Lakes College

Induction motors are the most widely adopted alternating current machines in industry. Requirements for precise and efficient control of such motors has led to developments in high performance drives, namely direct torque control. The induction motors parameters must be ascertained to accurately tune the drive to its optimum performance, failing to do so would result in an inadequate response from the drive, leading to sluggish dynamics and premature deterioration of the motor and drive. The process of optimizing the drive parameters is laborious, costly and time consuming. MathWorks provides software to model and modify the parameters of a direct torque control drive, however the trial and error retuning methods are tedious. This paper presents the development of an AC induction motor and direct torque control drive parameter retuning app which can accurately predict the motor and drive parameters and then simulate its performance using solely the motor nominal power rating. The app utilises the AC4 block and pre-set induction motor models from within the Math Works Specialised Power Systems library. The effectiveness of the app was first tested with known data points and then at random query points and operating conditions, all of which produced satisfactory results in significantly reduced time.

Although technical problems of thyroid testing have largely been resolved by modern assay technology, biological variation remains a challenge. This applies to subclinical thyroid disease, non-thyroidal illness syndrome, and those 10% of hypothyroid patients, who report impaired quality of life, despite normal thyrotropin (TSH) concentrations under levothyroxine (L-T4) replacement. Among multiple explanations for this condition, inadequate treatment dosage and monotherapy with L-T4 in subjects with impaired deiodination have received major attention. Translation to clinical practice is difficult, however, since univariate reference ranges for TSH and thyroid hormones fail to deliver robust decision algorithms for therapeutic interventions in patients with more subtle thyroid dysfunctions. Advances in mathematical and simulative modeling of pituitary–thyroid feedback control have improved our understanding of physiological mechanisms governing the homeostatic behavior. From multiple cybernetic models developed since 1956, four examples have also been translated to applications in medical decision-making and clinical trials. Structure parameters representing fundamental properties of the processing structure include the calculated secretory capacity of the thyroid gland (SPINA-GT), sum activity of peripheral deiodinases (SPINA-GD) and Jostel’s TSH index for assessment of thyrotropic pituitary function, supplemented by a recently published algorithm for reconstructing the personal set point of thyroid homeostasis. In addition, a family of integrated models (University of California-Los Angeles platform) provides advanced methods for bioequivalence studies. This perspective article delivers an overview of current clinical research on the basis of mathematical thyroid models. In addition to a summary of large clinical trials, it provides previously unpublished results of validation studies based on simulation and clinical samples.

In light of several recent recommendations to use total thyroxine (T4) measurements in the diagnosis of thyroid function in pregnancy (in particular, "Clinical Practice Guidelines for Hypothyroidism in Adults," cosponsored by the American Thyroid Association and the American Association of Clinical Endocrinologists, which promote the use of T4 over free T4 [FT4 ]), we have examined the implications of employing T4 for diagnostic discrimination in both pregnant and nonpregnant patient panels. Use of T4 assays has significant drawbacks in this regard, and we believe that the suggestion is a retrograde step in thyroid function testing. Analysis of the interplay between the concentrations of T4 and thyroxine-binding globulin (TBG), typifying their respective reference ranges in either the nonpregnant or pregnant euthyroid state, shows that the effective T4 range is widened significantly by the accompanying hidden variation in TBG levels. Accordingly FT4 assays that fully compensate for serum T4-binding protein concentrations should discriminate dysfunctionality from normality more efficiently than total hormone measurements, whether in pregnant or nonpregnant states. The euthyroid FT4 reference ranges typical of late pregnancy should also be more compact than those for the total hormone, because of the increased dominance of higher, though equivalently variable TBG concentrations on T4 levels. Parallel effects on T4 from similarly variable, though lower concentrations of TBG are indicated in the nonpregnant group. While acknowledging the difficulties in FT4 measurement arising from inconsistent calibration of present-day commercial assays, this finding questions the recommendation that total hormone assays should supersede the former in pregnancy.

BackgroundDespite the possibility of preventing many cases of HIV, malaria and unplanned pregnancy, protective measures are often not taken by those at risk in Uganda. The study aim was to explore young people’s perspectives on the reasons why this is so.MethodsFocus groups were conducted with 100 secondary school and college students in Kanungu, Uganda in 2011. Three parallel groups considered HIV, malaria and family planning, and common messages were then explored jointly in a workshop based on the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation and Maintenance).ResultsParticipants identified various reasons why preventive action was not always taken. They worried about the effectiveness and side effects of several key interventions: condoms, antiretroviral treatment, various contraceptives and impregnated mosquito nets. Cost, rural isolation and the quality and availability of health services also limited the extent to which people were able to follow health advice. Although there was respect for policy supporting abstinence and fidelity, it was seen as hard to follow and offering inadequate protection when gender imbalance put pressure on women to have sex.ConclusionsThere is an opportunity to improve the uptake of preventive measures by tackling the misconceptions and fears that participants reported with clear, evidence-based messages. This should be done in a way that encourages more open communication about reproductive health between men and women, that reaches out to isolated communities, that draws on both voluntary and government services and enlists young people so that they can shape their future.

We have read with interest recent reports of the measurement of free thyroxine and free triiodothyronine by ultrafiltration and tandem mass spectrometry (1)(2)(3)(4). There is, however, a fundamental flaw in these studies that we wish to bring to general attention. Ultrafiltration of serum was routinely carried out close to room temperature (25 °C)(1 …