146 research outputs found
Oxygen diffusion of non-stoichiometric (La, Sr)MnO3 /CERIA NANO-composite SOFC cathode
Solid oxide fuel cell (SOFC) is one of the highly efficient energy generation system, and it requires higher power density per unit volume to expand SOFC stationary market as well as vehicle. Co-sintering of stacks or cells including electrodes, electrolyte and separators is most promising approach to improve the power density significantly. Generally, cathode materials have low heat resistant temperatures, and they were easily decomposed or degraded by sintering at a high temperature which is suitable for densification of SOFC electrolytes. Cathode material of (La1-xSrx)1-yMnO3 (LSM) shows relatively highly heat resistance and preferable low-reactivity with fluorite electrolytes during sintering at high temperatures. The addition of LSM also much increased degradation temperature. However, it shows lower cathodic properties than lanthanum strontium cobaltite and lanthanum strontium cobalt ferrite because of poor oxygen ionic conduction. We thus investigate LSM/ceria nanocomposite cathode materials to improve oxygen ionic conduction.
The nanocomposite precursor powder containing LSM and lanthanum doped ceria (LDC) was synthesized by glycine method. Two stoichiometric compositions, which are stoichiometric composition (y=0) and non-stoichiometric (y=0.05), were prepared as LSM, and LDCs that were dissolved with lanthanum at various ratios were used to investigate inter-diffusion of lanthanum between LSM and LDC. The composite ratio of LSM and CeO2 was fixed at 9: 1 (molar ratio). Figure 1 shows SEM image of LSM/LDC nanocomposite sintered at 1200oC for 5 h in air. Sintering at 1200oC for 5h resulted in dense composite, and fine LDC particles were homogeneously dispersed with LSM. Lanthanum ratios of LDC and LSM in the composite were identified using XRD peak shift of LDC and magnetic properties of LSM, respectively. Electrical conductivity and oxygen diffusion coefficient were estimated with these dense composites. Oxygen diffusion coefficient were obtained by electrical conductivity relaxation method.
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The comparison of endothelial function between conduit artery and microvasculature in patients with coronary artery disease
Background: Flow-mediated dilation (FMD) and reactive hyperemia-peripheral arterial tonometry (RH-PAT) are both established modalities to assess vascular endothelial function. However, clinical significance of FMD and RH-PAT may be different because these methods measure vascular function in different vessels (conduit arteries and resistance vessels).
Methods: To elucidate differences in the clinical significance of FMD and RH-PAT, a simultaneous determination of FMD was performed and reactive hyperemia index (RHI) measured by RH-PAT in 131 consecutive patients who underwent coronary angiography for suspicion of coronary artery disease (CAD).
Results: There was no significant correlation between FMD and RHI in patients overall. When patients were divided into four groups: FMD ≥ 6%/RHI ≥ 1.67 group, FMD ≥ 6%/RHI < 1.67 group, FMD < 6%/RHI ≥ 1.67 group and FMD < 6%/RHI < 1.67 group, the highest incidence of multivessel CAD was seen in the FMD < 6%/RHI < 1.67 group (52%). Multiple logistic regression analysis showed that a prevalence of both FMD < 6% and RHI < 1.67 was an independent predictor of multivessel CAD (odds ratio: 4.160, 95% confidence interval: 1.505–11.500, p = 0.006). RHI was negatively correlated with the baseline vessel diameter (R = –0.268, p = 0.0065) and maximum vessel diameter (R = –0.266, p = 0.0069) in patients with FMD < 6%, whereas these correlations were absent in patients with FMD ≥ 6%.
Conclusions: Present results suggest that noninvasive assessment of vascular endothelial functions provide pathophysiological information on both conduit arteries and resistance vessels in patients with CAD
Effect of high-fat diet on phosphorus absorption
Objective: Dietary carbohydrate/fat ratio may affect phosphorus metabolism because both calcium and phosphorus are regulated by similar metabolic mechanisms, and a high-fat diet (HF) induces deleterious effects on the absorption of dietary calcium. We hypothesized that the HF induces an increase in phosphorus absorption; therefore, this study aimed to evaluate the effects of differences in the quantity and quality of dietary fat on phosphorus metabolism over the short and long term.
Research Methods & Procedures: Eighteen 8-week-old Sprague-Dawley male rats were fed an isocaloric diet containing varied carbohydrate/fat energy ratio and sources of fat (control diet [Control], HF, and high saturated-fat diet [HF-SFA]). At 3 days and 7 weeks after the allocation and initiation of the test diets, feces and urine were collected and used for phosphorus and calcium measurement.
Results: The fecal phosphorous concentration (F-Pi) was lower in the HF-SFA group than in the other two groups; however, the urine phosphorus concentration (U-Pi) was significantly higher in the HF-SFA group than the other two groups when the rats were fed over the short (p<0.01) and long term (p<0.01 vs Control group, p<0.05 vs HF group). There were no significant differences in type-IIa sodium-phosphate cotransporter (NaPi-2a) and type-IIc sodium-phosphate cotransporter (NaPi-2c) mRNA expression, which are renal phosphate transport-related genes; however, the expression of type-IIb sodium-phosphate cotransporter (NaPi-2b) and type-III sodium-phosphate cotransporter (Pit-1) mRNA in the duodenum was higher in the HF and HF-SFA groups than in the Control group (p<0.05), although there were no significant differences in these in the jejunum.
Conclusions: Our results indicated that HF, particularly HF-SFA, increases intestinal phosphate absorption compared with Control
Local Release of C-Reactive Protein From Vulnerable Plaque or Coronary Arterial Wall Injured by Stenting
ObjectivesThe purpose of this study was to assess local release of C-reactive protein (CRP) from atherosclerotic plaques or the vessel wall injured by stenting.BackgroundRecent research has focused on the local production of CRP, especially in inflammatory atherosclerotic plaques.MethodsThe study consisted of two separate protocols. In protocol 1, we measured serum high-sensitivity-CRP (hs-CRP) levels in coronary arterial blood sampled just distal and proximal to the culprit lesions in 36 patients with stable angina and 13 patients with unstable angina. In protocol 2, we measured serial serum hs-CRP levels and activated Mac-1 on the surface of neutrophils in both coronary sinus and peripheral blood in 20 patients undergoing coronary stenting.ResultsIn protocol 1, CRP was higher in distal blood than proximal blood in both stable (p < 0.05) and unstable angina (p < 0.01). The translesional CRP gradient (distal CRP minus proximal CRP, p < 0.05) as well as the proximal CRP (p < 0.05) and distal CRP (p < 0.05) was higher in unstable angina than in stable angina. In protocol 2, the transcardiac CRP gradient (coronary sinus minus peripheral blood) and activated Mac-1 increased gradually after stenting, reaching a maximum at 48 h (p < 0.001 vs. baseline for both). There was a positive correlation between the transcardiac CRP gradient and activated Mac-1 at 48 h (r = 0.45, p < 0.01).ConclusionsC-reactive protein is an excellent marker for plaque instability or poststent inflammatory status, and its source might be the inflammation site of the plaque or the coronary arterial wall injured by stenting
Inter-assay variability of next-generation sequencing-based gene panels
BACKGROUND: Tumor heterogeneity has been known to cause inter-assay discordance among next-generation sequencing (NGS) results. However, whether preclinical factors such as sample type, sample quality and analytical features of gene panel can affect the concordance between two different assays remains largely unexplored. METHODS: Replicate sets of DNA samples extracted from formalin-fixed paraffin-embedded tissues (FFPE) (n = 20) and fresh frozen (FF) tissues (n = 10) were herein analyzed using a tumor-only (TO) and paired tumor-normal (TN) gene panel in laboratories certified by the Clinical Laboratory Improvement Amendment. Reported variants from the TO and TN panels were then compared. Furthermore, additional FFPE samples were sequentially sliced from the same FFPE block and submitted to another TN panel assay. RESULTS: Substantial discordance (71.8%) was observed between the results of the two panels despite using identical DNA samples, with the discordance rate being significantly higher for FFPE samples (p < 0.05). Among the 99 variants reported only in the TO panel, 32.3% were consistent with germline variants, which were excluded in the TN panel, while 30.3% had an allele frequency of less than 5%, some of which were highly likely to be artificial calls. The comparison of two independent TN panel assay results from the same FFPE block also showed substantial discordance rate (55.3%). CONCLUSIONS: In the context of clinical settings, our comparative analysis revealed that inter-NGS assay discordance commonly occurred due to sample types and the different analytical features of each panel
Clinical Incidence of Sacroiliac Joint Arthritis and Pain after Sacropelvic Fixation for Spinal Deformity
∙ The authors have no financial conflicts of interest. © Copyright: Yonsei University College of Medicine 2012 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens
Identification of five genetic variants as novel determinants of type 2 diabetes mellitus in Japanese by exome-wide association studies
We performed exome-wide association studies to identify single nucleotide polymorphisms that either influence fasting plasma glucose level or blood hemoglobin A1c content or confer susceptibility to type 2 diabetes mellitus in Japanese. Exome-wide association studies were performed with the use of Illumina Human Exome-12 DNA Analysis or Infinium Exome-24 BeadChip arrays and with 11,729 or 8635 subjects for fasting plasma glucose level or blood hemoglobin A1c content, respectively, or with 14,023 subjects for type 2 diabetes mellitus (3573 cases, 10,450 controls). The relation of genotypes of 41,265 polymorphisms to fasting plasma glucose level or blood hemoglobin A1c content was examined by linear regression analysis. After Bonferroni’s correction, 41 and 17 polymorphisms were significantly (P < 1.21 × 10−6) associated with fasting plasma glucose level or blood hemoglobin A1c content, respectively, with two polymorphisms (rs139421991, rs189305583) being associated with both. Examination of the relation of allele frequencies to type 2 diabetes mellitus with Fisher’s exact test revealed that 87 polymorphisms were significantly (P < 1.21 × 10−6) associated with type 2 diabetes mellitus. Subsequent multivariable logistic regression analysis with adjustment for age and sex showed that four polymorphisms (rs138313632, rs76974938, rs139012426, rs147317864) were significantly (P < 1.44 × 10−4) associated with type 2 diabetes mellitus, with rs138313632 and rs139012426 also being associated with fasting plasma glucose and rs76974938 with blood hemoglobin A1c. Five polymorphisms—rs139421991 of CAT, rs189305583 of PDCL2, rs138313632 of RUFY1, rs139012426 of LOC100505549, and rs76974938 of C21orf59—may be novel determinants of type 2 diabetes mellitus
Complete Response Using Sorafenib Monotherapy for Advanced Hepatocellular Carcinoma with Multiple Lymph Node and Bone Metastases: A Case Report
Hepatocellular carcinoma(HCC)is the sixth most commonly diagnosed cancer worldwide. Sorafenib is an oral multikinase inhibitor used in the palliative treatment of advanced HCC. However, there were no reported cases of complete response(CR)from two previous large phaseⅢ clinical trials. Here, we report a case of CR in a patient with advanced HCC with multiple lymph node and bone metastases, treated with sorafenib monotherapy for 8 months. To our knowledge, this is the first evidence showing CR following sorafenib monotherapy for HCC with bone metastasis
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