988 research outputs found

    Pseudo-gap features of intrinsic tunneling in (HgBr_2)-Bi2212 single crystals

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    The c-axis tunneling properties of both pristine Bi2212 and its HgBr2_2 intercalate have been measured in the temperature range 4.2 - 250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the c\it c-axis direction have been observed. The dynamic conductance dI/I/dV(V)V(V) shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, followed by a wide maximum, which persists up to a room temperature. Shape of the temperature dependence of the {\it c}-axis resistance does not change after the intercalation suggesting that a coupling between CuO2\rm CuO_2-bilayers has little effect on the pseudogap.Comment: 6 pages, 5 figures; presented at the Second Int Conf. New3Sc-1999 (Las Vegas, NV

    Improved performance of polymer light-emitting diodes with nanocomposites

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    The characteristics of a hybrid polymer light-emitting diode (HPLED) with an active layer of poly [2-methoxy,5-(2-ethylhexoxy)-1,4-phenylenevinylene] blended with Au-capped TiO(2) nanocomposites are reported. Both the increased current in the active layer and low turn-on voltage were attributed to incorporation of Au-capped TiO(2) in the electroluminescent polymer. The maximal brightness of 11 630 cd/m(2) was observed in HPLED with a 1:1 ratio of Au-capped TiO(2). The enhanced performance was attributed to the roughness assisted charge transport induced by the Au-capped TiO(2) nanocomposites in the active polymer.open111

    Piperlongumine inhibits LMP1/MYC-dependent mouse B-lymphoma cells

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    AbstractPiperlongumine (PL), isolated from the fruit of Long pepper, Piper longum, is a cancer-inhibiting compound that selectively kills tumor cells while sparing their normal counterparts. Here we evaluated the efficacy with which PL suppresses malignant B cells derived from a newly developed, double-transgenic mouse model of human endemic Burkitt lymphoma (BL), designated mCD40-LMP1/iMycEฮผ. PL inhibited tumor cell proliferation in a concentration-dependent manner and induced apoptosis of neoplastic but not normal B cells. Treatment with PL resulted in downregulation of EBV-encoded LMP1, cellular Myc, constitutive NF-ฮบB activity, and a host of LMP1-Myc-NF-ฮบB-regulated target genes including Aurka, Bcat1, Bub1b, Ccnb1, Chek1, Fancd2, Tfrc and Xrcc6. Of note, p21Cip1-encoding Cdkn1a was suppressed independent of changes in Trp53 mRNA levels and p53 DNA-binding activity. Considering the central role of the LMP1โ€“NF-ฮบBโ€“Myc axis in B-lineage neoplasia, these findings further our understanding of the mechanisms by which PL inhibits B-lymphoma and provide a preclinical rationale for the inclusion of PL in new interventions in blood cancers

    Corrigendum: Behavioral and Neuroimaging Evidence for Facial Emotion Recognition in Elderly Korean Adults with Mild Cognitive Impairment, Alzheimer's Disease, and Frontotemporal Dementia

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    Background: Facial emotion recognition (FER) is impaired in individuals with frontotemporal dementia (FTD) and Alzheimerโ€™s disease (AD) when compared to healthy older adults. Since deficits in emotion recognition are closely related to caregiver burden or social interactions, researchers have fundamental interest in FER performance in patients with dementia.Purpose: The purpose of this study was to identify the performance profiles of six facial emotions (i.e., fear, anger, disgust, sadness, surprise, and happiness) and neutral faces measured among Korean healthy control (HCs), and those with mild cognitive impairment (MCI), AD, and FTD. Additionally, the neuroanatomical correlates of facial emotions were investigated.Methods: A total of 110 (33 HC, 32 MCI, 32 AD, 13 FTD) older adult participants were recruited from two different medical centers in metropolitan areas of South Korea. These individuals underwent an FER test that was used to assess the recognition of emotions or absence of emotion (neutral) in 35 facial stimuli. Repeated measures two-way analyses of variance were used to examine the distinct profiles of emotional recognition among the four groups. We also performed brain imaging and voxel-based morphometry (VBM) on the participants to examine the associations between FER scores and gray matter volume.Results: The mean score of negative emotion recognition (i.e., fear, anger, disgust, and sadness) clearly discriminated FTD participants from individuals with MCI and AD and HC [F(3,106) = 10.829, p 2 = 0.235], whereas the mean score of positive emotion recognition (i.e., surprise and happiness) did not. A VBM analysis showed negative emotions were correlated with gray matter volume of anterior temporal regions, whereas positive emotions were related to gray matter volume of fronto-parietal regions.Conclusion: Impairment of negative FER in patients with FTD is cross-cultural. The discrete neural correlates of FER indicate that emotional recognition processing is a multi-modal system in the brain. Focusing on the negative emotion recognition is a more effective way to discriminate healthy aging, MCI, and AD from FTD in older Korean adults.</p

    Chemokine Lkn-1/CCL15 enhances matrix metalloproteinase-9 release from human macrophages and macrophage-derived foam cells

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    Atherosclerosis is characterized by a chronic inflammatory disease, and chemokines play an important role in both initiation and progression of atherosclerosis development. Leukotactin-1 (Lkn-1/CCL15), a new member of the human CC chemokine family, is a potent chemoattractant for leukocytes. Our previous study has demonstrated that Lkn-1/CCL15 plays a role in the initiation of atherosclerosis, however, little is currently known whether Lkn-1/CCL15 is associated with the progression of atherosclerosis. Matrix metalloproteinases (MMPs) in human coronary atherosclerotic lesions play a crucial role in the progression of atherosclerosis by altering the vulnerability of plaque rupture. In the present study, we examined whether Lkn-1/CCL15 modulates MMP-9 release, which is a prevalent form expressed by activated macrophages and foam cells. Human THP-1 monocytic cells and/or human peripheral blood monocytes (PBMC) were treated with phorbol myristate acetate to induce their differentiation into macrophages. Foam cells were prepared by the treatment of THP-1 macrophages with human oxidized LDL. The macrophages and foam cells were treated with Lkn-1/CCL15, and the levels of MMP-9 release were measured by Gelatin Zymography. Lkn-1/CCL15 significantly enhanced the levels of MMP-9 protein secretion from THP-1 monocytic cells-derived macrophages, human PBMC-derived macrophages, as well as macrophage-derived foam cell in a dose dependent manner. Our data suggest that the action of Lkn-1/CCL15 on macrophages and foam cells to release MMP-9 may contribute to plaque destabilization in the progression of atherosclerosis

    Scutellaria baicalensis

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    Antimycin A (AMA) damages mitochondria by inhibiting mitochondrial electron transport and can produce reactive oxygen species (ROS). ROS formation, aging, and reduction of mitochondrial biogenesis contribute to mitochondrial dysfunction. The present study sought to investigate extracts of Scutellaria baicalensis and its flavonoids (baicalin, baicalein, and wogonin), whether they could protect mitochondria against oxidative damage. The viability of L6 cells treated with AMA increased in the presence of flavonoids and extracts of S. baicalensis. ATP production decreased in the AMA treated group, but increased by 50% in cells treated with flavonoids (except wogonin) and extracts of S. baicalensis compared to AMA-treated group. AMA treatment caused a significant reduction (depolarized) in mitochondrial membrane potential (MMP), whereas flavonoid treatment induced a significant increase in MMP. Mitochondrial superoxide levels increased in AMA treated cells, whereas its levels decreased when cells were treated with flavonoids or extracts of S. baicalensis. L6 cells treated with flavonoids and extracts of S. baicalensis increased their levels of protein expression compared with AMA-treated cells, especially water extracts performed the highest levels of protein expression. These results suggest that the S. baicalensis extracts and flavonoids protect against AMA-induced mitochondrial dysfunction by increasing ATP production, upregulating MMP, and enhancing mitochondrial function

    Novel PSEN1 G209A mutation in early-onset Alzheimer dementia supported by structural prediction

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Three main genes are described as causative genes for early-onset Alzheimer dementia (EOAD): APP, PSEN1 and PSEN2. We describe a woman with EOAD had a novel PSEN1 mutation. Case report A 54-year-old right-handed woman presented 12-year history of progressive memory decline. She was clinically diagnosed as familial Alzheimer's disease due to a PSEN1 mutation. One of two daughters also has the same mutation, G209A in the TM-IV of PS1 protein. Her mother had unspecified dementia that began at the age of 40s. PolyPhen2 and SIFT prediction suggested that G209A might be a damaging variant with high scores. 3D modeling revealed that G209A exchange could result significant changes in the PS1 protein. Conclusion We report a case of EOAD having probable novel PSEN1 (G209A) mutation verified with structural prediction

    Blood amyloid-ฮฒ oligomerization associated with neurodegeneration of Alzheimers disease

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    Introduction Oligomeric amyloid-รŸ is a major toxic species associated with Alzheimers disease pathogenesis. Methods used to measure oligomeric amyloid-ฮฒ in the blood have increased in number in recent years. The Multimer Detection System-Oligomeric Amyloid-ฮฒ (MDS-OAฮฒ) is a specific method to measure oligomerization tendencies in the blood. The objective of this study was to determine the association between amyloid-รŸ oligomerization in the plasma and structural changes of the brain. Methods We studied 162 subjects composed of 92 community-based normal healthy subjects, 17 with subjective cognitive decline, 14 with mild cognitive impairment and 39 with Alzheimers disease dementia. All subjects underwent MDS-OAฮฒ and three-dimensional T1 magnetic resonance imaging. To determine the structural changes of the brain that are statistically correlated with MDS-OAฮฒ level, we used voxel-based morphometry with corrections for age and total intracranial volume covariates. Results We found brain volume reduction in the bilateral temporal, amygdala, parahippocampal and lower parietal lobe and left cingulate and precuneus regions (family-wise error, pโ€‰<โ€‰0.05). Reduction was also found in white matter in proximity to the left temporal and bilateral lower parietal lobes and posterior corpus callosum (family-wise error, pโ€‰<โ€‰0.05). Brain volume increment was not observed in any regions within grey or white matter. Discussion Findings suggest that substantial correlation exists between amyloid รŸ oligomerization in the blood and brain volume reduction in the form of Alzheimers disease despite of uncertainty in the casual relationship.This work was supported by a grant of the Korea Healthcare Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (HI14C1251)

    Mutations at codons 178, 200-129, and 232 contributed to the inherited prion diseases in Korean patients

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    Background: Polymorphisms of the human prion protein gene (PRNP) contribute to the genetic determinants of Creutzfeldt-Jakob disease (CJD). Numerous polymorphisms in the promoter regions as well as the open reading frame of PRNP were investigated. Greater than 90% of Korean, Chinese, and Japanese carry the homozygote 129 MM codon. In Korea, polymorphisms have not been comprehensively studied, except codons 129 and 219 in PRNP among Korean CJD cases. Although polymorphisms at codons 129 and 219 play an important role in susceptibility to sporadic CJD, patients with other polymorphisms in PRNP exhibited critical distinctions of clinical symptoms. Methods: The genetic analyses of PRNP were carried out among probable CJD patients in comparison with the results from magnetic resonance imaging (MRI) and electroencephalogram (EEG). Results: The molecular analyses revealed that three mutations at codons D178N, E200K, and M232R in heterozygosity. Patients with the D178N and M232R mutations had a 129MM codon, whereas the patient with the E200K mutation showed 129MV heterozygosity. They all revealed strong 14-3-3 positive signals. The 67-year-old patient with the D178N-129M mutation showed progressive gait disturbance and dysarthria was in progress. The 58-year-old patient with the E200K mutation coupled to the 129MV codon had gait disturbance, dysarthria, agitation, and ataxic gait, and progressed rapidly to death 3 months from the first onset of symptoms. The 65-year-old patient with the M232R mutation showed rapidly progressive memory decline and gait disturbance, and died within 16 months after onset of symptoms. Conclusion: Despite differences in ethnicity, the clinical and pathological outcomes were similar to the respective mutations around the world, except absence of insomnia in D178N-129M subject.This research was funded by the Ministry for Health, Welfare and Family Affairs, Korea (grant number, 4800-4835-301-210).Shiga Y, 2007, J NEUROL, V254, P1509, DOI 10.1007/s00415-007-0540-9Kovacs GG, 2005, HUM GENET, V118, P166, DOI 10.1007/s00439-005-0020-1Zarranz JJ, 2005, J NEUROL NEUROSUR PS, V76, P1491, DOI 10.1136/jnnp.2005.056606KONG Q, 2004, PRION BIOL DIS, P673Spacey SD, 2004, ARCH NEUROL-CHICAGO, V61, P122Huang N, 2003, NEUROLOGY, V61, P354Kovacs GG, 2002, J NEUROL, V249, P1567, DOI 10.1007/s00415-002-0896-9Collinge J, 2001, ANNU REV NEUROSCI, V24, P519Schroter A, 2000, ARCH NEUROL-CHICAGO, V57, P1751Wong NKC, 2000, J MOL GRAPH MODEL, V18, P126Taniwaki Y, 2000, J NEUROL NEUROSUR PS, V68, P388Wiltfang J, 1999, J NEUROCHEM, V73, P2485Hainfellner JA, 1999, ANN NEUROL, V45, P812Swietnicki W, 1998, J BIOL CHEM, V273, P31048Riek R, 1998, P NATL ACAD SCI USA, V95, P11667, DOI 10.1073/pnas.95.20.11667Zerr I, 1998, ANN NEUROL, V43, P32ZEIDLER M, 1998, WHO MANUAL STRENGTHERosenmann H, 1997, NEUROLOGY, V49, P593Hoque MZ, 1996, ACTA NEUROPATHOL, V92, P441Nagayama M, 1996, NEUROLOGY, V47, P1313Steinhoff BJ, 1996, ARCH NEUROL-CHICAGO, V53, P162PARCHI P, 1995, CURR OPIN NEUROL, V8, P286BROWN P, 1994, ANN NEUROL, V35, P513PRUSINER SB, 1994, ANN NEUROL, V35, P385GABIZON R, 1994, PHILOS T ROY SOC B, V343, P385HITOSHI S, 1993, J NEUROL SCI, V120, P208GOLDFARB LG, 1992, SCIENCE, V258, P806BROWN P, 1991, EUR J EPIDEMIOL, V7, P469STAHL N, 1990, BIOCHEMISTRY-US, V29, P8879BROWN P, 1986, ANN NEUROL, V20, P597
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