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Screening for RB1 Gene Alleles in Saudi Retinoblastoma Patients
No full textRetinoblastoma (Rb) is the most common intraocular tumor which
occurs in infantile retina and may result from germ-line or somatic mutation.
In Saudi Arabia, Rb is diagnosed at an incidence of approximately 25
cases every year. However, there is no information on the nature of mutations
in the RB1 gene.
The major aim of this study was to identify germ line mutations in the
RB1 gene in Saudi Rb patients by sequencing the entire RB1 gene. The study
was conducted on 20 Rb patients and 20 normal healthy controls. In addition,
7 affected tissue and normal tissue samples were obtained from the same
patients. The demographic data of each patient and control were recorded.
Blood was used to extract DNA, and following polymerase chain reaction, the
27 exons of the RB1 gene were sequenced. Multiplex Ligation-dependent
Probe Amplification (MLPA) studies were carried out to search for long
deletions in the patients and control.
Mutations were identified in 11/20 (55%) of the patients in the germ line
and somatic cell DNA. In the germ line DNA the mutations identified were in
exons 3, 4, 5, 18 and 19. These included small deletions resulting in
frameshift (in exon 3: c.373delG; in exon 4: c.409delG; in exon 5: 504-
505delAT), base substitutions resulting in nonsense mutation and producing
premature termination (in exon 18: c.1735C>T, p.R579X), and a point
mutation resulting in substitution of an amino acid (c.1862G>A, p.R621H). A
silent mutation was also identified (c.1917G>A). Five patients had large
deletions. One of these has deletion of exons 6-9 and four patients had exon
24-26 deletions. The patients in whom RB1 mutation was not identified may
be having a large deletion which could not be identified during sequencing.
In the somatic cell DNA (from the tissue), the mutations identified were
nonsense mutations resulting in premature termination (in exon 8: c.751C>T,
p.R251X and in exon 14: c.1363C>T, p.R455X) small deletions (in exon 5:
504-505delAT); and a large deletion of exons 24-26. A silent mutation was
also identified in the normal tissue. Of these mutations four were novel
mutations and further studies are necessary to identify their effect on the
functional aspects of the resultant Rb protein (pRb).
In the intronic regions sequenced, ten single nucleotide polymorphisms
(SNPs) were identified. These were in the introns 1, 2, 3, 4, 25 and 26. Two of
the SNPs associated significantly with retinoblastoma. rs2252544 in intron 1,
showed a statistically significant difference in the genotype frequency in the
Rb patients and controls (p<0.05), while rs1981434 also in the intron 1
showed a highly significant (p<0.0001) difference in both the genotype and
allele frequencies.
In conclusion, sequencing was considered as an effective though expensive
method for screening. It is suggested that there is a need to develop such
screening methods that will identify the mutation without screening the entire
gene in each Rb patient. Further studies are warranted to have a more clear
view of RB1 mutations involved in Rb development in Saudis
Adding a Dalaunay ends to a compact or a complete noncompact con- stant mean curvature hypersurface
No full textStarting from a compact or a complete noncompact constant mean cur- vature hypersurface with k ends asymptotic to Delaunay hypersurfaces we construct in this paper a new constant mean curvature hypersurface with k + m ends which is obtained by performing a connected sum of m additional Delaunay ends of small Delauany parameters at some m points p 1, . . . , p m of the initial hypersurfac
Construction of compact constant mean curvature hypersurfaces with topology
No full textIn this paper, we explain how the end-to-end construction together with
the moduli space theory can be used to produce compact constant mean curvature hypersurfaces with nontrivial topology. For the sake of simplicity, the hypersurfaces we construct have a large group of symmetry but the method can certainly be used to provide many more examples with less symmetrie
نموذج مقترح لبيئة تعلّم إلكترونية للتعلّم الجوّال في جامعة الملك سعود في ضوء معايير التعلّم الجوّال "
No full textهدفت هذه الدراسة إلى اقتراح نموذج لبيئة تعلّم إلكترونية للتعلّم الجوّال في جامعة الملك سعود. وقد استخدم الباحث أسلوب دلفي لتحقيق هذا الهدف، حيث تكون مجتمع الدراسة وعينتها من مجموعة من الخبراء في مجال تكنولوجيا المعلومات، وتكنولوجيا التعليم، وعددهم (20) خبيراً، في جامعات المملكة العربية السعودية، والجامعات الأردنية. تمّ استخدام المنهج الوصفي التحليلي لمناسبته موضوع الدراسة.
وقد أسفرت الدراسة عن عدة نتائج، من أهمها:
1. تحديد المعايير التربوية في بيئة التعلم الجوّال.
2. التعرف على المعايير التقنية في بيئة العلم الجوّال.
3. تحديد ملامح النموذج المقترح لبيئة التعلم الجوّال لجامعة الملك سعود.
وفي ضوء النتائج أوصى الباحث بما يلي:
1.أن تعتمد جامعة الملك سعود هذه البيئة المقترحة للتعلم الجوّال؛ لمناسبتها الوضع الاجتماعي للمرأة في المملكة.
2. أن تأخذ إدارة الجامعة على عاتقها القيام بعدة أمور قبل تطبيق هذا النموذج، منها: تحويل المقررات الحالية إلى مقررات رقمية، ونشر ثقافة التعلم الإلكتروني بين أعضاء هيئة التدريس والطلبة، رصد الميزانية اللازمة لتطبيق هذا النموذج.
3. أن تقوم إدارة الجامعة بإجراء دراسات تشمل: تقويم تطبيق هذا النموذج، واتجاهات أعضاء هيئة التدريس والطلبة نحوه، والعقبات التي تواجه تطبيقه
Determination of the hole mobility and effective Hall factor of
No full textHole mobility and effective Hall factor for p-type GaSb were studied theoretically as a function of temperature from 10K up to 300K. The mobility calculations were based on the relaxation time approximation
taking into account elastic scattering mechanisms including lattice and ionized-impurity types. The results showed that the ionized-impurity scattering is the dominant mechanism at low-temperature range while lattice scattering may be the dominant one at higher temperatures. The effective Hall factor was investigated using the two-band model assuming parabolic valence bands. Hall parameters of p-GaSb were analyzed by assuming that the bands of heavy and light holes are decoupled. If the impurity scattering exceeds all other scattering processes, the effective Hall factor may tend to unity but when the lattice scattering process dominates, this approximation is not valid
Gas holdup in circulating bubble columns with pseudoplastic liquids
No full textThe contributions of pressure drop due to wall frictional losses to the total gas holdup of two-phase viscous non-Newtonian systems were experimentally investigated using a 150 dm3 circulating bubble column. The column had a downcomer-to-riser cross-sectional area ratio of 0.54 and a dispersion height of 2.5 m. Aqueous solutions of xanthan gum and carboxymethyl cellulose were used to simulate a wide range of rheological properties. The average wall shear stress was estimated from Al-Masry's (1999) correlation for the average wall shear rate in external loop airlift reactors. Pressure drop due to wall shear stress was found significantly contributed by 10-70% to the total gas holdup. This contribution has always been ignored in the data presented in the literature due to the absence of reliable and simple correlations for the average shear rate and shear stress. Corrections to gas holdup were found necessary for non-Newtonian solutions with concentrations of ≥ 0.5 wt/wt.-%
On the QoS behavior of self-similar traffic in a converged ONU-BS under custom queueing
No full textA novel converged ONU-BS architecture has been contemplated
for next-generation optical-wireless networks. It has been demonstrated through high quality studies that data traffic carried by both wired and wireless networks exhibit self-similar and long range dependent characteristics; attributes that classical teletraffic theory based on simplistic Poisson models fail to capture.
Therefore, in order to apprehend the proposed converged architecture and to reinforce the provisioning of tightly bound QoS parameters to end-users, we substantiate the analysis of the QoS behavior of the ONU-BS under self-similar and long range dependent traffic conditions using custom queuing (CQ) which is a common queuing discipline. This paper extends our previous work on priority queuing (PQ) and brings novelty in terms of presenting performance analysis of the converged ONU-BS under realistic traffic load conditions. Further, the presented analysis can be used as a network planning and optimization tool to select the most robust and appropriate queuing discipline for the ONU-BS relevant to the QoS requirements of different applications
Agent-based approach semantic web services personalization
No full textIn the last few years, Semantic Web Community proposes standards and semantic representations of the Web Services, DAML-S and OWL-S are two standards examples of semantic representations of web services that are used in the last few years. These standards are ontologies that support web services depending on DAML markup language standard. Traditional personalization of these web services is a problem. Because personal (user) information is hardly utilized to make the interaction with the user context more efficient for satisfying user needs. Nowadays many efforts are done to personalize the web service and the semantic web services (SWS). These efforts allow adding user context as a part of the web service description. The cornerstone of SWS is the Matchmaker/Broker agent, which hardly utilizes the user context and the personal needs in the web service. In this work, the Multi-agent Personalization of the SWS (MPSWS) approach is introduced. In MPSWS, both user information and SWS are interactively to identify user needs. The aim of this research is to present an efficient interaction way between two technologies, namely personal producing (user agents) systems and personal consumer (SWS) systems. This approach supports and realizes the personalization in the interaction between the user itself and the SWS. This research explores how agent-based systems can support the interaction between users and semantic web services in a dynamic configuration and social settings characteristics. More specifically, our work aims to advances the following contributions: (1)proposing a system architecture that supports personalization in the semantic web services; (2)applying an efficient problem solvers based on the user’s context to determine his/her intentions; (3)applying an efficient machine learning mechanism to ‘automatically’ identify user intensions from the history events; (4) building personal OWLS queries, which are processed by SWS matchmaker, to identifying semantic web services that support user needs; (5) applying an efficient mechanism to manipulate the matchmaker results (i.e. user needs) and to provide them to the user
A New Similarity Measure for the Profiles Management
No full textThe measure of similarity is necessary for the study of several problems such as: the multimedia adaptation, detection of intrusion based behavior, adaptation of web services …. In this article, the definition of a new measure of similarity that deals with the shared objects properties, their values and the weight of each property is proposed
Al-Baseet: A proposed simplification authoring tool for the Arabic language
No full textThis paper sheds the light on the importance of developing an Arabic simplification tool for the benefit of Arabic readers with low levels of literacy and for Arabic learners. We propose a prototype for a simplification tool, called Al-Baseet, in which we identify some basic modules and stages that are necessary for performing automatic Arabic text simplification. The limitations that stand in the way of developing such a tool are then investigated and recommended for further research