651 research outputs found

    A Developmentally Regulated Deletion Element with Long Terminal Repeats Has \u3cem\u3eCis\u3c/em\u3e-Acting Sequences in the Flanking DNA

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    Approximately 6000 specific DNA deletion events occur during development of the somatic macronucleus of the ciliate Tetrahymena. The eliminated Tlr1 element is 13 kb or more in length and has an 825 bp inverted repeat near the rearrangement junctions. A functional analysis of the cis-acting sequences required for Tlr1 rearrangement was performed. A construct consisting of the entire inverted repeat and several hundred base pairs of flanking DNA on each side was rearranged accurately in vivo and displayed junctional variability similar to the chromosomal Tlr1 rearrangement. Thus, 11 kb or more of internal element DNA is not required in cis for DNA rearrangement. A second construct with only 51 bp of Tetrahymena DNA flanking the right junction underwent aberrant rearrangement. Thus, a signal for determination of the Tlr1 junction is located in the flanking DNA, 51 bp or more from the right junction. Within the Tlr1 inverted repeat are 19 bp tandem repeats. A construct with the 19mer repeat region deleted from the right half of the inverted repeat utilized normal rearrangement junctions. Thus, despite its transposon-like structure, Tlr1 is similar to other DNA rearrangements in Tetrahymena in possessing cis-acting sequences outside the deleted DNA

    Pathological Gambling : A Comprehensive Review

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    Due to recent changes of gambling laws, accessibility to gambling has become more widespread and thus, there has also been an increase in the prevalence of pathological gambling (PG). The wide range of social, economic, and psychological problems associated with PG are well known. There is a need for better understanding of PG and this review attempts to do so. Literature searches using the Medline and PsycINFO databases were used. Critical examining of the literature showed that familial/genetic, sociological, and individual factors (e.g., an individual's personality, biochemistry, psychological states, and cognitions) are implicated in the development and maintenance of PG, yet at present, the evidences are not solid. Similarly, there have been a lot of theories for PG but again, none of them are solid enough to provide a clear understanding of PG. Recent psychological-based theories seem to provide some solid ground for further research. We highlight four areas for future consideration for research. (1) Most studies have generalized findings from one form of gambling to another. It is suggested that it is now not tenable to consider gambling as a single phenomenon that can explain all forms of gambling. (2) Almost all of the studies in the gambling literature are Western-based and the results are often generalized to other ethnic and cultural groups. There is now an urgent need to close this gap. (3) Future studies need to address methodological problems in the current gambling/PG literature. (4) Almost all of the gambling literature has focused on the issue of why people start gambling. It is suggested that looking at variables as to why people stop gambling in a single episode may be a more fruitful area of research then why people start gambling. This is because what motivates one to continue gambling, despite losses in a session and across sessions, is a characteristic that distinguishes nonproblem gamblers from problem gamblers and pathological gamblers (PGs)

    Development and in-vitro evaluation of an optimized carvedilol transdermal therapeutic system using experimental design approach

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    AbstractThe effect of formulation variables on in-vitro release and permeation properties of carvedilol from transdermal patch was studied by varying one factor at a time as preliminary study. Based on these results, design of experiments technique was applied followed by regression analysis and response surface methodology to optimize formulation variables. Central Composite IV model design was used with four formulation variables: drug loading, matrix thickness, adhesive layer thickness, and propylene glycol concentration. Nineteen formulations were prepared according to the design; and the effect of formulation variables was studied on in-vitro release and permeation profiles of these formulations. In all cases, the permeation profiles paralleled in-vitro release profiles. The drug released at 7 h and 24 h was used as release response parameters while permeation flux obtained was employed as permeation response parameter. All four formulation variables were found to be significant for release properties and three of these exhibited significant effect on permeation profile of carvedilol across artificial membrane. Constrained optimization, using 47.9% of cumulative carvedilol released at 7 h and 99.8% at 24 h as well as 25.7 μg/cm2/h of permeation flux, was applied to obtain desired release and permeation profiles. Experimentally, carvedilol was observed to release from the optimized formulation with 51.4% drug release at 7 h and 98.5% at 24 h with an observed flux value of 27.4 μg/cm2/h across artificial membrane, which showed an excellent agreement with the predicted values. The results of this investigation show that the quadratic mathematical model developed could be used to further predict formulations with desirable release and permeation properties

    Biosynthesis of Zinc oxide Nanoparticles using Barringtonia acutangula Flower Extract and Evaluation of their Antibacterial and Antioxidant Activities

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    Zinc oxide (ZnO) has broad applications in various areas. Nanoparticle synthesis using plants is an alternative to conventional physical and chemical methods. It is known that the biological synthesis of nanoparticles is gaining importance due to its simplicity, eco-friendliness and extensive antimicrobial activity. Also, in this study we report the synthesis of ZnO nanoparticles (ZnONPs) using Barringtonia acutangula   flower extract. The prepared ZnO nanoparticles have been characterized by UV–Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM)). The antioxidant activity of the nanoparticles was tested by the α-diphenyl-β-picrylhydrazyl (DPPH) method. Antibacterial properties of the synthesized ZnONPs were evaluated against Staphylococcus aureus and Escherichia coli by disc diffusion method

    A Review-Botnet Detection and Suppression in Clouds

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    Internet security problems remain a major challenge with many security concerns such as Internet worms, spam, and phishing attacks. Botnets is well-organized distributed network attacks, consist of a large number of bots that generate huge volumes of spam or launch Distributed Denial of Service (DDoS) attacks on victim hosts. Botnet attacks degrade the status of Internet security. Clouds provide botmaster with an ideal environment of rich computing resources where it can easily deploy or remove C&C server and perform attacks.  It is of vital importance for cloud service providers to detect botnet,  prevent attack,  and trace back to the botmaster.  It also becomes necessary to detect and suppress these bots to protect the clouds. This paper provides the various botnet detection techniques and the comparison of various botnet detection techniques. It also provides the botnet suppression technique in cloud. Keywords: Cloud computing, network security, botnet, botmmaster, botnet detection, botnet suppressio

    A Review on Implementation of Real Time Image Processing for a Human Eye Computer Interaction System

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    People with physical disabilities cannot fully enjoy the benefits provided by computer System .This is because the conventional mouse and keyboard were designed to be used by those who are able bodied. Due to reducing the communication barriers between man and machine human eye computer interaction is important. The main aim of this proposed system is to design and implement a human computer interaction system that tracks the direction of the human gaze. The pupil detection and tracking is an important step for developing a human-computer interaction system. To identify the gaze direction of the user’s eye (right, left, up and down). Human eye uses contactless type devices. This work can develop a human computer interaction system that is based on iris tracking. The iris is widely used as the starting point for detection and tracking. It is an important eye feature that is circular in shape and that can be detected easily
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