864 research outputs found
Candidate polyanion microbicides inhibit HIV-1 infection and dissemination pathways in human cervical explants.
No full textBACKGROUND: Heterosexual intercourse remains the major route of HIV-1 transmission worldwide, with almost 5 million new infections occurring each year. Women increasingly bear a disproportionate burden of the pandemic, thus there is an urgent need to develop new strategies to reduce HIV-1 transmission that could be controlled by women themselves. The potential of topical microbicides to reduce HIV transmission across mucosal surfaces has been clearly identified, and some agents are currently under evaluation in clinical trials. Many of these "first generation" microbicides consist of polyanionic compounds designed to interfere with viral attachment. Here we have evaluated two candidate polyanion compounds in clinical trials, PRO 2000 and dextrin sulphate (DxS) to determine their safety and efficacy against in vitro HIV-1 and HSV-2 infection using cellular and tissue explant models.
RESULTS: PRO 2000 and DxS potently inhibited infection by HIV-1 X4 and R5 isolates when present during viral exposure. However PRO 2000 required 10-fold and DxS 2000-fold more compound to block infection with R5 virus than X4. While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus. PRO 2000 efficiently inhibited infection of cervical explants and dissemination of virus by migratory DC. DxS was less active, able to completely inhibit cervical explant infection, but providing only partial reduction of virus dissemination by DC. PRO 2000, but not DxS, also inhibited HIV-1 binding to DC-SIGN+ cells and trans infection of co-cultured target cells. The inflammatory potential of both compounds was screened by measurement of cytokine production from cervical explants, and statistically significant increases were only observed for IL-1beta and RANTES following treatment with PRO 2000. Both compounds also demonstrated potent activity against HSV-2 infection of cervical epithelial cells.
CONCLUSION: Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants. DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways. PRO 2000 has now entered human phase III efficacy trials
Language Engineering in Grammatical Framework (GF)
No full textThis thesis describes a number of practical experiments rather than theoreticalinvestigations in the area of natural language processing. The basis forthe work presented is Grammatical Framework (GF). It is a very complexsystem, which comprises among other things a grammar formalism based ontype theory and its implementation written in Haskell. GF is intended forhigh-quality machine translation (of INTERLINGUA type) in the restrictedlanguage domains.The primary concern of this thesis is however limited to the usage of GFas a piece of software. The main results are: Implementing a syntax editor, which provides a graphical user interface(GUI) for the command-line GF core. Writing a part of code for automatic generation of gramletspure Javaprograms with limited (compared to GF) functionality that can be runon PDA (Portable Device Assistants) and as applets in a browser. Writing the Russian resource grammar that takes care of the most basicmorphological and syntactic rules and serves as a standard libraryfor building application grammars (describing restricted language domains)in Russian.These results contribute to language engineering in GF on two differentlevels: Author level (end-user) constructing sentences in natural languages. Grammarian level building a grammar description, which is laterused on the author level.The last part of the thesis deals with a non-linguistic domain. In thatexperiment we try to apply functional parsing technique to the well-knownproblem of protein secondary structure prediction (bioinformatics)
Language Engineering in Grammatical Framework (GF)
No full textThis thesis describes a number of practical experiments rather than theoreticalinvestigations in the area of natural language processing. The basis forthe work presented is Grammatical Framework (GF). It is a very complexsystem, which comprises among other things a grammar formalism based ontype theory and its implementation written in Haskell. GF is intended forhigh-quality machine translation (of INTERLINGUA type) in the restrictedlanguage domains.The primary concern of this thesis is however limited to the usage of GFas a piece of software. The main results are: Implementing a syntax editor, which provides a graphical user interface(GUI) for the command-line GF core. Writing a part of code for automatic generation of gramletspure Javaprograms with limited (compared to GF) functionality that can be runon PDA (Portable Device Assistants) and as applets in a browser. Writing the Russian resource grammar that takes care of the most basicmorphological and syntactic rules and serves as a standard libraryfor building application grammars (describing restricted language domains)in Russian.These results contribute to language engineering in GF on two differentlevels: Author level (end-user) constructing sentences in natural languages. Grammarian level building a grammar description, which is laterused on the author level.The last part of the thesis deals with a non-linguistic domain. In thatexperiment we try to apply functional parsing technique to the well-knownproblem of protein secondary structure prediction (bioinformatics)
Language Engineering in Grammatial Framework (GF)
No full textThe basis for the work presented is Grammatical Framework (GF)a grammar
formalism based on type theory. It is also a powerful language processor
that provides a convenient framework for various multilingual applications.
The primary concern of this thesis is the usage of GF as a piece of software.
The main results are:
Implementing a syntax editor, which provides a graphical user interface
(GUI) for the command-line GF core.
Writing the Russian resource grammar that takes care of the most
basic morphological and syntactic rules and serves as a standard library
for building application grammars (describing sublanguage domains) in
Russian.
These results contribute to language engineering in GF on two different
levels:
Author level (end-user)constructing documents in natural languages.
Grammarian level building a grammar description, which is later
used on the author level. One can also distinguish between application
and resource grammars. An application grammar focuses of a particular
sub-language domain, while resource grammar is a general-purpose
grammar that forms a basis for application grammars
Internship at GoFoton GF Micro Optics Philippines, Inc.
No full textThis paper is a compilation of the internship of the author in the 1st semester of the academic year 2012-2013. It serves as a documentation of the activities that transpired in the internship of the author in GF Micro Optics Philippines, Inc. from May, 1012 until August, 2012.
Included in this paper are the company profile, experiences of the author in the company, and the tasks assigned while taking the training course. Process flow improvement was the main task of the author as his main role under the Industrial Engineering Department of GF Micro Optics Philippines, Inc.
Furthermore, the paper includes problems encountered and lessons learned by the author throughout the training course. These lessons include time management, co-worker management, task management, and enhancement of the authors whole being and skills such as problem solving. All are explained in this manuscript in order to provide self and academic evaluation of the authors training
Linear complexity profile of sequences over the field GF(Q)
No full textSummary form only given. The author extends Reuppel's concept of the linear complexity profile of binary sequences to sequences over an arbitrary finite field and provides formulas for the expected linear complexity and its variance of sequences Sn of length n over GF(q). He shows that the variance approaches 1/q when q approaches ∞. He presents criteria that could be useful when using the linear complexity profile for investigating the randomness of sequences over GF(q). Finally, the author investigates how useful these criteria are by comparing the results with other randomness tests
Linear complexity profile of sequences over the field GF(Q)
No full textSummary form only given. The author extends Reuppel's concept of the linear complexity profile of binary sequences to sequences over an arbitrary finite field and provides formulas for the expected linear complexity and its variance of sequences Sn of length n over GF(q). He shows that the variance approaches 1/q when q approaches ∞. He presents criteria that could be useful when using the linear complexity profile for investigating the randomness of sequences over GF(q). Finally, the author investigates how useful these criteria are by comparing the results with other randomness tests
Preclinical evaluation of lime juice as a topical microbicide candidate
No full textBackground: The continued growth of the global HIV epidemic highlights the urgent need to develop novel prevention strategies to reduce HIV transmission. The development of topical microbicides is likely to take a number of years before such a product would be widely available.
This has resulted in a call for the rapid introduction of simpler vaginal intervention strategies in the interim period. One suggested practice would be vaginal douching with natural products including lime or lemon juice. Here we present a comprehensive preclinical evaluation of lime juice (LiJ) as a potential intervention strategy against HIV.
Results: Pre-treatment of HIV with LiJ demonstrated direct virucidal activity, with 10% juice inactivating the virus within 5 minutes. However, this activity was significantly reduced in the presence of seminal plasma, where inactivation required maintaining a 1:1 mixture of neat LiJ and seminal plasma for more than 5 minutes. Additionally, LiJ demonstrated both time and dosedependent
toxicity towards cervicovaginal epithelium, where exposure to 50% juice caused 75–90% toxicity within 5 minutes increasing to 95% by 30 minutes. Cervicovaginal epithelial cell monolayers were more susceptible to the effects of LiJ with 8.8% juice causing 50% toxicity after 5
minutes. Reconstructed stratified cervicovaginal epithelium appeared more resilient to LiJ toxicity with 30 minutes exposure to 50% LiJ having little effect on viability. However viability was reduced by 75% and 90% following 60 and 120 minutes exposure. Furthermore, repeat application (several times daily) of 25% LiJ caused 80–90% reduction in viability.
Conclusion: These data demonstrate that the virucidal activity of LiJ is severely compromised in the presence of seminal plasma. Potentially, to be effective against HIV in vivo, women would need to apply a volume of neat LiJ equal to that of an ejaculate, and maintain this ratio vaginally for 5–30 minutes after ejaculation. Data presented here suggest that this would have significant adverse
effects on the genital mucosa. These data raise serious questions about the plausibility and safety of such a prevention approach
Thesis for the Degree of Doctor of Philosophy Language Engineering in Grammatical Framework (GF)
No full textThe basis for the work presented is Grammatical Framework (GF) — a grammar formalism based on type theory. It is also a powerful language processor that provides a convenient framework for various multilingual applications. The primary concern of this thesis is the usage of GF as a piece of software. The main results are: • Implementing a syntax editor, which provides a graphical user interface (GUI) for the command-line GF core. • Writing the Russian resource grammar that takes care of the most basic morphological and syntactic rules and serves as a standard library for building application grammars (describing sublanguage domains) in Russian. These results contribute to language engineering in GF on two different levels: • Author level (end-user) — constructing documents in natural languages. • Grammarian level — building a grammar description, which is later used on the author level. One can also distinguish between application and resource grammars. An application grammar focuses of a particular sub-language domain, while resource grammar is a general-purpose grammar that forms a basis for application grammars
A systolic exponentiator for finite fields GF(2m)
No full text[[abstract]]© 1992 Institute of Electrical and Electronics Engineers - The author presents a novel parallel-in-parallel-out bit-level systolic array with unidirectional data flow for computing exponentiation in GF(2m). The array is highly regular and modular, and thus well it is suited to VLSI implementation. In addition, it can provide the maximum throughput in the sense of producing new results at a rate of one per clock cycle. Compared to a previously known systolic (GF2m) exponentiator with the same throughput performance, the proposed system requires much less chip area, has smaller latency, and makes it easier to incorporate fault-tolerant design[[department]]電機工程學
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