We present a faster implementation of the polynomial time primal simplex algorithm due to Orlin [23]. His algorithm requires O(nm min{log(nC), m log n}) pivots and O(n2 m ??n{log nC, m log n}) time. The bottleneck operations in his algorithm are performing the relabeling operations on nodes, selecting entering arcs for pivots, and performing the pivots. We show how to speed up these operations so as to yield an algorithm whose running time is O(nm. log n) per scaling phase. We show how to extend the dynamic-tree data-structure in order to implement these algorithms. The extension may possibly have other applications as well.

In our ongoing research for secondary metabolites from the Formosan soft corals, six sesquiterpenoids namely GN76-9-1 (1), GN76-10-3 (2), GN76-12-6-10-1 (3), GN76-25-1 (4), GN76-25-5 (5), and GN76-30-5 (6) were isolated from Lemnalia flava (GN76). Among these secondary metabolites, compound 1 possessing a ylangene-type skeleton is a new natural product. Chromatographic separation of the extracts of the Formosan soft coral Efflatounaria tottoni yielded one known compound, GN79-11-3 (7), having an alcyonolide-type structure. In addition, two known germacrane-type sesquiterpenoids, GN82-11-4-2-15 (8) and GN82-16-5-6-25 (9), were isolated from the extracts of the Formosan soft coral Klyxum simplex (GN82). The structures of compounds 1 possessing a ylangene-type skeleton is a new natural product. Chromatographic separation of the extracts of the Formosan soft coral Efflatounaria tottoni yielded one known compound, GN79-11-3 (7), having an alcyonolide-type structure. In addition, two known germacrane-type sesquiterpenoids, GN82-11-4-2-15 (8) and GN82-16-5-6-25 (9), were isolated from the extracts of the Formosan soft coral Klyxum simplex (GN82). The structures of compounds 1-9 were elucidated by extensive spectral analyses. The anti-inflammatory and neuro-protective activities of these compounds were measured in vitro. Compound 2 showed more specific inhibition against the increase of the pro-inflammatory iNOS and COX-2 proteins of LPS-stimulated RAW264.7 macrophage cells. Compound 8 also reveals more specific neuro protective activity to human neuroblastoma cells SH-SY5Y.

HSV-2 may have adverse consequences in HIV. I evaluated the impact of HSV-2 co-infection on (highly active antiretroviral therapy)-untreated HIV infection in a systematic review of observational studies (study 1) and a retrospective cohort (study 2). I further evaluated whether HSV reactivation rates in co-infected persons differ by use of suppressive cART (study 3). Study 1 found modest evidence that HSV-2 seropositivity may be associated with accelerated progression to opportunistic infection or clinical AIDS, but not with increased HIV viral load. Some evidence suggests that HSV-2 disease activity is associated with increased HIV viral load and decreased CD4 counts. Study 2 compared rates of CD4 count change by HSV-2 status (Focus HerpeSelect ELISA) among 218 patients with a past period of ART-untreated follow-up using mixed linear regression models. No significant difference in the rate of CD4 count change was observed in HSV-2 seropositives at +13.6 cells/mm3/year (p=0.12) in univariate analysis, and -4.5 cells/mm3/year (p=0.68) in analysis adjusted for sex, HSV-1, oral and genital HSV symptoms, immigrant status, and immigrant*time interaction. These findings support the need for carefully designed and executed studies of HSV-2 suppression as an adjunctive management strategy for HIV disease, but raise questions regarding the exact mechanism of negative synergy between these viruses and the relative importance of HSV-2 latency and replication in driving these effects. In Study 3, 44 cART-naïve and 41 treated (HIV RNA<50 copies/mL) HIV+ adults with HSV-1 and/or 2 co-infection collected oral, genital and anal swabs daily for 28 days. Negative binomial models were used to quantify the relationship between cART and HSV shedding (Roche LightCycler HSV1/2). Overall HSV shedding was low, at a median (IQR) of 3.6% (0, 14.3%) of days. No relationship was seen between cART and HSV-1 or 2 shedding in univariate (RR=1.55, 95%CI=0.83,2.87) or multivariate analysis adjusted for sex, baseline CD4, recent immigrant status, and time since HIV diagnosis (aRR=1.05, 95%CI=0.43,2.58). Null results were also observed for HSV-1 and HSV-2 considered separately. That HSV shedding persists despite cART suggests that trials of anti-HSV drugs for improving HIV outcomes may be warranted in such patients.

In the study on the chemical constituents from the Formosan marine organisms, four steroids, including three cholanic acid type metabolites, deoxycholic acid 3,12-diacetate (1), deoxycholic acid 3,12-diacetate-24-methyl ester (2), 3£\,7£\,12£\-triacetoxy-5£]-cholanic acid (3), and a principal steroid, gorgosterol (4), were isolated from the soft coral Klyxum simplex, collected at southern Taiwan coast. The structures of steroids 1-4, were elucidated by extensive spectroscopic methods, particularly in 1D and 2D NMR experiments. To best of our knowledge, there is no report on the isolation of cholanic acid type steroids from any marine source. Based on detailed analysis, steroid 2 was found to be a new natural product and this is the first time to isolate steroid 1 from natural resource. Furthermore, two known isoquinoline quinones, mimosamycin (5) and O-demethylrenierone (6) and a known steroid,24,28-didehydroaplysterol (7), were obtained from an Indonesian sponge belonging to the genus Halichondria (Halichondriidae). The structures of metabolites 5-7 were determined by spectral data analysis and by comparison with the spectral and physical data of other known compounds. The antimicrobial activity of compounds 1-7 against Staphylococcus aureus were assayed. It was found that compounds 1, 5 and 6 showed antimicr- obical activity toward Staphylococcus aureus.

Thesis (Ph. D.)--University of Chicago, Committee on Virology, 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Committee on Virology, June 2001. / Includes bibliographical references. Also available on the Internet.

Τα Μαθηματικά, που στο αρχικό στάδιο ανάπτυξής τους αποτελούσαν κυρίως ένα σύνολο εμπειρικών κανόνων για την εκτέλεση πράξεων, σήμερα έχουν γίνει απαραίτητα στη ζωή μας, εισχωρώντας αποφασιστικά με ταχύτατους ρυθμούς σε κάθε σύγχρονο κλάδο επιστημονικής δραστηριότητας. Ο Γραμμικός Προγραμματισμός είναι ένας από τους πιο εφαρμοσμένους κλάδους της επιστήμης των μαθηματικών με πληθώρα εφαρμογών στην επιστήμη των ηλεκτρονικών υπολογιστών και ασχολείται με τη επίλυση του γραμμικού μοντέλου στην Επιχειρησιακή Έρευνα. Για το σκοπό αυτό μελετάει τις ιδιότητες του γραμμικού προβλήματος, κατασκευάζει τρόπους επίλυσης και εξετάζει τρόπους εφαρμογής των αποτελεσμάτων στη λήψη πολύπλοκων αποφάσεων. Από την οικονομική σκοπιά, ο Γραμμικός Προγραμματισμός είναι μια τεχνική που ασχολείται με το πρόβλημα της βέλτιστης κατανομής των περιορισμένων πόρων ενός συστήματος σε ανταγωνιζόμενες δραστηριότητες κατά τον καλύτερο δυνατό τρόπο. Ακόμη χρησιμοποιείται για τη επίλυση προβλημάτων ενέργειας, διοίκησης προσωπικού, προστασία του περιβάλλοντος, καθώς επίσης και προβλημάτων που αφορούν την ανάθεση πεπερασμένων πόρων σε ανταγωνιστικές απαιτήσεις (π.χ. κατανομή εργατικού δυναμικού, πρώτων υλών και τεχνολογικού εξοπλισμού). Η αρχική μαθηματική διατύπωση του προβλήματος καθώς και μια συστηματική διαδικασία λύσης του, η μέθοδος Simplex, οφείλεται στον G. B. Dantzig στα 1947. Νωρίτερα διάφορα προβλήματα τύπου γραμμικού προγραμματισμού είχαν διαμορφωθεί και επιλυθεί. Τα σημαντικότερα από αυτά αφορούν το πρόβλημα μεταφοράς (Hitchcock 1941, Koopmans 1949) και το πρόβλημα της δίαιτας (Stigler 1945). Ο Dantzig ήταν όμως ο άνθρωπος που κατασκεύασε το γενικό πλαίσιο και ταυτόχρονα υπέδειξε τη μέθοδο επίλυσης του. Θεωρείται σαν μια από τις πιο σπουδαίες μαθηματικές ανακαλύψεις των μέσων χρόνων του εικοστού αιώνα και στις μέρες μας αποτελεί ένα μοντέλο ευρείας χρήσης για καθημερινά ζητήματα των περισσότερων μεσαίου και μεγάλου μεγέθους εμπορικών - βιομηχανικών εταιρειών. Στο πρώτο κεφάλαιο της παρούσης εργασίας επιδεικνύεται η ανάγκη δημιουργίας ενός μαθηματικού μοντέλου για την περιγραφή και επίλυση του γραμμικού προβλήματος μας. Ενώ στο δεύτερο κεφάλαιο διατυπώνεται και περιγράφεται ο Αλγόριθμος Simplex στη επίλυση ενός Γραμμικού Προβλήματος Προγραμματισμού. Μια από τις σημαντικότερες πτυχές του Γραμμικού Προγραμματισμού αναπτύσσεται στο 8 τρίτο κεφάλαιο, η έννοια του Δυικού προβλήματος, το οποίο σχετίζεται με τη δομή του αρχικού προβλήματος και τυχαίνει να είναι και αυτό ταυτόχρονα επίλυση. Το κεφάλαιο 4 επικεντρώνεται στις εναλλακτικές μεθόδους επίλυσης του προβλήματος και εισάγει τη βασική έννοια της υπολογιστικής Πολυπλοκότητας. Συγκεκριμένα αναπτύσσεται ο Αλγόριθμος Karmakar και ο πρωτεύον – δυικος αλγόριθμος εσωτερικού σημείου. / Mathematics, which were mostly thought to be a set of empirical rules for the execution of operations and instruments, especially during their initial stage of development, have now become indispensable in our lives, decisively penetrating in each and every contemporary field of scientific activity. Linear programming is one of the most applied fields of this fast-growing science and is characterised by a plethora of applications in the field of computer science and deals with the solution of the linear model in Operational Research. To this end, it studies the properties of the linear problem, develops methods for solving the problem and investigates ways of applying the results in making complex decisions. From a business/economic perspective, Linear Programming is a technique that deals with the problem of optimal distribution of a system’s limited resources to competing activities in the best possible way. In addition to the above, it is used when required to solve varying problems such as energy, human resource management, and protection of the environment as well as problems that have to do with delegating finite resources to competing requirements (i.e. distribution of manpower, raw materials and technological equipment). The initial mathematical formulation of the problem as well as a systematic solution process, known as the Simplex method, is due to G. B. Dantzig, in 1947. Earlier than that various problems of linear programming were developed and solved. The most important of these are concerned with the transfer problem (Hitchcock 1941, Koopmans 1949) and the diet problem (Stigler 1945). Dantzig however, was the first one to construct the general framework and demonstrated the appropriate solving method at the same time. It is considered to be one of the most important mathematical discoveries of the middle ages of the twentieth century. Nowadays it is a model broadly-used for everyday matters of most medium and large commercial - industrial companies. The first chapter of the current project will demonstrate the need for creating a mathematical model for the description and solution of our linear problem. While the second chapter sets out and describes the Simplex Algorithm in solving a Linear Programming Problem. One of the most important aspects of Linear Programming is developed in the third chapter, the concept of the Dual Problem, which relates to the structure of the initial problem and happens to be a solution to the problem at the same time. Finally, chapter 4 concentrates on the alternative methods of solving the problem 10 and introduces the basic concept of Computing Complexity. More specifically, Karmakar algorithm is developed as well as the primal-dual internal-point algorithm.

HSV-2 may have adverse consequences in HIV. I evaluated the impact of HSV-2 co-infection on (highly active antiretroviral therapy)-untreated HIV infection in a systematic review of observational studies (study 1) and a retrospective cohort (study 2). I further evaluated whether HSV reactivation rates in co-infected persons differ by use of suppressive cART (study 3). Study 1 found modest evidence that HSV-2 seropositivity may be associated with accelerated progression to opportunistic infection or clinical AIDS, but not with increased HIV viral load. Some evidence suggests that HSV-2 disease activity is associated with increased HIV viral load and decreased CD4 counts. Study 2 compared rates of CD4 count change by HSV-2 status (Focus HerpeSelect ELISA) among 218 patients with a past period of ART-untreated follow-up using mixed linear regression models. No significant difference in the rate of CD4 count change was observed in HSV-2 seropositives at +13.6 cells/mm3/year (p=0.12) in univariate analysis, and -4.5 cells/mm3/year (p=0.68) in analysis adjusted for sex, HSV-1, oral and genital HSV symptoms, immigrant status, and immigrant*time interaction. These findings support the need for carefully designed and executed studies of HSV-2 suppression as an adjunctive management strategy for HIV disease, but raise questions regarding the exact mechanism of negative synergy between these viruses and the relative importance of HSV-2 latency and replication in driving these effects. In Study 3, 44 cART-naïve and 41 treated (HIV RNA<50 copies/mL) HIV+ adults with HSV-1 and/or 2 co-infection collected oral, genital and anal swabs daily for 28 days. Negative binomial models were used to quantify the relationship between cART and HSV shedding (Roche LightCycler HSV1/2). Overall HSV shedding was low, at a median (IQR) of 3.6% (0, 14.3%) of days. No relationship was seen between cART and HSV-1 or 2 shedding in univariate (RR=1.55, 95%CI=0.83,2.87) or multivariate analysis adjusted for sex, baseline CD4, recent immigrant status, and time since HIV diagnosis (aRR=1.05, 95%CI=0.43,2.58). Null results were also observed for HSV-1 and HSV-2 considered separately. That HSV shedding persists despite cART suggests that trials of anti-HSV drugs for improving HIV outcomes may be warranted in such patients.

To investigate the localization and targeting of sodium channels in neurons, an efficient means of gene delivery will need to be established. Two amplicon-based viral approaches and a recombinant whole virus approach were attempted in order to package and express RIIA sodium channel tagged with a c-myc epitope (RIIA-myc) with the ultimate purpose of developing a Herpes virus-based model system for targeting studies. / Immunofluorescent staining of transfected epithelial cells was carried out to demonstrate that constructs created for use in these HSV-based approaches were capable of a high level of expression of RIIA-myc. Measurements of $ beta$-galactosidase reporter gene expression observed in cultured cells infected with RIIA amplicon virus suggested successful packaging of amplicon DNA. However, RIIA-myc expression from amplicon virus was not apparent, which may suggest recombination events occurred upon packaging of constructs. Difficulties in selection for recombinants with acyclovir prevented the recombinant whole virus approach from being pursued.

Bibliography: leaves 82-114. / viii, 114, [32] leaves, [14] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Depts. of Microbiology and Immunology, 1993