Bidirectional propagation of tilting domain walls in perpendicularly magnetized T shaped structure with the interfacial Dzyaloshinskii-Moriya interaction

Understanding of domain wall (DW) propagation in a complex structure is an essential first step toward the development of any magnetic-domain based devices including spin-based logic or magnetic memristors. Interfacial Dzyaloshinskii-Moriya interaction (iDMI) in the structure with broken inversion symmetry induces an asymmetrical DW configuration with respect to the direction of in-plane field. Dynamic behaviors of field-driven DW within the film with perpendicular magnetic anisotropy is influenced by DW tilt from the iDMI effect and the corners in the T-shaped structure of the DW path. Images from Kerr microscopy reveal that the iDMI effective field contributes to a tilted structure of DW configuration and evolution along its propagation. With the combination of iDMI and T-shaped structure, we observed two distinguished bidirectional DW propagations in two output branches and distinct arriving times at the destination pads with a uniform external field. Micromagnetic simulation results is compared with the observed dynamics of a DW configuration in the structure providing an additional confirmation of the interpreted results.

Comparison of genetic diversity between wild-caught broodstock and hatchery-produced offspring populations of the vulnerable Korean kelp grouper (Epinephelus bruneus) by microsatellites

The kelp grouper Epinephelus bruneus (Perciformes: Haemulidae), is one of the most economically important fishery resources in Korea. This fish is regarded as a target for prospective aquaculture diversification; therefore, maintenance of stock quality is important. To investigate the effects of current artificial reproduction in a hatchery facility, genetic variation in wild-caught broodstock and hatchery-produced offspring of kelp grouper was analyzed using eight polymorphic nuclear microsatellite DNA loci; 77 alleles were identified. Allelic variability ranged from 2 to 22 in the broodstock and from 1 to 10 in the offspring. The average observed and expected heterozygosities were 0.620 and 0.623 in the broodstock and 0.600 and 0.513 in the offspring, respectively. The possibility of a recent genetic bottleneck was suggested in both populations of E. bruneus. The minor, but significant, genetic differentiation (FST = 0.047, P < 0.05) observed was mainly due to statistically significant reductions in the number of alleles in the offspring compared with the broodstock, suggesting that these genetic changes could be related to genetic drift. Our results demonstrate the usefulness of microsatellite markers to monitor genetic variation and raise concerns about potential harmful genetic effects of inappropriate hatchery procedures. Therefore, genetic variation between broodstock and offspring in a hatchery should be monitored in both breeding and release programs as a routine hatchery operation, and inbreeding should ideally be controlled to improve kelp grouper hatchery management. Our data provide a useful genetic basis for future planning of sustainable culture and management of E. bruneus in fisheries.

Splenic vein thrombosis and pancreatic fistula after minimally invasive distal pancreatectomy

BACKGROUND

This study aimed to investigate the clinical relevance of splenic vein thrombosis (SVT) in the splenic vein remnant following minimally invasive distal pancreatosplenectomy (DPS).

METHODS

Medical records of patients who underwent laparoscopic or robotic distal pancreatectomy (DP) with or without splenectomy between January 2006 and August 2012 were reviewed. Rates of SVT and clinically relevant postoperative pancreatic fistula (POPF) were compared in a group of patients undergoing DPS and a group having spleen-preserving DP.

RESULTS

Seventy-nine patients had minimally invasive DP, of whom 38 (48 per cent) developed SVT in the splenic vein remnant. DPS was associated with POPF (P = 0.001) and SVT (P < 0.001). SVT length was closely related to the amount of peripancreatic fluid collection (P = 0.025) and POPF (P = 0.045). In a comparison of splenic vessel-sacrificing, spleen-preserving DP and DPS, postoperative platelet count was significantly higher in the DPS group (P < 0.001). In addition, grade of SVT (P = 0.092) and POPF (P = 0.065) tended to be associated with DPS, suggesting that SVT may be related to both splenectomy and POPF.

CONCLUSION

Minimally invasive DPS is associated with SVT and POPF. Preservation of the spleen should be considered when treating patients with benign and borderline malignant tumours of the distal pancreas.

Influence of sintering temperature on the microstructure and thermoelectric properties of polycrystalline Fe1.9925P0.0075O3

The solution combustion process is used to synthesize Fe1.9925P0.0075O3 nano-powders. The sintered Fe1.9925P0.0075O3 bodies are alpha-Fe2O3-based single phase with the rhombohedral structure. The electrical conductivity increases with an increase in sintering temperature because of an increase in grain size and density. The absolute value of the Seebeck coefficient escalates with an increase in sintering temperature up to 1000 degrees C, and then decreases with a further rise in its sintering temperature. The Fe1.9925P0.0075O3 sintered at 1000 degrees C shows the highest power factor, i.e., 1.39 x 10(-5) W m(-1) K(-2) at 700 degrees C.

Improvement in high-temperature thermoelectric properties by adding Mn for Co in Ca3Co4O9

Nano-sized Ca3Co(4-x)Mn(x)O9 (0 < or = x < or = 0.6) thermoelectric powders were synthesized by solution combustion method, using aspartic acid as fuel. The microstructure and high-temperature (500-800 degrees C) thermoelectric properties of the Ca3Co(4-x)Mn(x)O9 were investigated. The addition of Mn for Co in Ca3Co(4-x)Mn(x)O9 resulted in a decrease of the electrical conductivity and a significant increase of the Seebeck coefficient. Consequently, the power factor was remarkably enhanced by the addition of Mn. Ca3Co(3.7)Mn(0.3)O9 sample showed the highest value of the power factor (1.24 x 10(-4) Wm(-1) K(-2)) at 800 degrees C. We believe that the Ca3Co(4-x)Mn(x)O9 is strongly desirable as a novel high-temperature thermoelectric material for power generation.

Synthesis of nanocrystalline Ce(0.8)Gd(0.2)O(2-delta) electrolyte materials for IT-SOFC

We successfully synthesized nano-sized Ce(0.8)Gd(0.2)O(2-delta) powders by combustion method, using gelatin as fuel. The calcined powders showed high-quality characteristics, i.e., nano-scale size (14-35 nm) and narrow size distribution. The structural, morphological, and electrical characteristics of the sintered Ce(0.8)Gd(0.2)O(2-delta) were studied systematically, depending on sintering temperature. The crystal structure of the Ce(0.8)Gd(0.2)O(2-delta) belonged to the cubic fluorite structure. The gelatin-assisted combustion synthesized Ce(0.8)Gd(0.2)O(2-delta) powders allowed to sinter well at low temperature for dense and ultra-fine Ce(0.8)Gd(0.2)O(2-delta) electrolyte with good electrical conductivity. The sintering temperature of the Ce(0.8)Gd(0.2)O2 powder was approximately 300 degrees C lower than that of conventional solid-state synthesized powder. The nanopowder produced was sintered into pellets with relative densities over 99.1% of the theoretical value even at 1400 degrees C. The Ce(0.8)Gd(0.2)O(2-delta) sintered at 1400 degrees C exhibited a conductivity of 0.101 S/cm at 800 degrees C in air.

Electrical properties of nanocrystalline Ce(0.8)Sm(0.2)O(2-delta) and Ce(1-x)Gd(x)O(2-delta) (0.1 < or = x < or = 0.3) ceramics for IT-SOFC

Ce(0.8)Sm(0.2)O(2-delta) and Ce(1-x)Gd(x)O(2-delta) (0.1 < or = x < or = 0.3) nano-sized powders were successfully synthesized by the solution combustion synthesis process. The calcined nanopowders showed a ceria-based single phase with a cubic fluorite structure. In this study, we discussed the structural and electrical characteristics of the sintered Ce(0.8)Sm(0.2)O(2-delta) and Ce(1-x)Gd(x)O(2-delta). We obtained high-quality Ce(0.8)Sm(0.2)O(2-delta) and Ce(1-x)Gd(x)O(2-delta) ceramics with a high density, ultra-fine grain size, and high electrical conductivity even at low sintering temperature using the nanosized powders. The electrical conductivities at 800 degrees C for the Ce(0.8)Sm(0.2)O(2-delta) sintered at 1400 degrees C and the Ce(0.8)Gd(0.2)O(2-delta) sintered at 1350 degrees C were 0.110 and 0.104 Scm(-1), respectively.

Pathogens in the middle ear effusion of children with persistent otitis media: implications of drug resistance and complications

Acute otitis media (AOM) is the most common disease for which pediatricians prescribe antimicrobial agents. Middle ear fluid were collected from 243 children with AOM that failed to respond to a previous course of antimicrobial therapy and who had then received myringotomy from September 1997 through August 1999. Bacterial cultures were done and antimicrobial susceptibilities were analyzed. Streptococcus pneumoniae (21.8%) was the most common causative organism, followed by Haemophilus influenzae (10.2%), Staphylococcus aureus (7%), and Pseudomonas aeruginosa (1.8%), while Moraxella catarrhalis (0.7%) and group A beta-hemolytic streptococcus (0.2%) were rarely isolated. In patients whose condition failed to improve after a course of antibiotic treatment, drug resistance became a serious problem. Fourteen percent of the patients in this series had complications, which included recurrent AOM, persistent middle ear effusion necessitating ventilation tube insertion, hearing impairment, mastoiditis, meningitis, chronic otitis media, brain abscess, and sepsis. Possible risk factors such as young age, male sex, underlying diseases, and a culture of S. pneumoniae or H. influenzae were not significantly associated with an increased incidence of complications. More stringent diagnosis and the correct choice of antibiotic treatment combined with the introduction of potential virus and bacterial vaccines are promising ways to reduce the morbidity of AOM in children.

Metabolic disturbance in obese children: glucose, insulin levels and lipid profile

Obesity is a common nutritional disorder among children and adolescents. The purpose of this study was to investigate the biochemical changes in obese children in Taiwan, in comparison with those observed by other authors. Children with weights above 120 percent of ideal body weight were considered obese. Serum glucose, insulin, uric acid, and creatinine levels and lipid profiles of 298 obese children (mean age 11.3 +/- 2.4 years, 158 boys) and 60 controls (mean age 11.6 +/- 2.2 years, 38 boys) were determined using accepted procedures. Demographic and serum biochemical characteristics were compared between obese and control groups overall and by gender. Serum glucose, insulin, cholesterol, and triglyceride levels, known risk factors for coronary heart disease, were higher in the obese patients than in the control group. Early treatment and prevention of childhood obesity may keep the metabolic disturbance from deteriorating and becoming risk factors for coronary heart disease.

Differential and constitutive expression of neuronal, inducible, and endothelial nitric oxide synthase mRNAs and proteins in pathologically normal human tissues

Nitric oxide (NO) is produced by NO synthases (nNOS, iNOS, and eNOS) expressed in various human tissues and depending on the amount of NO produced in each tissue, the physiological function of NO is determined. However, due to the difficulty in obtaining normal human tissues, little is known about the basal levels of each of the three NOS mRNAsand proteins expressed constitutively in various human tissues. Results of the present study indicate that the basal levels of each of the three NOS mRNAs and proteins expressed in various regions of brain and peripheral tissues are different both in their sizes and in their contents. In Northern blot analysis, two different-sized mRNAs were found for each NOS isozymes: for the nNOS, approximately 12 and <12 kb mRNAs; for the iNOS, 4.2 and 4.5 kb mRNAs; for the eNOS, 4.2 and 4.4 kb mRNAs. In the Western blot, several different-sized NOS proteins were detected ( approximately 160, approximately 140, and approximately 130 kDa for nNOS; approximately 130 kDa for iNOS and eNOS) with tissue-specific expression patterns. These differential expression patterns of NOS mRNAs and proteins were caused by alternative splicing in the open-reading frame, and 5'- and/or 3'-untranslated regions of NOS mRNAs. These results suggest that regulation for differential expression of the three NOS genes in various human tissues may occur by alternative splicing of the NOS mRNAs in tissue-specific patterns.

Gene dosage affects the cardiac and brain phenotype in nonmuscle myosin II-B-depleted mice

Complete ablation of nonmuscle myosin heavy chain II-B (NMHC-B) in mice resulted in cardiac and brain defects that were lethal during embryonic development or on the day of birth. In this paper, we report on the generation of mice with decreased amounts of NMHC-B. First, we generated B(DeltaI)/B(DeltaI) mice by replacing a neural-specific alternative exon with the PGK-Neo cassette. This resulted in decreased amounts of NMHC-B in all tissues, including a decrease of 88% in the heart and 65% in the brain compared with B(+)/B(+) tissues. B(DeltaI)/B(DeltaI) mice developed cardiac myocyte hypertrophy between 7 months and 11 months of age, at which time they reexpressed the cardiac beta-MHC. Serial sections of B(DeltaI)/B(DeltaI) brains showed abnormalities in neural cell migration and adhesion in the ventricular wall. Crossing B(DeltaI)/B(DeltaI) with B(+)/B(-) mice generated B(DeltaI)/B(-) mice, which showed a further decrease of approximately 55% in NMHC-B in the heart and brain compared with B(DeltaI)/B(DeltaI) mice. Five of 8 B(DeltaI)/B(-) mice were born with a membranous ventricular septal defect. Moreover, 5 of 5 B(DeltaI)/B(-) mice developed myocyte hypertrophy by 1 month; B(DeltaI)/B(-) mice also reexpressed the cardiac beta-MHC. More than 60% of B(DeltaI)/B(-) mice developed overt hydrocephalus and showed more severe defects in neural cell migration and adhesion than did B(DeltaI)/B(DeltaI) mice. These data on B(DeltaI)/B(DeltaI) and B(DeltaI)/B(-) mice demonstrate a gene dosage effect of the amount of NMHC-B on the severity and time of onset of the defects in the heart and brain.

Isolated left main coronary ostial stenosis: intraoperative transesophageal echocardiography during surgical angioplasty

OBJECTIVE

We hypothesized that transesophageal echocardiography could be used to image the repair of a left ostium or main coronary artery following surgical angioplasty.

METHODS AND RESULTS

Six patients, all women, were found to have isolated left main coronary ostial stenosis. We performed preoperative transesophageal echocardiography (TEE) in three and intraoperative TEE in four of six patients. Their mean age was 48 years. They presented with severe angina (Class III or IV) with a short duration (6.8 +/- 7.8 months). They had a low incidence of risk factors while histopathologic examinations showed typical atherosclerosis in all four patients. Preoperative two-dimensional echocardiography demonstrated left main coronary ostial stenosis in three patients. We clearly observed the patency of the pericardial or saphenous venous patch with basal short-axis scan on two-dimensional and color Doppler echocardiography in all four patients after weaning them from cardiopulmonary bypass and finished operation without complications.

CONCLUSIONS

Our study shows that TEE can be used to image the repair of a left ostium or main coronary artery following surgical angioplasty and provide the surgeon with the required information about the adequacy of the repair.

Isolated left main coronary ostial stenosis in Oriental people: operative, histopathologic and clinical findings in six patients

OBJECTIVES

This study was performed to determine whether there are differences in the operative, histopathologic, angiographic and clinical findings of isolated ostial stenosis between Oriental and western patients.

BACKGROUND

Angiographic, clinical and histologic findings in isolated ostial stenosis have been reported in western but not in Oriental patients.

METHODS

Six patients, all women (0.88% of a total of 684 patients who underwent coronary angiography between March 1989 and July 1991), were found to have isolated left main coronary ostial stenosis. We performed surgical ostial angioplasty with the autologous pericardial or saphenous venous patch and biopsy at the aortic arteriotomy site in four of the six patients.

RESULTS

All six patients presented with severe angina (angina class III or IV) of short duration (mean +/- SD 6.2 +/- 6.2 months) and had a very low incidence of risk factors, although histopathologic examination showed typical atherosclerosis in four of the six patients. They were young to middle-aged women (mean 45 +/- 3 years) except for Patient 6 (62 years). Exercise duration was short and ST segment depression, accompanied by typical angina, was observed in many leads in the warm-up period or stage I. Despite the crucial location of the lesion, most patients had well preserved left ventricular function and normal wall motion. There was no angiographically definable collateral circulation from either ipsilateral or contralateral vessels except for grade I collateral circulation in Patient 5. Operative findings demonstrated mostly yellow atheroma in the aortic wall and left coronary ostium. Coronary angiography showed only ostial stenosis of the left coronary artery in all six patients, but operative findings documented atheromatous change in the left main coronary artery in two of the six.

CONCLUSIONS

The clinical, angiographic, histopathologic and operative findings of Oriental patients were similar to those reported in western patients, but the incidence of isolated left main coronary ostial stenosis was higher in the Oriental group. Angiographically definable isolated coronary ostial stenosis may often not be true isolated ostial stenosis.