Model reaching adaptive-robust control law for vibration isolation systems with parametric uncertainty

Adaptive control has been used for active vibration isolation and vehicle suspensions systems. A model reference adaptive control law is used for the plant to track the ideal reference model. In a model reaching adaptive control approach, the ideal of a skyhook target without using a reference model is achieved. In this paper, a novel approach, a model reaching adaptive-robust control law is studied for active vibration isolation systems. A dynamic manifold for ideal system is defined using the ideal of a skyhook target model system parameters. First, a new Lyapunov function is defined. Based on the Lyapunov stability theory, a model reaching adaptive and a robust control laws are derived for the uncertain system to reach the ideal manifold. Parameters and upper bounding functions are estimated as a trigonometric function depending on the relative displacements, velocities and the defined manifold. The developed adaptive and the robust compensators are combined and this combination is proposed as an adaptive-robust control law. After that, the controller is applied to a vehicle suspension system and the ideal of a skyhook target without using a reference model is achieved. The results also show that the proposed robust control law can increase the comfort of the vehicle active suspension systems and the ride comfort is remarkably increased

Comparison of apparent diffusion coefficient values among different MRI platforms: a multicenter phantom study

PURPOSE:We aimed to compare apparent diffusion coefficient (ADC) values among magnetic resonance imaging (MRI) scanners from different vendors.MATERIALS AND METHODS:We used a custom-made phantom solution consisting of distilled water, 0.9% NaCl, 25% NaCl, and shampoo for diffusion-weighted MRI (DW-MRI) examinations. DW-MRI was performed with similar sequence parameters using six different 1.5 Tesla MR scanners (scanners A–F). ADC maps were automatically constructed for all DW-MR images (b factors of 0 and 1000 s/mm2). ADC measurements were performed using regions of interest and seven different software programs, including four different postprocessing workstations, two different picture archiving and communication systems, and operator console software for each MR scanner.RESULTS:The ADC values generated by scanners A and F were higher and those of scanner B were lower than those generated by the other scanners (P = 0.002). The intravendor difference in the ADC values averaged from scanners D, E, and F was statistically significant (P < 0.001). The difference between the ADC values obtained by scanners C and E was not statistically different (P = 0.15).CONCLUSION:ADC values may differ among different MRI systems used for DW-MRI. Thus, the MRI vendor should be considered when using DW-MRI in a clinical setting

Perspectives of the Apiaceae Hepatoprotective Effects - A Review

The liver has the crucial role in the regulation of various physiological processes and in the excretion of endogenous waste metabolites and xenobiotics. Liver structure impairment can be caused by various factors including microorganisms, autoimmune diseases, chemicals, alcohol and drugs. The plant kingdom is full of liver protective chemicals such as phenols, coumarins, lignans, essential oils, monoterpenes, carotenoids, glycosides, flavonoids, organic acids, lipids, alkaloids and xanthenes. Apiaceae plants are usually used as a vegetable or as a spice, but their other functional properties are also very important. This review highlights the significance of caraway, dill, cumin, aniseed, fennel, coriander, celery, lovage, angelica, parsley and carrot, which are popular vegetables and spices, but possess hepatoprotective potential. These plants can be used for medicinal applications to patients who suffer from liver damage

Effect of radiation dose reduction on image quality in adult head CT with noise-suppressing reconstruction system with a 256 slice MDCT

WOS: 000354950100028PubMed ID: 26103494The purpose of our study was to investigate the effect of iterative reconstruction (IR) as a dose reduction system on the image quality (IQ) of the adult head computed tomography (CT) at various low-dose levels, and to identify ways of setting the amount of dose reduction. We performed two noncontrast low-dose (LD) adult head CT protocols modified by lowering the tube current with IR which were decided in the light of a group of phantom studies. Two groups of patients, each 100 underwent noncontrast head CT with LD-I and LD-II, respectively. These groups were compared with 100 consecutive standard dose (STD) adult head CT protocol in terms of quantitative and qualitative IQ. The signal-to-noise ratio (SNR) of the white matter (WM) and gray matter (GM) and contrast-to-noise ratio (CNR) values in the LD groups were higher than the STD group. The differences were statistically significant. When the STD and the LD groups were compared qualitatively, no significant differences were found in overall quality. By selecting the appropriate level of IR 34%, radiation dose reduction in adult head CT can be achieved without compromising IQ

Hepatoprotective effects of coriandrum sativum essential oil against acute hepatotoxicity induced by carbon tetrachloride on rats

The aim of this study was to evaluate effect of Coriandrum sativum (CS) essential oil in rat model of carbon tetrachloride (CCl4) induced liver toxicity. Experimental groups were formed as follows: isotonic saline solution (ISS), silibinin, CS-1 (0,3ml/ kg), CS-2 (0,6 ml/kg). Agents were administered intraperitoneally. Blood and liver tissues were collected at the end of the study ended. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured. Liver tissues were evaluated histopathologically. One-way analysis of variance (ANOVA) was used for statistical analyses.As a result silibinin and CS-2 decreased blood AST and ALT levels of their groups and these biochemical results were supported by histopathological results. In conclusion this study has provided evidence that Coriandrum sativum essential oil has significant hepatoprotective effect on carbon tetrachloride induced liver toxicity in rats

Aspects of biology of the deep-water pandalid shrimp Plesionika martia (A. Milne-Edwards, 1883) from Sığacık Bay (eastern Mediterranean)

Some aspects concerning the reproduction, growth, and population dynamics of Plesionika martia were studied. Individuals were collected monthly between May 2008 and April 2009 during surveys conducted using a commercial trawl vessel. Samples were collected from Sığacık Bay (Aegean Sea, eastern Mediterranean) at depths ranging from 494 to 550 m. A total of 2110 individuals (766 males and 1344 females) were caught during these monthly surveys. The carapace length (CL) of the males ranged from 12.4 to 22.1 mm, and in females the CL ranged between 11.5 and 24.9 mm. The values of both CL and weight in females consistently exceeded that of males throughout the year. Although ovigerous females were observed throughout the year, the main reproductive period is suggested to be from May to December. In all groups examined, the values of allometric coeffi cient b were less than 3. Estimates of the Von Bertalanffy growth parameters were L;yen; = 26.25 mm and k = 0.38 year;amp;#8211;1 in females, and L;yen; = 23.63 mm and k = 0.49 year;amp;#8211;1 in males.Bu çalışmada, Ege Denizi (Doğu Akdeniz)’de, P. martia’nın üreme, büyüme ve populasyon dinamikleri çalışıldı. Bireyler aylık olarak, Mayıs 2008 ve Nisan 2009 tarihleri arasında Sığacık Körfezi’nden 494-550 m derinlikler arasından toplandı. Araştırma sürecinde, toplam 2110 P. martia birey (766 erkek ve 1344 dişi) toplandı. Karapas boyu (CL), erkek bireyler için 12,4 mm ve 22,1 mm arasında, dişi bireyler için 11,5 mm ve 24,9 mm arasında ölçüldü. Yıl boyunca, dişilerin ortalama boy (CL) ve ağırlığı (W) erkeklerin ortalama boy ve ağırlığından sürekli olarak yüksek çıktı. Yumurtalı dişiler yıl boyunca gözlendi. Ana üreme periyodu mayıs ve aralık ayları arası olarak tespit edildi. İncelenen tüm gruplarda, allometrik katsayısı (b) 3’ten az bulundu. Von Bertalanffy büyüme parametreleri dişilerde L¥ = 26,25 mm, k = 0,38 year–1, erkeklerde L¥ = 23,63 mm, k = 0,49 year–1 olarak hesaplandı