64 research outputs found
The role of PTEN in cardioprotection against ischaemia-reperfusion injury
No full textActivation of the PI3K/AKT pathway protects the heart from ischaemia-reperfusion injury.
Phosphatase and Tensin Homolog deleted on Chromosome10 (PTEN) is a negative regulator
of this pathway. The hypothesis on which this thesis was based stated that inhibition of PTEN
would confer protection against ischaemia-reperfusion injury. PTEN was reduced using: 1) a
PTEN inhibitor, bpV(HOpic), 2) a mouse model of PTEN haploinsufficiency and 3) PTEN
siRNA. The effects of PTEN reduction on ischaemia-reperfusion injury were investigated by
using: 1) an isolated perfused heart model of ischaemia-reperfusion injury, 2) an isolated
cardiomyocyte model of ROS induced mitochondria damage and 3) a cellular model of
hypoxia-reoxygenation injury. No protection against ischaemia-reperfusion was observed in
isolated perfused myocardium from C57BL/J6 mice, which were perfused with bpV(HOpic), or
from PTEN+/-mice. Likewise, no protection against ROS induced mitochondrial damage was
observed in isolated cardiomyocytes from the PTEN+/- mice. In these models an increase in
AKT activity was recorded, however, this was not sufficient to confer cardioprotection.
Similarly, H9c2 rat myoblast cells, silenced for PTEN expression using siRNA, were not
protected against hypoxia-reoxygenation injury. Nevertheless, in isolated C57BL/J6 hearts
perfused with bpV(HOpic) and in myocardium from PTEN+/- mice, when the PI3K/AKT
pathway was stimulated by the cardioprotective intervention of ischaemic preconditioning a
reduced threshold for protection was achieved. To conclude, the level of PTEN inhibition
achieved in this study was not sufficient to bestow protection against simulated ischaemiareperfusion
injury. However, it appears that reductions in PTEN can increase the sensitivity
towards cardioprotection
Figs. 7–14. Mesobdella gemmata. 7, 8, 9 in Leech Collections from Chile Including Two New Species of Helobdella (Annelida: Hirudinida)
No full textFigs. 7–14. Mesobdella gemmata. 7, 8, 9. Live specimens from ChanChan Alto feeding on the second author. 10. Dorsal view of cephalic somites. 11. Lateral view of caudal somites in which no respiratory auricle is visible. 12. Dissection of clitellar somites revealing the median reproductive apparatus including the penis sheath (pe), epididymes (e), vaginal sac (v), and an ovary (o). 13. Female median reproductive apparatus exhibiting independent oviducts (arrowheads) and a small vaginal caecum (vc). 14. Male median reproductive apparatus showing the stout penis and sheath (pe) and associated epididymes (e).Published as part of SIDDALL, MARK E. & BORDA, ELIZABETH, 2004, Leech Collections from Chile Including Two New Species of Helobdella (Annelida: Hirudinida), pp. 1-20 in American Museum Novitates 3457 (1) on page 5, DOI: 10.1206/0003-0082(2004)4572.0.CO;2, http://zenodo.org/record/538269
The taxonomist - an endangered race : a practical proposal for its survival
No full textBackground: Taxonomy or biological systematics is the basic scientific discipline of biology, postulating hypotheses of identity and relationships, on which all other natural sciences dealing with organisms relies. However, the scientific contributions of taxonomists have been largely neglected when using species names in scientific publications by not citing the authority on which they are based.
Discussion: Consequences of this neglect is reduced recognition of the importance of taxonomy, which in turn results in diminished funding, lower interest from journals in publishing taxonomic research, and a reduced number of young scientists entering the field. This has lead to the so-called taxonomic impediment at a time when biodiversity studies are of critical importance.
Here we emphasize a practical and obvious solution to this dilemma. We propose that whenever a species name is used, the author(s) of the species hypothesis be included and the original literature source cited, including taxonomic revisions and identification literature - nothing more than what is done for every other hypothesis or assumption included in a scientific publication. In addition, we postulate that journals primarily publishing taxonomic studies should be indexed in ISISM.
Summary: The proposal outlined above would make visible the true contribution of taxonomists within the scientific community, and would provide a more accurate assessment for funding agencies impact and importance of taxonomy, and help in the recruitment of young scientists into the field, thus helping to alleviate the taxonomic impediment. In addition, it would also make much of the biological literature more robust by reducing or alleviating taxonomic uncertainty.
Keywords: Taxonomy crisis; taxonomic impediment; impact factor; original species description; citation index; systematic
A Study of Optimization Techniques and Their Applications to Design
No full textTitle: A Study of Optimization Techniques and Their Applications to Design, Author: Mir W. Wahed, Location: ThodeThis thesis consists of a general survey of existing mathematical
optimization techniques and of an attempt to apply such techniques to
various design situations. Several analytical and numerical techniques
of determining extrema of univariable and multivariable known or unknown
functions subjected to equality and inequality constraints are investigated
when such extrema lie either in the interior or on the boundary
of a given region. Design examples are worked out to illustrate the
applicability and the limitations of the methods and the procedure of
attacking a problem for solution. Some of these applications are
original with the author. An extensive survey of applications of
optimization techniques to several design situations is also included.
No such design orientated survey seems to have ever been taken. Comments,
regarding the applicability of these techniques to various design situations
and suggestions for further research are made.ThesisMaster of Engineering (ME
A Study and Design of an Automated Information Storage and Retrieval System
No full textThe purpose of this project has been twofold. First, a thorough literature survey has been conducted in the field of information storage and retrieval with primary attention given to computer oriented techniques. The systems used and the theory behind them have been of more concern to the author than the actual equipment used because it is felt that equipment will change very rapidly as it has in the past whereas the basic system, in most cases, will prevail. The second part of this project has been the design of an overall automated trial information system with the needs of the designer being of prime importance.ThesisMaster of Engineering (ME
Design Optimization of a Shaft on Two Bearings
No full textTitle: Design Optimization of a Shaft on Two Bearings, Author: Laurentiu Popa, Location: ThodeThe purpose of this project was to develop an aid to designing machinery shafts to find the optimum design for most shaft design applications met in design engineers' practices, to reduce the cost of the shafts. The result was a computer package capable of handling the design optimization of step shafts supported on two bearings which will find the shaft design with minimum cost. Additional benefits were obtained such as reducing engineering time and cost, increasing
reliability of the design, etc.ThesisMaster of Engineering (ME
Design Optimization of Vertical Water wheel Generator Lower Brackets
No full textTitle: Design Optimization of Vertical Water wheel Generator Lower Brackets, Author: David L. Saxton, Location: ThodeIn this thesis the functions, method of structural analysis,
and design limits of lower brackets are described. The results
of an investigation of the design formulae, the development of
a method of optimizing the design, and the results of an experimental
check on the accuracy of the design formulae are presented. The maximum stresses as determined by experiment were in good
agreement with the theoretical predictions, however, the stresses
measured at other locations and the deflection were not. The
optimizing technique used was successful in reducing the value
of the optimization function from an initial starting point and
produced consistent results with different starting points.ThesisMaster of Engineering (ME
Pseudo-Boolean Programming for Bivalent Optimization
No full textTitle: Pseudo-Boolean Programming for Bivalent Optimization, Author: M. Natesan, Location: ThodeThis thesis introduces an effective computational algorithm making
use of Boolean algebra for solving bivalent optimization problems with
linear and nonlinear constraints. This method is a combination of the
algorithm suggested by Hammer and the branch and bound method. The whole
system of constraints is replaced by a single Boolean resolvent function
and the solutions of this resolvent are found by branch and bound method
which are found to be the feasible solutions of the system of constraints.
Some practical applications are also discussed.ThesisMaster of Engineering (ME
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