scholarly journals Definitive evidence of interlayer coupling betweenGa1−xMnxAslayers separated by a nonmagnetic spacer

2007 ◽  
Vol 76 (20) ◽  
Author(s):  
B. J. Kirby ◽  
J. A. Borchers ◽  
X. Liu ◽  
Z. Ge ◽  
Y. J. Cho ◽  
...  
Keyword(s):  
Interlayer Coupling ◽  
Definitive Evidence ◽  
Nonmagnetic Spacer

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

Is it All Said for NSAIDs in Alzheimer’s Disease? Role of Mitochondrial Calcium Uptake

2018 ◽  
Vol 15 (6) ◽  
pp. 504-510 ◽  
Author(s):  
Sara Sanz-Blasco ◽  
Maria Calvo-Rodríguez ◽  
Erica Caballero ◽  
Monica Garcia-Durillo ◽  
Lucia Nunez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Death ◽  
Amyloid Β ◽  
Epidemiological Data ◽  
Amyloid Β Peptide ◽  
Aβ Oligomers ◽  
Mitochondrial Potential ◽  
Disease Modifying Drugs ◽  
Definitive Evidence

Objectives: Epidemiological data suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may protect against Alzheimer's disease (AD). Unfortunately, recent trials have failed in providing compelling evidence of neuroprotection. Discussion as to why NSAIDs effectivity is uncertain is ongoing. Possible explanations include the view that NSAIDs and other possible disease-modifying drugs should be provided before the patients develop symptoms of AD or cognitive decline. In addition, NSAID targets for neuroprotection are unclear. Both COX-dependent and independent mechanisms have been proposed, including γ-secretase that cleaves the amyloid precursor protein (APP) and yields amyloid β peptide (Aβ). Methods: We have proposed a neuroprotection mechanism for NSAIDs based on inhibition of mitochondrial Ca2+ overload. Aβ oligomers promote Ca2+ influx and mitochondrial Ca2+ overload leading to neuron cell death. Several non-specific NSAIDs including ibuprofen, sulindac, indomethacin and Rflurbiprofen depolarize mitochondria in the low µM range and prevent mitochondrial Ca2+ overload induced by Aβ oligomers and/or N-methyl-D-aspartate (NMDA). However, at larger concentrations, NSAIDs may collapse mitochondrial potential (ΔΨ) leading to cell death. Results: Accordingly, this mechanism may explain neuroprotection at low concentrations and damage at larger doses, thus providing clues on the failure of promising trials. Perhaps lower NSAID concentrations and/or alternative compounds with larger dynamic ranges should be considered for future trials to provide definitive evidence of neuroprotection against AD.

Delineating Lake Types of the Jurassic East Berlin Formation, Hartford Basin, Newark Supergroup

2016 ◽  
Author(s):  
Alexander A. Conti ◽  
◽  
Elizabeth H. Gierlowski-Kordesch
Keyword(s):  
New England ◽  
Tholeiitic Basalt ◽  
Geochemical Evolution ◽  
Lake Basin ◽  
East Berlin ◽  
Definitive Evidence ◽  
Lacustrine Facies ◽  
Lake Deposits ◽  
First Time ◽  
Biomarker Data

The Mesozoic Hartford Basin, a fault-bounded half-graben in New England, is composed of four sedimentologic units displaying lacustrine, playa, and alluvial conditions separated by three tholeiitic basalt flows. Limited outcrop, however, has restricted analyses across the basin. The Jurassic East Berlin Formation, in particular, crops out only in the southern and northern extents of the basin, exposing the upper 100-118-m of deposits. As a result, a new core analysis across a 600-m-transect of East Berlin rocks has been completed in the central region of the basin, exposing the entire 195-m thickness of the formation for the first time. Cores expose eight 3-m-thick lacustrine mudrock units, the upper six of which are correlative to lake deposits identified in the southern and northern extents of the basin. Additionally, thin chicken-wire evaporites demarcate the lowermost, previously unexposed, lacustrine unit, 7-m beneath a 15-cm-thick tufa horizon. Thin playa deposits and thick sheetflood and Vertisol packages separate these lake sequences over 5-30-m of vertical distance.To supplement these sedimentologic data, and better understand lake geochemistry of the basin during East Berlin time, new biomarker analyses have been applied to each of the eight lacustrine mudrock units for the first time. Biomarker data are useful for determining the lake-basin type, a paleolake classification system derived by Bohacs, Carroll, and others to describe predictable physical and geochemical evolution within rift basins from fluvial facies to over-filled, balance-filled, and under-filled lacustrine facies; subsequently, balance-filled lacustrine facies grade to a terminal fluvial facies during changes in accommodation space through time. While fluvial facies envelope lake deposits within the Hartford Basin, identifying the lake types within the East Berlin has been problematic because of limited exposures. These new sedimentologic and biomarker analyses, however, suggest balance-filled lacustrine conditions at the base of the East Berlin that grade into under-filled conditions upsection. These new biomarker data finally provide definitive evidence for changing lake types during East Berlin time.

Lost Glory

2018 ◽  
Author(s):  
Sumit K. Majumdar
Keyword(s):  
Positive Impact ◽  
Positive Outcomes ◽  
State Sector ◽  
Definitive Evidence ◽  
Industrial Landscape ◽  
Intellectual Origins ◽  
Automobile Manufacturer ◽  
High Output

Lost Glory: India’s Capitalism Story describes India’s industrialization experiences. Questions about long-term industry and productivity evolution, and their impact on economic growth, lie at the heart of discourses of capitalism. The book is based on detailed empirical analyses of India’s industrialization over a period of almost seven decades, and a case study of Maruti Suzuki, India’s largest automobile manufacturer. The deeply nuanced depiction of the historical political economy that has affected India’s industrialization is a unique feature. This history will enlighten everyone interested in India. The presentation takes readers on a definitive evidence-based survey of India’s industrial landscape. It includes a detailed historical description of the intellectual origins of India’s modern industrialization, anchored in a privileged view of economic policymaking. Grounded in historical and political analyses, the facts derived on India’s long-term economic performance are used to set the record straight. It is unsparing in its assessments where the evidence warrants such conclusions. Its findings will transform debate, and set the agenda for thoughtfully assessing the future course of India’s prosperity. The author overturns the assumptions that India’s much-vaunted private sector firms only engender positive outcomes, finding State-sector firms to have become efficient, and the molecular sector to be as effective overall, while also challenging the notion that privatization is necessary for progress. Conversely, it is found that competition policy innovations to have had positive impact. Practical suggestions are provided and three fundamental reforms, one administrative, one structural, and one behavioral, necessary to regenerate high output, are advocated.

scholarly journals Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Interlayer Coupling ◽  
First Principles Calculation ◽  
Optimization Approach ◽  
Binding Model ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
Topological Quantum ◽  
First Time

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

scholarly journals Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1994
Author(s):  
Han Li ◽  
Yating Ma ◽  
Zhongjie Xu ◽  
Xiang’ai Cheng ◽  
Tian Jiang
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Interlayer Coupling ◽  
Carrier Dynamics ◽  
Probe Signal ◽  
Exciton Resonance ◽  
Pump Probe ◽  
Metal Dichalcogenides ◽  
Photoluminescence Enhancement ◽  
Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

Sign in / Sign up

Export Citation Format

Share Document