403 research outputs found
A bayesian meta-analysis of multiple treatment comparisons of systemic regimens for advanced pancreatic cancer
© 2014 Chan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: For advanced pancreatic cancer, many regimens have been compared with gemcitabine (G) as the standard arm in randomized controlled trials. Few regimens have been directly compared with each other in randomized controlled trials and the relative efficacy and safety among them remains unclear
Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe/MoSe bilayers
Structural engineering of van der Waals heterostructures via stacking and
twisting has recently been used to create moir\'e superlattices, enabling the
realization of new optical and electronic properties in solid-state systems. In
particular, moir\'e lattices in twisted bilayers of transition metal
dichalcogenides (TMDs) have been shown to lead to exciton trapping, host Mott
insulating and superconducting states, and act as unique Hubbard systems whose
correlated electronic states can be detected and manipulated optically.
Structurally, these twisted heterostructures also feature atomic reconstruction
and domain formation. Unfortunately, due to the nanoscale sizes (~10 nm) of
typical moir\'e domains, the effects of atomic reconstruction on the electronic
and excitonic properties of these heterostructures could not be investigated
systematically and have often been ignored. Here, we use near-0 twist angle
MoSe/MoSe bilayers with large rhombohedral AB/BA domains to directly
probe excitonic properties of individual domains with far-field optics. We show
that this system features broken mirror/inversion symmetry, with the AB and BA
domains supporting interlayer excitons with out-of-plane (z) electric dipole
moments in opposite directions. The dipole orientation of ground-state
-K interlayer excitons (X) can be flipped with electric fields,
while higher-energy K-K interlayer excitons (X) undergo
field-asymmetric hybridization with intralayer K-K excitons (X). Our study
reveals the profound impacts of crystal symmetry on TMD excitons and points to
new avenues for realizing topologically nontrivial systems, exotic
metasurfaces, collective excitonic phases, and quantum emitter arrays via
domain-pattern engineering.Comment: 29 pages, 4 figures in main text, 6 figures in supplementary
informatio
Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSeâ‚‚/MoSeâ‚‚ bilayers
Van der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices, enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping, host Mott insulating and superconducting states6 and act as unique Hubbard systems whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation. However, due to the nanoscale size of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties have not been systematically investigated. Here we use near-0°-twist-angle MoSe₂/MoSe₂ bilayers with large rhombohedral AB/BA domains to directly probe the excitonic properties of individual domains with far-field optics. We show that this system features broken mirror/inversion symmetry, with the AB and BA domains supporting interlayer excitons with out-of-plane electric dipole moments in opposite directions. The dipole orientation of ground-state Γ–K interlayer excitons can be flipped with electric fields, while higher-energy K–K interlayer excitons undergo field-asymmetric hybridization with intralayer K–K excitons. Our study reveals the impact of crystal symmetry on TMD excitons and points to new avenues for realizing topologically non-trivial systems, exotic metasurfaces, collective excitonic phases and quantum emitter arrays via domain-pattern engineering
Aldo-keto reductases are biomarkers of NRF2 activity and are co-ordinately overexpressed in non-small cell lung cancer
BACKGROUND: Although the nuclear factor-erythroid 2-related factor 2 (NRF2) pathway is one of the most frequently dysregulated in cancer, it is not clear whether mutational status is a good predictor of NRF2 activity. Here we utilise four members of the aldo-keto reductase (AKR) superfamily as biomarkers to address this question. METHODS: Twenty-three cell lines of diverse origin and NRF2-pathway mutational status were used to determine the relationship between AKR expression and NRF2 activity. AKR expression was evaluated in lung cancer biopsies and Cancer Genome Atlas (TCGA) and Oncomine data sets. RESULTS: AKRs were expressed at a high basal level in cell lines carrying mutations in the NRF2 pathway. In non-mutant cell lines, co-ordinate induction of AKRs was consistently observed following activation of NRF2. Immunohistochemical analysis of lung tumour biopsies and interrogation of TCGA data revealed that AKRs are enriched in both squamous cell carcinomas (SCCs) and adenocarcinomas that contain somatic alterations in the NRF2 pathway but, in the case of SCC, AKRs were also enriched in most other tumours. CONCLUSIONS: An AKR biomarker panel can be used to determine NRF2 status in tumours. Hyperactivation of the NRF2 pathway is far more prevalent in lung SCC than previously predicted by genomic analyses
World-Wide FINGERS Network: A global approach to risk reduction and prevention of dementia
© 2020 The Authors. Alzheimer\u27s & Dementia published by Wiley Periodicals, Inc. on behalf of Alzheimer\u27s Association Reducing the risk of dementia can halt the worldwide increase of affected people. The multifactorial and heterogeneous nature of late-onset dementia, including Alzheimer\u27s disease (AD), indicates a potential impact of multidomain lifestyle interventions on risk reduction. The positive results of the landmark multidomain Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) support such an approach. The World-Wide FINGERS (WW-FINGERS), launched in 2017 and including over 25 countries, is the first global network of multidomain lifestyle intervention trials for dementia risk reduction and prevention. WW-FINGERS aims to adapt, test, and optimize the FINGER model to reduce risk across the spectrum of cognitive decline—from at-risk asymptomatic states to early symptomatic stages—in different geographical, cultural, and economic settings. WW-FINGERS aims to harmonize and adapt multidomain interventions across various countries and settings, to facilitate data sharing and analysis across studies, and to promote international joint initiatives to identify globally implementable and effective preventive strategies
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The integration of lipid-sensing and anti-inflammatory effects: how the PPARs play a role in metabolic balance
The peroxisomal proliferating-activated receptors (PPARs) are lipid-sensing transcription factors that have a role in embryonic development, but are primarily known for modulating energy metabolism, lipid storage, and transport, as well as inflammation and wound healing. Currently, there is no consensus as to the overall combined function of PPARs and why they evolved. We hypothesize that the PPARs had to evolve to integrate lipid storage and burning with the ability to reduce oxidative stress, as energy storage is essential for survival and resistance to injury/infection, but the latter increases oxidative stress and may reduce median survival (functional longevity). In a sense, PPARs may be an evolutionary solution to something we call the 'hypoxia-lipid' conundrum, where the ability to store and burn fat is essential for survival, but is a 'double-edged sword', as fats are potentially highly toxic. Ways in which PPARs may reduce oxidative stress involve modulation of mitochondrial uncoupling protein (UCP) expression (thus reducing reactive oxygen species, ROS), optimising forkhead box class O factor (FOXO) activity (by improving whole body insulin sensitivity) and suppressing NFkB (at the transcriptional level). In light of this, we therefore postulate that inflammation-induced PPAR downregulation engenders many of the signs and symptoms of the metabolic syndrome, which shares many features with the acute phase response (APR) and is the opposite of the phenotype associated with calorie restriction and high FOXO activity. In genetically susceptible individuals (displaying the naturally mildly insulin resistant 'thrifty genotype'), suboptimal PPAR activity may follow an exaggerated but natural adipose tissue-related inflammatory signal induced by excessive calories and reduced physical activity, which normally couples energy storage with the ability to mount an immune response. This is further worsened when pancreatic decompensation occurs, resulting in gluco-oxidative stress and lipotoxicity, increased inflammatory insulin resistance and oxidative stress. Reactivating PPARs may restore a metabolic balance and help to adapt the phenotype to a modern lifestyle
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