FEASIBILITY STUDY ON EFFECT OF STRUCTURAL FLEXIBILITY OF ASYMMETRIC PRE-SWIRL STATOR ON PROPULSION PERFORMANCE FOR KRISO CONTAINER SHIP (KCS)

The use of energy-saving devices is the most effective method for decreasing CO2 emissions, which is an increasingly concerning environmental issue. The asymmetric pre-swirl stator has been developed as an energy-saving device and has been successfully applied to various types of vessels. In the present study, a flexible material was applied to an asymmetric pre-swirl stator to determine the variation in the flow around stator and its efficiency. A fluid–structure interaction (FSI) analysis system was developed using the Star-CCM+ (fluid) and the Abaqus (structure). The proposed analysis system was validated by comparing the experimental results using a flexible plate in a flowing fluid. The flexible stator was applied to a 3,600 TEU KRISO Container Ship to determine the improvement in its performance compared to the previous optimum value achieved with a rigid stator. Although this application was conducted on a model scale and the deformation was small, the results of the flexible stator indicated the possibility of not only increasing the efficiency but also decreasing the vortex risk around stator blade

Highest weight modules over quantum queer Lie superalgebra U_q(q(n))

In this paper, we investigate the structure of highest weight modules over the quantum queer superalgebra $U_q(q(n))$. The key ingredients are the triangular decomposition of $U_q(q(n))$ and the classification of finite dimensional irreducible modules over quantum Clifford superalgebras. The main results we prove are the classical limit theorem and the complete reducibility theorem for $U_q(q(n))$-modules in the category $O_q^{\geq 0}$.Comment: Definition 1.5 and Definition 6.1 are changed, and a remark is added in the new versio

Mechanism and treatment for learning and memory deficits in mouse models of Noonan syndrome.

In Noonan syndrome (NS) 30-50% of subjects show cognitive deficits of unknown etiology and with no known treatment. Here, we report that knock-in mice expressing either of two NS-associated mutations in Ptpn11, which encodes the nonreceptor protein tyrosine phosphatase Shp2, show hippocampal-dependent impairments in spatial learning and deficits in hippocampal long-term potentiation (LTP). In addition, viral overexpression of an NS-associated allele PTPN11(D61G) in adult mouse hippocampus results in increased baseline excitatory synaptic function and deficits in LTP and spatial learning, which can be reversed by a mitogen-activated protein kinase kinase (MEK) inhibitor. Furthermore, brief treatment with lovastatin reduces activation of the GTPase Ras-extracellular signal-related kinase (Erk) pathway in the brain and normalizes deficits in LTP and learning in adult Ptpn11(D61G/+) mice. Our results demonstrate that increased basal Erk activity and corresponding baseline increases in excitatory synaptic function are responsible for the LTP impairments and, consequently, the learning deficits in mouse models of NS. These data also suggest that lovastatin or MEK inhibitors may be useful for treating the cognitive deficits in NS

A case of generalized tonic seizures related to acute myocarditis

It is challenging to clinically distinguish between convulsive syncope and true seizure. We describe a 7-year-old girl presenting with generalized tonic seizure caused by acquired complete atrioventricular block related to acute myocarditis. After hospitalization following 6 episodes of new-onset fever with seizure, she had a short episode of abrupt complete atrioventricular block followed by another generalized tonic seizure. The concentrations of cardiac enzymes were elevated, and her echocardiogram showed a decreased left ventricular function. This case underlines the necessity of cardiac investigations in children with convulsive syncope

Transcatheter Closure of Fenestration with Detachable Coils After the Fontan Operation

We report our experience in 13 patients who underwent transcatheter closure of Fontan fenestration with the Cook® detachable coils. These patients underwent the extracardiac type Fontan operation with a short conduit fenestration (n=7) or lateral tunnel type with a punch-hole fenestration (n=6). Fenestration closure was done at the mean age of 5.1±2.4 yr, average of 32 months after the Fontan operation. We used one to three coils depending on the fenestration type, size, and residual shunt. Aortic oxygen saturations increased by an average of 5.4 (2-9)% and mean pressures in the Fontan circuit increased by an average of 2.1 (0-6) mmHg. During fol-low-up (median of 23 months), five patients (4 in extracardiac, 1 in lateral tunnel) had complete occlusion of the fenestration on echocardiography. There was no immediate or late complication. Transcatheter closure of fenestration in Fontan operation using the Cook® detachable coil is a safe and feasible technique. However, the coil was ineffective for closure of a punch-hole fenestration in the lateral tunnel type operation. In the conduit type fenestration, some modification of fenestration method instead of a short conduit for coil closure or use of new device is necessary to increase complete closure rate

Transcatheter closure of small ductus arteriosus with amplatzer vascular plug

PurposeThe purpose of this study was to share our experience of transcatheter closure of small patent ductus arteriosus (PDA) by using an Amplatzer vascular plug (AVP).MethodsWe reviewed the medical records of 20 patients who underwent transcatheter closure at Samsung Medical Center and Sejong General Hospital from January 2008 to August 2012. The size and shape of the PDAs were evaluated by performing angiograms, and the PDA size and the AVP devices size were compared.ResultsThe mean age of the patients was 54.9±45.7 months old. The PDAs were of type C (n=5), type D (n=12), and type E (n=3). The mean pulmonary end diameter of the PDA was 1.7±0.6 mm, and the aortic end diameter was 3.6±1.4 mm. The mean length was 7.3±1.8 mm. We used 3 types of AVP devices: AVP I (n=5), AVP II (n=7), and AVP IV (n=8). The ratio of AVP size to the pulmonary end diameter was 3.37±1.64, and AVP size/aortic end ratio was 1.72±0.97. The aortic end diameter was significantly larger in those cases repaired with AVP II than in the others (P=0.002). The AVP size did not significantly correlate with the PDA size, but did correlate with smaller ratio of AVP size to aortic end diameter (1.10±0.31, P=0.032).ConclusionTranscatheter closure of small PDA with AVP devices yielded satisfactory outcome. AVP II was equally effective with smaller size of device, compared to others

Fixed Subaortic Stenosis In Infants and Children

Fixed subaortic stenosis(FSS) is important because of not only obstruction but also aortic insufficiency. This study was performed to find out the characteristics and combined anomalies of FSS. Echocardiographic and clinical data were reviewed in 31 children who were diagnosed as FSS between March 1985 and February 1991 (age: 2months-12yr7months, M:F = 2:1). Cardiac defects were associated in 26(84%) and the majority of the cases were related to VSD(VSD only: 14 cases, VSD with other anomalies: 7 cases). The type of VSD was perimembranous in 86%(18/21) and subarterial in 14%(3/21). Aortic insufficiency(AO was present in 13 cases(42%) and the degree of AI was usually mild. The mean pressure gradient between the left ventricle and the aorta was 21mmHg by cardiac catheterization in 27. Operative resection was done in 20; 11 during the correction of major defects, 4 for AI, 5 for significant pressure gradient. The pathologic findings of 13 were mainly fibrosis and hypertrophied myocardium. In conclusion, because of the possible association with other cardiac defects, especially perimembranous VSD and its co~rt features, it is recommended to pay attention to the coexistence of FSS during the evaluation of cardiac defects

Outcomes of Pregnancy in Women with Congenital Heart Disease: A Single Center Experience in Korea

Pregnancy outcomes in patients with congenital heart disease have not been fully assessed in Korea. Forty-nine pregnancies that occurred in 34 women with congenital heart disease who registered at our hospital between September 1995 and April 2006 were reviewed. Spontaneous abortions occurred in two pregnancies at 6+1 and 7 weeks, and another two underwent elective pregnancy termination. One maternal death in puerperium occurred in a woman with Eisenmenger syndrome. Maternal cardiac complications were noted in 18.4%, pulmonary edema in 16.3%, symptomatic arrhythmia in 6.1%, deterioration of New York Heart Association (NYHA) functional class by ≥2 in 2.0%, and cardiac death in 2.0%. Independent predictors of adverse maternal cardiac events were an NYHA functional class of ≥3 (odds ratio [OR], 20.3), right ventricular dilation (OR, 21.2), and pulmonary hypertension (OR, 21.8). Neonatal complications occurred in 22.4% of pregnancies and included preterm delivery (16.3%), small for gestational age (12.2%), and neonatal death (2.0%). Independent predictors of adverse neonatal events were pulmonary hypertension (OR, 6.8) and NYHA functional class ≥3 (OR, 23.0). Pregnancy in women with congenital heart disease was found to be significantly associated with maternal cardiac and neonatal complications. Pre-pregnancy counseling and multidisciplinary care involving cardiologists and obstetricians are recommended for women with congenital heart disease contemplating pregnancy