Identification and Characterisation of Herpes Simplex Virus Genes Required for Encapsidation of DNA

The aim of the study presented in this thesis was to characterise two herpes simplex virus type 1 (HSV-1) DNA positive temperature sensitive (ts) mutants, tsl233 and ts1201, and the genes in which their mutations lie. Electron microscopic examination of thin section preparations of ts1233-infected cells revealed that at the non-permissive temperature (NPT) the nuclei contained large numbers of partially-cored capsids. In contrast to wt virus-infected cells, no dense capsids or empty capsids were detected in the nuclei of ts1233-infected cells at the NPT. This result suggests that the mutant has a block in the assembly of full nucleocapsids. The effect of the ts1233 mutation could not be reversed when mutant virus-infected cells were shifted from the NPT to the permissive temperature (PT) in the presence of a protein synthesis inhibitor. Southern blot analysis of total and encapsidated DNA confirmed that ts1233 failed to encapsidate DNA at the NPT, and showed that the DNA synthesized by ts1233 at the NPT was in an endless state. This information suggested that most of the mutant DNA was in the form of high moleculer weight (mw) concatemers at the NPT. Previous work had located the ts mutation of ts1233 within EcoRI o. Complementation experiments between ts1233 and another HSV-1 mutant tsN20, which also had a lesion in HSV EcoRI o, showed that ts1233, belonged to a different cistron from fsN20. The polypeptide profile of ts1233-infected cells was similar to that of wt virus-infected cells. In contrast to the mutant ts1201, ts1233 processed the structural protein UL26 gene product normally and therefore, the gene in which ts1233 maps is not required for the processing of UL26 gene product. Marker rescue experiments localised the lesion in ts1233 within a 150bp fragment which contains the 5' ends of two genes, UL32 and UL33 oriented in opposite directions. UL32 encodes a 64,000 mw polypeptide and UL33 encodes a 14,000 mw polypeptide. The nucleotide sequence of a 392 base pair (bp) fragment from ts1233 and two ts+ revertants for growth, isolated during this study, was determined. Sequence analysis revealed that ts1233 had a single bp change at residue 69210 of HSV-1 DNA nucleotide sequence within gene UL33. The alteration resulted in the substitution of an isoleucine by an asparagine codon. The nucleotide sequence of the revertants in this region was identical to that of wt virus DNA. The nature of the mutation in ts1233 is consistent with the use of UV-light as a mutagen. Two oligopeptides, one representing a portion of the amino-terminus and the other representing a portion of the carboxy-terminus of UL33 amino acid sequence were synthesised and coupled either to bovine serum albumin (BSA) or to B-galactosidase and injected into rabbits. Antibodies against the peptides were detected by radioimmunoassays. No virus specific bands were detected when the antisera were reacted with virus infected cell extracts on western blots, however, immunoprecipitation experiments with virus-infected cell extracts and the antisera gave a very weak specific reaction with a polypeptide of the apparent mw predicted for UL33 gene product. Attempts to express the UL33 gene product in bacterial expression vectors were unsuccessful. The UL33 gene product was also placed under immediate-early (IE) gene regulation. The IE promoter and upstream regulatory sequence of Vmw175 were inserted in front of the UL33 gene and the UL33 gene containing IE promoter recombined into TK gene of tsK virus, which has a defect in Vmw175. Although novel bands were detected in cells infected with tsK recombinant virus at the NPT, further work is required to determine whether any of these bands are the UL33 gene product. Ts1201, like ts1233 fails to encapsidate DNA at the NPT. Sequence analysis of the 673bp fragment in which the ts1201 lesion mapped revealed that the mutation lies 89bp upstream from the amino terminus of UL26. A single bp change was found at a position corresponding to residue 50897 of HSV-1 11 syn+ nucleotide sequence. This resulted in the substitution of tyrosine with phenyl alanine codon. Both the ts+ revertants analys ed retained the ts1201 mutation and had second site reversions elsewhere within UL26 gene. Three oligopeptides, one representing 9 amino acids at the amino terminus of UL26, one representing 12 amino acids from the second potential AUG, and one representing 14 amino acids of the carboxy terminus were synthesised, coupled to B-galactosidase and injected into rabbits. The antisera all contained oligopeptide antibodies that recognised the peptides which they were raised against. However, in western blot experiments only antibodies against the carboxy terminus of UL26 gene product reacted with a specific virus band in virus infected cell extracts (Abstract shortened by ProQuest.)

Confidentiality as a Justification for Resorting to Arbitration in Investment Contracts Disputes

The study aimed to identify the extent of the arbitration parties' commitment to confidentiality in arbitration and to identify the extent to which the principle of confidentiality is assumed in arbitration. The study adopted the comparative analytical and descriptive method. The study reached results, the most important of which are: Confidentiality is the most important characteristic of arbitration, which makes arbitration distinct from the state’s judiciary, and that confidentiality is one of the justifications for resorting to arbitration, to preserve the commercial, industrial and technical secrets of the parties to the dispute. Confidentiality is an assumed principle in arbitration in investment contract disputes without stipulating it in the arbitration agreement. The study recommended: The arbitral institutions should confirm the extent to which the principle of confidentiality is applied in investment contract disputes in their arbitral procedures. Arbitral institutions should organize their position when justifications for transparency are achieved in the arbitral process. The contracting parties shall clarify in the arbitration agreement what is related to applying the principle of confidentiality and what is related to the application of transparency. Keywords: confidentiality, arbitration of disputes, investment contracts DOI: 10.7176/JLPG/110-13 Publication date: June 30th 202

An Improved Public Key Cryptography Based on the Elliiptic Curve

Elliptic curve cryptography offers two major benefits over RSA: more security per bit, and a suitable key size for hardware and modern communication. Thus, this results to smaller size of public key certificates, lower power requirements and smaller hardware processors. Three major approaches are used in this dissertation to enhance the elliptic curve cryptsystems: reducing the number of the elliptic curve group arithmetic operations, speeding up the underlying finite field operations and reducing the size of the transited parameters. A new addition formula in the projective coordinate is introduced, where the analysis for this formula shows that the number of multiplications over the finite field is reduced to nine general field element multiplications. Thus this reduction will speed up the computation of adding two points on the elliptic curve by 11 percent. Moreover, the new formula can be used more efficiently when it is combined with the suggested sparse elements algorithms. To speed up the underlying finite field operations, several new algorithms are introduced namely: selecting random sparse elements algorithm, finding sparse base points, sparse multiplication over polynomial basis, and sparse multiplication over normal basis. The complexity analysis shows that whenever the sparse techniques are used, the improvement rises to 33 percent compared to the standard projective coordinate formula and improvement of 38 percent compared to affine coordinate. A new algorithm to compress and decompress the sparse elements algorithms are introduced to reduce the size of the transited parameters. The enhancements are applied on three protocols and two applications. The protocols are Diffie-Hellman, ELGamal and elliptic curve digital signature. In these protocols the speed of encrypting, decrypting and signing the message are increased by 23 to 38 percent. Meanwhile, the size of the public keys are reduced by 37 to 48 percent. The improved algorithms are applied to the on-line and off-line electronic payments systems, which lead to probably the best solution to reduce the objects size and enhance the performance in both systems

Shear Strength of Reinforced Concrete Squat Walls

Squat shear walls are widely used in various structures to resist earthquake loads. However, the relevant design expressions found in building codes and literature do not incorporate the influence of all crucial parameters and provide inconsistent peak shear strength estimations. This study adopts the artificial neural network (ANN) to predict the peak shear strength of squat walls using an extensive database that includes the results of 487 walls with wide-ranging test parameters. The ANN models consider the effect of concrete strength, the wall aspect ratio, vertical and horizontal reinforcements, vertical reinforcement of boundary elements, and axial load ratio. These accurately predicted the available test results. They implemented it to carry out parametric and sensitivity analysis to investigate the effect of the main parameters on the peak strength and to give information about the factors that contribute most to the shear response. In addition, a softened strut and tie method is proposed, considering the variables that substantially influence the shear strength. A nonlinear regression analysis is employed to determine the coefficients of the proposed model using the available database. The performance of the proposed model is measured using the existing models, which results in the best favorable agreement with the test results. Doi: 10.28991/CEJ-2023-09-02-03 Full Text: PD

Integrating public relations into marketing strategies in the state of Qatar

This study investigates the prevalence of public relations in Qatar\u27s private sector and assesses the marketing manager\u27s awareness of and attitude towards public relations

Economical desalination processes in Qatar

The limited underground water resources and the dramatic increase of fresh water consumption in Qatar forced the government to seek alternative ways to compensate for the lack of fresh water resources. Unfortunately, most of the currently available alternatives are costly in terms of excessive fuel consumption; also they require large capital investment and high maintenance cost. Such plants currently produce over 98% of the total fresh water in Qatar. This ratio may increase to 100% in the next few years. The main aim of this work is to investigate the most viable water desalination processes, which can produce sufficient, and a continuous supply of fresh water with low operation and construction costs. Climatic conditions and solar radiation in Qatar have been studied and analysed to determine the performance of any potential solar system applicable to this country. A technical and economical investigation into the current and common desalination methods with particular emphasis on the three main desalination systems including multistage flash, multiple effect distillation and reverse osmosis were conducted and included. A comprehensive literature survey on various water desalination methods was undertaken. The current experimental program was confined mainly to one novel type of tilted tray solar still system, namely pyramid tilted tray solar still, which was developed to increase productivity by increasing the receiving surface area of the still (the absorber) in order to collect the optimum amount of solar radiation. Two types of cover have also been selected and tested in this work, namely pyramid and dome shapes. These tilted tray solar stills were designed and constructed on a small scale and have been tested under controlled laboratory conditions at the University of Hertfordshire. Various parameters, which are likely to effect the still performance have been investigated. These include water flow rate, spacing between cover and tray surface, glass thickness, insulation layer, and inlet water temperature. Finally, a comparison of the stills performance characteristics of the two shapes has been carried out. The laboratory experimental results of hourly production revealed that pyramid type solar still yield higher distilled water output results than the dome type. However, the use of the pyramid shape with tilted tray solar can lead to further increase in the still productivity by optimising the orientation and surface area of the still absorber. The field experimental results of pyramid solar still, which were conducted under local climate conditions of Qatar, indicated clearly that solar desalination can be a suitable economical option, particularly for remote areas, where the fresh water demand is low and water transport is expensive. Moreover, a theoretical model was employed to predict the effects on solar still performance under three various parameters under typical climatic conditions of Qatar; These include the thermal insulation layer, the water depth and wind speed. Due to the economical reasons the dual-purpose multistage flash process will remain for the foreseeable future the preferred process, when fresh water and electricity demands are growing concurrently and rapidly

The development of micropillars and two-dimensional nanocavities that incorporate an organic semiconductor thin film

Photonic crystals (PC) are periodic optical structures containing low and high refractive index layers that influence the propagation of electromagnetic waves. Photonic cavities can be created by inserting defects into a photonic crystal. Such structures have received significant attention due to their potential of confining light inside volumes (V) smaller than a cubic wavelength of light (λ/n)3 which can be used to enhance light-matter interaction. Cavity quality factor (Q) is useful for many applications that depend on the control of spontaneous emission from an emitter such quantum optical communication and low-threshold lasing. High Q/V values can also result in an enhancement of the radiative rates of an emitter placed on the surface of the cavity by means of the Purcell effect. This thesis concerns the fabrication and study of two types of optical cavity containing an organic-semiconductor material. The cavities explored are; (1) one-dimensional micropillar microcavities based on multilayer films of dielectric and organic materials, and (2) two-dimensional nanocavities defined into a photonic crystal slab. Firstly, light emission from a series of optical micropillar microcavities containing a thin fluorescent, red-emitting conjugated polymer film is investigated. The photoluminescence emission from the cavities is characterized using a Fourier imaging technique and it is shown that emission is quantised into a mode-structure resulting from both vertical and lateral optical confinement within the pillar. We show that optical-confinement effects result in a blue-shift of the fundamental mode as the pillar-diameter is reduced, with a model applied to describe the energy and distribution of the confined optical modes. Secondly, simulation, design, and analysis of two dimensional photonic crystal L3 nanocavities photonic crystal are presented. Nanocavities were then prepared from silicon nitride (SiN) as the cavity medium with the luminescence emitted from an organic material at red wavelengths that was coated on the cavity surface. To improve the quality factor of such structures, hole size, lattice constant and hole shift are systematically varied with their effect as cavity properties determined. Finite Difference Time Domain (FDTD) modelling is used to support the experimental work and predict the optimum design for such photonic crystal nanocavity devices. It is found that by fine-tuning the nearest neighbour air-holes close to the cavity edges, the cavity Q factor can be increased. As a result, we have obtained a single cavity mode having a Q-factor 938 at a wavelength of 652 nm. Here, the cavity Q factor then increases to 1100 at a wavelength of 687 nm as a result of coating a red-emitting conjugated polymer film onto the top surface of the nanocavity. We propose that this layer planarizes the dielectric surface and helps reduce optical losses as a result of scattering

Integrating public relations into marketing strategies in the state of Qatar

This study investigates the prevalence of public relations in Qatar\u27s private sector and assesses the marketing manager\u27s awareness of and attitude towards public relations

Career development in the bureaucracy of Jordan

Abstract available: p.

Reporting and methodologic quality of Cochrane Neonatal review group systematic reviews

<p>Abstract</p> <p>Background</p> <p>The Cochrane Neonatal Review Group (CNRG) has achieved a lot with limited resources in producing high quality systematic reviews to assist clinicians in evidence-based decision-making. A formal assessment of published CNRG systematic reviews has not been undertaken; we sought to provide a comprehensive assessment of the quality of systematic reviews (both methodologic and reporting quality) published in CNRG.</p> <p>Methods</p> <p>We selected a random sample of published CNRG systematic reviews. Items of the QUOROM statement were utilized to assess quality of reporting, while items and total scores of the Oxman-Guyatt Overview Quality Assessment Questionnaire (OQAQ) were used to assess methodologic quality. Two reviewers independently extracted data and assessed quality. A Student t-test was used to compare quality scores pre- and post-publication of the QUOROM statement.</p> <p>Results</p> <p>Sixty-one systematic reviews were assessed. Overall, the included reviews had good quality with minor flaws based on OQAQ total scores (mean, 4.5 [0.9]; 95% CI, 4.27–4.77). However, room for improvement was noted in some areas, such as the title, abstract reporting, a <it>priori </it>plan for heterogeneity assessment and how to handle heterogeneity in case it exists, and assessment of publication bias. In addition, reporting of agreement among reviewers, documentation of trials flow, and discussion of possible biases were addressed in the review process. Reviews published post the QUOROM statement had a significantly higher quality scores.</p> <p>Conclusion</p> <p>The systematic reviews published in the CNRG are generally of good quality with minor flaws. However, efforts should be made to improve the quality of reports. Readers must continue to assess the quality of published reports on an individual basis prior to implementing the recommendations.</p