurons were accessible for patch-clamp recordings to study their pattern of activation during fictive locomotion. (3) That 5-HT is released within the locomotor circuitry and acts as an intrinsic modulator to set the baseline locomotor activity. 5-HT decreases the frequency of the locomotor rhythm by increasing the mid-cycle inhibition and delaying the onset of the following onphase excitation. Thus endogenous 5-HT sets the balance between excitation and inhibition and set the baseline locomotor frequency. (4) That a brief stimulation of descending inputs at a defined region located at the first segments of the spinal cord induces long-lasting coordinated swimming activity. The burst amplitude, frequency and duration of the episode can increase by changing the frequency and strength of the stimulus pulses. The descending inputs seems to act as a switch to turn on the activity of the spinal locomotor network in the caudal spinal cord that relies mostly on iontropic glutamate receptors. In summary, our results provide anatomical evidence underlying the dominance of reciprocal inhibition over excitation during locomotion. We also showed that our newly developed in vitro adult zebrafish spinal cord preparation can be used to study spinal circuitry underlying locomotion

Thermodynamic and Kinetic Investigation of Desalination by Refrigerant Clathrate Hydrate Formation

Gas hydrate is a crystalline solid compound form of water with hydrophobic gas at certain conditions (pressure and temperature). The hydrogen bond in water molecules constructs a framework as a host that entraps gas molecules (gust). Gas hydrate can be applied to many industries such as gas separation, cool storage, food concentration and desalination. Hydrate route looks a promising alternative technology compared to the conventional process, by utilizing a proper gas host, which can be held within water cavities composed by hydrogen-bonded water molecules. In this study the selected host gas was Refrigerant R134a, the work consists of an experimental and theoretical investigation dealing with hydrate formation for the ternary system (water, refrigerant gas, salt) at different initial pressures, the salts were NaCl, KBr and NaF. Method of isochoric pressure search method was used to measure the pressure and temperature for hydrate formation and conduction the three phases of (hydrate-liquid-vapour). The measurements were performed with pressure range (0.1 - 0.4) MPa and the temperatures about (275.2 – 283)K at the concentrations of (0.09,0.17 and 0.26)mol/kg for each salt. The kinetics of R134a clathrate formation for ternary systems (R134a, water and salt) at various types and concentrations of salts. Many objective functions were obtained from the kinetic model for hydrate formation, such as the amount of gas consumed, the growth rate, and the conversion of the water to hydrate. The results showed the effect of the initial pressure on the gas consumed, the rate of growth and water to hydrate conversion, that when the initial pressure increase the moles of R134a gas consumed was increased due to the increased driving force of hydrate formation, also other functions were increased. While the increasing in the concentration of salt for all types will be decreased gas consumed, whereas water to hydrate conversion, the growth rate is slightly decreased. And from the results noticed the presence of different salts in the ternary systems have an effect on the thermodynamics inhibition of refrigerant hydrates and the inhibition increases with the presence of NaCl salt in the ternary system more than other types of salt and also increases with increase the concentration of salt

Crystallinity Improvement of Co3O4 by Adding Thiourea

Tricobalt tetraoxide (Co3O4) samples having different thiourea/Co molar ratio of 0, 5 and 10 were prepared by wet chemical synthesis. The effects of thiourea content on the crystal structure-related parameters of Co3O4 were determined. The increase in the amount of thiourea caused a gradual decrease in the lattice parameters and specific surface area and an increase in the crystallinity and crystallite size. The experimental analysis results showed that thiourea content can be used to control the crystal structure-related parameters of Co3O4

Towards Security and Balance in Email Through Correspondence Negotiation

Email has emerged as a preferred communication medium among people of all generations. With the increasing number of users, SPAM has become a major cause of concern. Spammers are taking advantage of vulnerability of the email transport and delivery protocol (SMTP), to spread viruses, send fraudulent messages, etc. Consequently, the current email system suffers from lack of security, and imbalance between senders and receivers. This work introduces Correspondence Negotiation Protocol (CNP) to make email communication more secure. We address the current imbalance between senders and receivers, and try to solve this imbalance by providing more control to recipients and making senders more accountable. We present an implementation of Correspondence Negotiation Agent (CNA) - an email client that supports CNP. CNA is composed of three principal components: Authenticator, Negotiator, and esecretary. It has been implemented by extending JMail. CNA runs on multiple operating systems and can inter-operate with other email clients

The use of iron and steel industrial wastes in wastewater treatment

The Abstract is currently unavailable, due to the thesis being under Embargo

Effect Of Initial Pressure Upon Laminar Burning Velocity Of Methane-AirMixtures

The effect of the initial pressure upon the laminar flame speed, for a methane-air mixtures, has been detected paractically, for a wide range of equivalence ratio. In this work, a measurement system is designed in order to measure the laminar flame speed using a constant volume method with a thermocouples technique. The laminar burning velocity is measured, by using the density ratio method. The comparison of the present work results and the previous ones show good agreement between them. This indicates that the measurements and the calculations employed in the present work are successful and precise

A Framework for Automated Security Testing of Android Applications on the Cloud

App markets are stirring a paradigm shift in the way software is provisioned to the end users. The benefits of this model are plenty, including the ability to rapidly and effectively acquire, introduce, maintain, and enhance softwar

A Whitebox Approach for Automated Security Testing of Android Applications on the Cloud

Abstract — By changing the way software is delivered to endusers, markets for mobile apps create a false sense of security: apps are downloaded from a market that can potentially be regulated. In practice, this is far from truth and instead, there has been evidence that security is not one of the primary design tenets for the mobile app stores. Recent studies have indicated mobile markets are harboring apps that are either malicious or vulnerable leading to compromises of millions of devices. The key technical obstacle for the organizations overseeing these markets is the lack of practical and automated mechanisms to assess the security of mobile apps, given that thousands of apps are added and updated on a daily basis. In this paper, we provide an overview of a multi-faceted project targeted at automatically testing the security and robustness of Android apps in a scalable manner. We describe an Android-specific program analysis technique capable of generating a large number of test cases for fuzzing an app, as well as a test bed that given the generated test cases, executes them in parallel on numerous emulated Androids running on the cloud. Keywords-Android; Security Testing; Program Analysis I

ISLAMIC IDENTITY IN TURKEY'S ORIENTATIONS TOWARDS THE EUROPEAN UNION 1992-2004 A.D

Turkey's membership in the European Union is one of the most historical and decisive events in the construction of the social, economic and political structure of Europe. It is clear that Turkey is not a strong candidate like the others. Turkey is challenging the European system in order to be a part of it. Ironically, this challenge is as much cultural as it is political for Europe, which is more and more preoccupied with its identity, its borders, and its future. The opening of membership negotiations has alarmed the Europeans, prompting intense and unprecedented debates within the corridors of the European Parliament. The Muslim Turks, on the threshold of the European Union, are once again being imagined by turning back to Ottoman history and memory. Although EU membership is a political issue. But in the case of Turkey, discussions show that he is beyond politics. It seems that the Europeans are convinced that Turkey is a mirror of the cultural and religious heritage of Europe, and this has sparked an existential reflection on nature and identity thanks to its close interest and active presence at the local and European levels. European Christian churches are among the actors most participating in these discussions in a highly secular Europe Since religion should have nothing to do with politics, what kind of position or role should churches assume? Has religion returned to the new Europe? This paper aims to look at how "Christian Europe", which has historically led the hostile response to Muslim Turks, is now in a position to integrate Muslim Turkey into the European Union