151 research outputs found
Mechanical Properties and Durability of Latex-Modified Fiber-Reinforced Concrete: A Tunnel Liner Application
This study assessed the mechanical properties and durability of latex-modified fiber-reinforced segment concrete (polyolefin-based macrosynthetic fibers and hybrid fiber-macrosynthetic fiber and polypropylene fiber) for a tunnel liner application. The tested macrosynthetic fiber-reinforced concrete has a better strength than steel fiber-reinforced concrete. The tested concrete with blast furnace slag has a higher chloride ion penetration resistance (less permeable), but its compressive and flexural strengths can be reduced with blast furnace slag content increase. Also, the hybrid fiber-reinforced concrete has higher compressive strength, flexural strength, chloride ion water permeability resistance, impact resistance, and abrasion resistance than the macrosynthetic fiber-reinforced concrete. The modified fiber improved the performance of concrete, and the hybrid fiber was found to control the formation of micro- and macrocracks more effectively. Therefore, overall performance of the hybrid fiber-reinforced concrete was found superior to the other fiber-reinforced concrete mixes tested for this study. The test results also indicated that macrosynthetic fiber could replace the steel fiber as a concrete reinforcement
Fibrinogen gamma-A chain precursor in CSF: a candidate biomarker for Alzheimer's disease
<p>Abstract</p> <p>Background</p> <p>Cerebrospinal fluid (CSF) may be valuable for exploring protein markers for the diagnosis of Alzheimer's disease (AD). The prospect of early detection and treatment, to slow progression, holds hope for aging populations with increased average lifespan. The aim of the present study was to investigate candidate CSF biological markers in patients with mild cognitive impairment (MCI) and AD and compare them with age-matched normal control subjects.</p> <p>Methods</p> <p>We applied proteomics approaches to analyze CSF samples derived from 27 patients with AD, 3 subjects with MCI and 30 controls. The AD group was subdivided into three groups by clinical severity according to clinical dementia rating (CDR), a well known clinical scale for dementia.</p> <p>Results</p> <p>We demonstrated an elevated level of fibrinogen gamma-A chain precursor protein in CSF from patients with mild cognitive impairment and AD compared to the age-matched normal subjects. Moreover, its expression was more prominent in the AD group than in the MCI and correlated with disease severity and progression. In contrast, fibrinogen gamma-A chain precursor protein was detected very low in the age-matched normal group.</p> <p>Conclusion</p> <p>These findings suggest that the CSF level of fibrinogen gamma-A chain precursor may be a candidate biomarker for AD.</p
Reversible switching of leukemic cells to a drug-resistant, stem-like subset via IL-4-mediated cross-talk with mesenchymal stroma
Chemoresistance of leukemic cells has largely been attributed to clonal evolution secondary to accumulating mutations. Here, we show that a subset of leukemic blasts in contact with the mesenchymal stroma undergo cellular conversion into a distinct cell type that exhibits a stem cell-like phenotype and chemoresistance. These stroma-induced changes occur in a reversible and stochastic manner driven by cross-talk, whereby stromal contact induces interleukin-4 in leukemic cells that in turn targets the mesenchymal stroma to facilitate the development of new subset. This mechanism was dependent on interleukin-4-mediated upregulation of vascular cell adhesion molecule- 1 in mesenchymal stroma, causing tight adherence of leukemic cells to mesenchymal progenitors for generation of new subsets. Together, our study reveals another class of chemoresistance in leukemic blasts via functional evolution through stromal cross-talk, and demonstrates dynamic switching of leukemic cell fates that could cause a non-homologous response to chemotherapy in concert with the patient-specific microenvironment
A study on nutrition knowledge and dietary behavior of elementary school children in Seoul
The purpose of this study was to investigate the nutrition and diet related knowledge, attitude, and behavior of elementary school children in Seoul. The subjects included were 439 (male 236, female 203) elementary school children in the 4th to the 6th grades. The statistical analysis was conducted using SPSS 12.0 program. The average obesity index (OI) was 104.98 and 99.82 for male and female subjects, respectively. The average percentage of underweight, normal, overweight and obese of subjects was 33.7%, 32.8%, 12.3%, and 19.4%, respectively. The percentage of the underweight group of female subjects was higher than that of the male subjects. The percentage of the obese group of male subjects was higher than that of the female subjects. The average score of nutrition knowledge, nutrition attitude and dietary behavior was 6.8, 7.44, and 7.34, respectively. Dietary behavior of male subjects was positively correlated with parents' education levels, monthly household income and nutrition attitude. Dietary behavior of female subjects was positively correlated with monthly household income, nutrition knowledge and nutrition attitude. Dietary behavior of female subjects was positively correlated with obesity index (OI). Proper nutrition education and intervention are required for the improvement of elementary school children's nutrition knowledge, nutrition attitudes and dietary behaviors
Anti-Wrinkle Effect of Magnesium Lithospermate B from Salvia miltiorrhiza BUNGE: Inhibition of MMPs via NF-kB Signaling
Skin is in direct contact with the environment and therefore undergoes aging as a consequence of environmentally induce damage. Wrinkle formation is a striking feature of intrinsic and photo-induced skin aging, which are both associated with oxidative stress and inflammatory response. The present study was undertaken to identify the mechanisms responsible for the anti-wrinkle effects of MLB, and thus, we investigated whether magnesium lithospermate B (MLB) from Salvia miltiorrhiza BUNGE associated with wrinkle formation caused by intrinsic and extrinsic skin aging using Sprague-Dawley rats aged 5 and 20 months and ultraviolet B (UVB)-irradiated human skin fibroblasts cells, respectively. The results obtained showed that the oral administration of MLB significantly upregulated the level of type I procollagen and downregulated the activities and expressions of matrix-metalloproteinases (MMPs) in rat skin. In fibroblasts, MLB suppressed the transactivation of nuclear factor-kB (NF-kB) and activator protein 1(AP-1), which are the two transcription factors responsible for MMP expression, by suppressing oxidative stress and the mitogen activated protein kinase (MAPK) pathway. Our results show that the antioxidant effect of MLB is due to the direct scavenging of reactive oxygen species (ROS) and its inhibitory effects on NF-kB-dependent inflammation genes, such as, cyclooxygenase-2 and inducible nitric oxide synthase. MLB was found to reverse both age- and UVB-related reductions in skin procollagen levels by suppressing the expressions and activities of NF-kB and AP-1-dependent MMPs by modulating ROS generation and the MAPK signaling pathway. We suggest that MLB potentially has anti-wrinkle and anti-skin aging effects
Thermally modulated multilayered graphene oxide for hydrogen storage
We have obtained high pressure H(2) isotherms with respect to the interlayer distance of multilayered graphene oxide (GO) modulated by thermal annealing. The maximum storage capacity is 4.8 (0.5) wt% at 77 K (298 K) and at 9.0 MPa pressure. We found the optimum GO interlayer distance for maximum H2 uptake at 6.5 angstrom, similar to the predicted distances from first-principles calculations for graphite materials. Our results reveal that multilayered GO can be a practical material of choice to allow the use of graphene as a hydrogen storage material, provided that only small amounts of O and OH functional groups exist as spacers on GO sheets.close171
A Case of Cardiac Cephalalgia Showing Reversible Coronary Vasospasm on Coronary Angiogram
Background Under certain conditions, exertional headaches may reflect coronary ischemia Case Report A 44-year-old woman developed intermittent exercise-induced headaches with chest tightness over a period of 10 months Cardiac catheterization followed by acetylcholine provocation demonstrated a right coronary artery spasm with chest tightness, headache, and ischemic effect of continuous electrocardiography changes The patient`s headache disappeared following ultra-arterial nitroglycerine injection Conclusions A coronary angiogram with provocation study revealed variant angina and cardiac cephalalgia, as per the International Classification of Headache Disorders (code 10 6) We report herein a patient with cardiac cephalalgia that manifested as reversible coronary vasospasm following an acetylcholine provocation test J Clin Neurol 2010;6:99-101*INT HEAD SOC HEAD, 2004, CEPHALALGIA S1, V24, P1, DOI DOI 10.1111/J.1468-2982.2004.00653.XChen SP, 2004, EUR NEUROL, V51, P221, DOI 10.1159/000078489Martinez HR, 2002, HEADACHE, V42, P1029Lanza GA, 2000, LANCET, V356, P998Lance JW, 1998, HEADACHE, V38, P315Lipton RB, 1997, NEUROLOGY, V49, P813Grace A, 1997, CEPHALALGIA, V17, P195BOWEN J, 1993, HEADACHE, V33, P238MELLER ST, 1992, NEUROSCIENCE, V48, P501VERNAY D, 1989, HEADACHE, V29, P350LEFKOWITZ D, 1982, ARCH NEUROL-CHICAGO, V39, P130
Impact of a multidomain lifestyle intervention on white matter integrity: the SUPERBRAIN exploratory sub-study
In the South Korean study to prevent cognitive impairment and protect BRAIN health through lifestyle intervention in at-risk elderly people (SUPERBRAIN), we evaluated the impact of a 24-week facility-based multidomain intervention (FMI) and home-based MI (HMI) on white matter integrity. Among 152 participants, aged 60–79 years without dementia but with ≥1 modifiable dementia risk factor, 19 FMI, 20 HMI, and 16 controls underwent brain MRI at baseline and 24 weeks. Between the intervention and control groups, we compared changes in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) at regions-of-interest (ROI) including the cingulum cingulate gyrus (CgC), cingulum hippocampus (CgH), superior longitudinal fasciculus (SLF), as well as the uncinate fasciculus (UF). In addition, correlations between total and standard scores cognitive domains of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) or serum brain-derived neurotrophic factor (BDNF) and changes in brain image measures were evaluated at a statistical significance level of p < 0.05 (uncorrected for multiple corrections). The FA, MD, AD, and RD at each ROI at the baseline were not different among groups after Bonferroni correction. In the statistical analysis using two-way repeated measures ANOVA, any significant difference in longitudinal changes in the FA, MD, AD, and RD was not revealed. The statistical analysis, among the significant regions in paired t-test of the intervention group, compared with the control group, the FMI, HMI, and intervention group yielded significantly more beneficial effects on the AD of the CgC. In addition, longitudinal AD changes of the left CgC correlated with the BDNF changes (r = 0.280, p = 0.048). In this study, enhanced cognitive reserve after the multidomain lifestyle intervention could be revealed by changes in brain imaging for white matter integrity
Gene Expression Pattern in Transmitochondrial Cytoplasmic Hybrid Cells Harboring Type 2 Diabetes-Associated Mitochondrial DNA Haplogroups
Decreased mitochondrial function plays a pivotal role in the pathogenesis of type 2 diabetes mellitus (T2DM). Recently, it was reported that mitochondrial DNA (mtDNA) haplogroups confer genetic susceptibility to T2DM in Koreans and Japanese. Particularly, mtDNA haplogroup N9a is associated with a decreased risk of T2DM, whereas haplogroups D5 and F are associated with an increased risk. To examine functional consequences of these haplogroups without being confounded by the heterogeneous nuclear genomic backgrounds of different subjects, we constructed transmitochondrial cytoplasmic hybrid (cybrid) cells harboring each of the three haplogroups (N9a, D5, and F) in a background of a shared nuclear genome. We compared the functional consequences of the three haplogroups using cell-based assays and gene expression microarrays. Cell-based assays did not detect differences in mitochondrial functions among the haplogroups in terms of ATP generation, reactive oxygen species production, mitochondrial membrane potential, and cellular dehydrogenase activity. However, differential expression and clustering analyses of microarray data revealed that the three haplogroups exhibit a distinctive nuclear gene expression pattern that correlates with their susceptibility to T2DM. Pathway analysis of microarray data identified several differentially regulated metabolic pathways. Notably, compared to the T2DM-resistant haplogroup N9a, the T2DM-susceptible haplogroup F showed down-regulation of oxidative phosphorylation and up-regulation of glycolysis. These results suggest that variations in mtDNA can affect the expression of nuclear genes regulating mitochondrial functions or cellular energetics. Given that impaired mitochondrial function caused by T2DM-associated mtDNA haplogroups is compensated by the nuclear genome, we speculate that defective nuclear compensation, under certain circumstances, might lead to the development of T2DM
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