Intelligent optimal control with dynamic neural networks.

The application of neural networks technology to dynamic system control has been constrained by the non-dynamic nature of popular network architectures. Many of difficulties are-large network sizes (i.e. curse of dimensionality), long training times, etc. These problems can be overcome with dynamic neural networks (DNN).In this study, intelligent optimal control problem is considered as a nonlinear optimization with dynamic equality constraints, and DNN as a control trajectory priming system. The resulting algorithm operates as an auto-trainer for DNN (a self-learning structure) and generates optimal feed-forward control trajectories in a significantly smaller number of iterations. In this way, optimal control trajectories are encapsulated and generalized by DNN. The time varying optimal feedback gains are also generated along the trajectory as byproducts. Speeding up trajectory calculations opens up avenues for real-time intelligent optimal control with virtual global feedback.We used direct-descent-curvature algorithm with some modifications (we called modified-descend-controller-MDC algorithm) for the optimal control computations. The algorithm has generated numerically very robust solutions with respect to conjugate points. The adjoint theory has been used in the training of DNN which is considered as a quasi-linear dynamic system. The updating of weights (identification of parameters) are based on Broyden-Fletcher-Goldfarb-Shanno BFGS method. Simulation results are given for an intelligent optimal control system controlling a difficult nonlinear second-order system using fully connected three-neuron DNN.     

Sezary syndrome--without erythroderma

Sezary syndrome (SS), is described as the classical triad of pruritic erythroderma, lymphadenopathy, and presence of more than 10% of circulating Sezary cells in the peripheral blood. We report on unusual case of advanced cutaneous T - cell lymphoma with classical haematological and histopathological features of Sezary syndrome, but lacking the clinical features of erythroderma. A 66 year old man presented with asymptomatic multiple papules, plaques and nodules and with generalized lymphadenopathy. Peripheral smear showed more than 60% of Sezary cells. Skin and lymph node biopsy showed typical features of T-cell lymphoma and immunohistochemistry and CD marker studies showed the cells to be atypical T-lymphocytes. This unusual case is highlighted to denote that erythroderma need not be taken as a hard and fast criterion for diagnosing Sezary syndrome.     

Liposomal drug delivery systems: an update review

The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon hydration; liposome drug delivery systems have played a significant role in formulation of potent drug to improve therapeutics. Recently the liposome formulations are targeted to reduce toxicity and increase accumulation at the target site. There are several new methods of liposome preparation based on lipid drug interaction and liposome disposition mechanism including the inhibition of rapid clearance of liposome by controlling particle size, charge and surface hydration. Most clinical applications of liposomal drug delivery are targeting to tissue with or without expression of target recognition molecules on lipid membrane. The liposomes are characterized with respect to physical, chemical and biological parameters. The sizing of liposome is also critical parameter which helps characterize the liposome which is usually performed by sequential extrusion at relatively low pressure through polycarbonate membrane (PCM). This mode of drug delivery lends more safety and efficacy to administration of several classes of drugs like antiviral, antifungal, antimicrobial, vaccines, anti-tubercular drugs and gene therapeutics. Present applications of the liposomes are in the immunology, dermatology, vaccine adjuvant, eye disorders, brain targeting, infective disease and in tumour therapy. The new developments in this field are the specific binding properties of a drug-carrying liposome to a target cell such as a tumor cell and specific molecules in the body (antibodies, proteins, peptides etc.); stealth liposomes which are especially being used as carriers for hydrophilic (water soluble) anticancer drugs like doxorubicin, mitoxantrone; and bisphosphonate-liposome mediated depletion of macrophages. This review would be a help to the researchers working in the area of liposomal drug delivery.     

Type 1 choledochal cysts: preoperative evaluation by ultrasound

Type I choledochal cysts were diagnosed on ultrasonography in 14 patients. The cysts were seen as oval or fusiform anechoic structures located in the subhepatic space and separate from the gallbladder. The continuity of the cyst with the bile duct in the porta hepatis was a specific feature for correct diagnosis of the condition.     

The value of endothelium dependent vasodilatation in diagnosing coronary artery disease and its comparison with the results of routine diagnostic tests

OBJECTIVE: To determine the predictive value of flow-mediated vasodilation (FMD) compared with angina pectoris, exercise electrocardiography, and myocardial perfusion imaging (MPI). METHODS: This study was carried out in Shahid Madani Heart Center, Tabriz, Iran from April 2004 to September 2006. A total of 92 patients with chest pain syndrome were enrolled in this study. Using high resolution ultrasound system endothelial function was evaluated, and the result of the flow-mediated dilation (FMD%) was defined as the percent change in the internal diameter of the brachial artery during reactive hyperemia related to baseline. RESULTS: Coronary artery disease (CAD) was documented in 77 (83.7%) patients. The percentage of FMD was lower in patients with CAD compared with those +/- 4.61, p=0.001). In comparison with typical anginal chest pain (sensitivity 46.7%, specificity 80%), exercise stress test (sensitivity 75%, specificity 60%), and MPI (sensitivity 96.5, specificity 55.6%) the receiver operator characteristic curve showed the percentage FMD optimal cut-off value as 相似文献   

Hepatitis B virus genotypes in southwest Iran： Molecular, serological and clinical outcomes

AIM： To investigate the associations of hepatitis B virus （HBV） genotype with HBeAg and anti-HBe status, alanine aminotransferase （ALT） levels and HBV-DNA detection in different groups of HBV-infected patients in southwest Iran. METHODS： A total of 89 HBsAg-positive serum samples were collected from the same number of patients. All sera were then investigated to determine HBV DNA and serological markers. For all the polymerase chain reaction （PCR）-positive samples, biochemical, histopathological assays and genotyping were also performed. RESULTS： Genotype D was the only type of HBV foundin different clinical forms of acute and chronic infections. There was a high prevalence of HBeAg-negative HBV- infected patients with chronic hepatitis （52.7%）. Out of 55 patients with chronic hepatitis, seven （12.7%） were diagnosed with cirrhosis. A significant association between the presence of anti-HBe antibody and an increase in ALT level, among either HBeAg-negative （P = 0.01） or HBeAg-positive （P = 0.026） patients, was demonstrated. No significant differences were observed between the clinical outcomes of HBeAg-positive and -negative individuals （P = 0.24）. CONCLUSION： Genotype D has been recognized as the only type of HBV found in different clinical forms of HBV infections, including cirrhosis, among the residents of southwest Iran. Anti-HBe possibly plays a role in disease progression in some patients with chronic hepatitis, at least for a period of disease.     

Localization and action of Dragon (repulsive guidance molecule b), a novel bone morphogenetic protein coreceptor, throughout the reproductive axis

Bone morphogenetic proteins (BMPs) play important roles in reproduction including primordial germ cell formation, follicular development, spermatogenesis, and FSH secretion. Dragon, a recently identified glycosylphosphatidylinositol-anchored member of the repulsive guidance molecule family, is also a BMP coreceptor. In the present study, we determined the tissue and cellular localization of Dragon in reproductive organs using immunohistochemistry and in situ hybridization. Among reproductive organs, Dragon was expressed in testis, epididymis, ovary, uterus, and pituitary. In the testis of early postnatal mice, Dragon was found in gonocytes and spermatogonia, whereas in immature testes, Dragon was only weakly expressed in spermatogonia. Interestingly, pregnant mare serum gonadotropin treatment of immature mice robustly induced Dragon production in spermatocytes. In adult testis, Dragon was found in spermatocytes and round spermatids. In the ovary, Dragon was detected exclusively within oocytes and primarily those within secondary follicles. In the pituitary, Dragon-expressing cells overlapped FSH-expressing cells. Dragon was also expressed in a number of cell lines originating from reproductive tissues including Ishikawa, Hela, LbetaT2, MCF-7, and JEG3 cells. Immunocytochemistry and gradient sucrose ultracentrifugation studies showed Dragon was localized in lipid rafts within the plasma membrane. In reproductive cell lines, Dragon expression enhanced signaling of exogenous BMP2 or BMP4. The present studies demonstrate that Dragon expression is dynamically regulated throughout the reproductive tract and that Dragon protein modulates BMP signaling in cells from reproductive tissues. The overlap between Dragon expression and the functional BMP signaling system suggests that Dragon may play a role in mammalian reproduction.     

Right ventricular function before and after an uncomplicated coronary artery bypass graft as assessed by pulsed wave Doppler tissue imaging of the tricuspid annulus

Background

Right ventricular (RV) function using myocardial velocities before and after a coronary artery bypass graft (CABG) is not known.

Methods

Using pulsed wave Doppler tissue imaging, RV function was studied in 35 patients before and after CABG. Patients were followed-up for 1 year after the CABG. Myocardial velocities at the tricuspid annulus at the RV free wall were recorded from the apical 4-chamber views.

Results

Both the systolic and early diastolic tricuspid annular velocities (TAV) were significantly reduced 1 month after CABG (P < .001 for both). During the follow-up period, there was no improvement in the diastolic TAV. The systolic TAV showed no improvement 3 months after CABG but recovered partially 1 year after the CABG (systolic velocities were 11.8, 8.7, 8.7 and 9.7 cm/s, the early diastolic velocities were 11.0, 8.1, 8.1 and 8.2 cm/s before and 1 month, 3 months and 1 year after the CABG, respectively). The systolic and early diastolic velocities of the interventricular septum were unchanged during the follow-up period. Unlike the right ventricle, the mitral annular systolic velocity was unchanged shortly after CABG and showed signs of improvement after 1 year (6.4, 6.9, 6.8 and 7.3 cm/s respectively before and after CABG). Patients underwent dobutamine stress echocardiography (DSE) before and 3 months after the CABG. The systolic TAV increased significantly during the DSE before CABG (11.8 vs 15.8 cm/s, P < .001). However, the increase in systolic TAV was limited during DSE 3 months after CABG (8.7 vs 9.9 cm/s, P < .05).

Conclusion

RV function, as assessed by TAV, decreased significantly after CABG and the changes were still evident after 1 year. The response of systolic TAV during DSE was more pronounced before CABG than after CABG.     

A meta-analysis and systematic review of computed tomography angiography as a diagnostic triage tool for patients with chest pain presenting to the emergency department

Background  

To assess clinical utility of computed tomography angiography (CTA) in the diagnosis of chest pain patients presenting to emergency departments (EDs), we conducted a meta-analysis of CTA in patients with suspected acute coronary syndromes (ACSs).