1,615 research outputs found
Multicriterion Synthesis of Intelligent Control Systems of Generating Unit of Nuclear Power Station
The paper is devoted to solution of some problems in nuclear power station generating unit intellectual control systems using genetic algorithms on the basis of control system model development, optimizations methods of their direct quality indices and improved integral quadratic estimates. Some mathematical vector models were obtained for control system multicriterion quality indices with due consideration of stability and quality indices criteria, this increasing the reliability of optimal control system synthesis. Optimal control systems with fuzzy controllers were synthesized for nuclear reactor, steam generator and steam turbine, thus allowing comparison between fuzzy controllers and traditional PID controllers. Mathematical models built for nuclear power station generating unit control systems, including nuclear reactor, steam generator, steam turbine and their control systems interacting under normal operational modes, which permitted to perform parametrical synthesis of system and to study various power unit control laws. On the basis of power unit control system models controllers were synthesized for normal operational modes
Multicriterion Synthesis of Intelligent Control Systems of Generating Unit of Nuclear Power Station
The paper is devoted to solution of some problems in nuclear power station generating unit intellectual control systems using genetic algorithms on the basis of control system model development, optimizations methods of their direct quality indices and improved integral quadratic estimates. Some mathematical vector models were obtained for control system multicriterion quality indices with due consideration of stability and quality indices criteria, this increasing the reliability of optimal control system synthesis. Optimal control systems with fuzzy controllers were synthesized for nuclear reactor, steam generator and steam turbine, thus allowing comparison between fuzzy controllers and traditional PID controllers. Mathematical models built for nuclear power station generating unit control systems, including nuclear reactor, steam generator, steam turbine and their control systems interacting under normal operational modes, which permitted to perform parametrical synthesis of system and to study various power unit control laws. On the basis of power unit control system models controllers were synthesized for normal operational modes
Reference Database of CrossLaps and Osteocalcin for a Healthy Iranian Population
Markers of bone turnover are becoming an important tool for practitioners in the management
of osteoporosis. Therefore, it is essential to establish a reference database of the markers before
using them in various clinical settings.
A total of 785 individuals (37% males, 63% females) without apparent or suggested
abnormalities affecting bone mass were randomly selected from 13 clusters in Bushehr Port in
southern Iran. The serum CrossLaps ELISA and the N-MID Osteocalcin ELISA were used for the
quantitative measurement of CrossLaps and osteocalcin in sera. Bone mineral density was
determined for the lumbar spines (L2-L4), proximal femur (neck), and forearm (the distal part) using
dual-energy X-ray absorptiometry.
Men had higher biochemical serum bone markers (P<0.0001). In women, there were progressive
increases in serum CrossLaps after 30 years of age, peaking at >60 years. In men, serum
CrossLaps levels were decreased progressively by increases in age, with the peak at 20 – 29 years.
In women, there was a significant decrease in serum osteocalcin from 20 – 29 years to 30–49 years,
followed by a progressive increases during 50 – 59 years, with the peak at >60 years. In men, the
highest concentrations for serum osteocalcin occurred at 20 – 29 years. At all sites checked for
bone mineral densitys, women in the high osteocalcin quartile had the lowest mean bone mineral
densitys values, but women in the high CrossLaps quartile had the lowest mean bone mineral
densitys at lumbar and radial sites. However, in men, bone mineral densitys values at neither site
differed between the lowest and the highest quartiles of serum biochemical bone markers.
We presented a five- year age-specific mean values of bone markers in a general healthy Iranian
population. Only women in the high osteocalcin and CrossLaps quartiles had the lowest mean
bone mineral densitys values at the lumbar and radial sites. Our results suggest that the
significance of osteoclastic bone resorption or bone formation as a determinant of bone mineral
densitys may depend on sex.
Archives of Iranian Medicine, Volum
The association of metabolic syndrome and Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex virus type 1: The Persian Gulf Healthy Heart Study
BACKGROUND: The metabolic syndrome together with insulin resistance and their consequences are basic factors in pathogenesis of atherosclerosis. Chronic infections with herpes simplex virus type 1 (HSV-1), cytomegalovirus (CMV), and Chlamydia pneumoniae are associated with the development of atherosclerosis and coronary heart disease. The infectious aspects of metabolic syndrome have not been investigated. METHODS: In a cross-sectional, population-based study, we used National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP)-III criteria in 1791 subjects, aged 25 years and over, selected by cluster random sampling in three Iranian ports in the northern Persian Gulf. Sera were analyzed for IgG antibodies to Chlamydia pneumoniae, HSV-1, Helicobacter pylori (H. pylori) and CMV using ELISA. RESULTS: In multiple logistic regression analysis, of the infectious agents, CMV [OR = 1.81 (1.05–3.10); p = 0.03], H. pylori [OR = 1.50 (1.12–2.00); p = 0.007] and Chlamydia pneumoniae [OR = 1.69 (1.27–2.25); p < 0.0001] showed a significant association with the metabolic syndrome in men and HSV-1 [OR = 1.95 (1.22–3.11); p = 0.005], H. pylori [OR = 1.45 (1.09–1.94); 0.01] and Chlamydia pneumoniae [OR = 1.65 (1.23–2.21); p = 0.001] in women. CONCLUSION: The metabolic syndrome, which occurs very frequently in the general population, has a significant association with prior infection with Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus and herpes simplex virus type 1. Hypothesis about participation of infection in pathogenesis of metabolic syndrome should be investigated
Serum visfatin and vaspin levels in normoglycemic first-degree relatives of Iranian patients with type 2 diabetes mellitus
Aim: To investigate circulating visfatin and vaspin levels in first-degree relatives of subjects
with type 2 diabetes mellitus (FDRs) who frequently have higher value of HOMA-IR and beta
cell dysfunction.
Methods: Serum visfatin and vaspin concentrations were measured in 179 Iranian subjects
(90 normoglycemic FDRs and 89 age- and sex-matched healthy controls) using enzymelinked
immunosorbent assay (ELISA) methods.
Result: Serum visfatin levels were significantly lower in the FDRs when compared to the
controls (1.71 � 0.93 ng/ml versus 2.69 � 2.02 ng/ml, p = 0.0001). However, no significant
difference was found in serum vaspin concentrations between the FDRs and the controls
(0.452 � 0.254 ng/ml versus 0.409 � 0.275 ng/ml, p > 0.05). In multiple logistic regression
analysis, the FDRs showed a significant association with lower visfatin levels after adjustments
for age, sex, Body Mass Index, systolic and diastolic blood pressures, lipid profile,
blood glucose levels and HOMA-IR [odds ratios (OR) = 1.71, 95% confidence interval
(1.30–2.25); p < 0.0001].
Conclusion: The FDRs showed a significant association with lower visfatin levels. The
observed lower circulating visfatin levels in FDRs may suggest a pathophysiological role
for visfatin in beta cell dysfunction in this group
Iran supports a great share of biodiversity and floristic endemism for Fritillaria spp. (Liliaceae): A review.
Iran supports a great share of exotic and/or endemic plant genera and species. The genus Fritillaria (Liliaceae) is a precious part of this botanical richness with 19 species, of which 10 are endemic to the country. However, signs are mounting that the country is truly at a crossroads when it comes to preservation of this national wealth. In this regard, an effective conservation strategy should thoroughly consider the classification of Fritillaria, as conservation practices are compromised by knowledge gaps in systematics and taxonomy. As published studies on Fritillaria in Iran have been sporadic and limited in scope, the aim of this review is to provide information necessary to help bridge these information gaps. Our objective is to facilitate increased understanding of the geographic, taxonomic, cytogenetic and phylogenetic status of Iranian Fritillaria, which is vital to meeting the goal of sustainable conservation of the genus in Iran and neighboring areas
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