849 research outputs found
Mitigating Alzheimer’s disease with natural polyphenols: a review
According to Alzheimer’s Disease International (ADI), nearly 50 million people worldwide were living with dementia in 2017, and this number is expected to triple by 2050. Despite years of research in this field, the root cause and mechanisms responsible for Alzheimer’s disease (AD) have not been fully elucidated yet. Moreover, promising preclinical results have repeatedly failed to translate into patient treatments. Until now, none of the molecules targeting AD has successfully passed the Phase III trial. Although natural molecules have been extensively studied, they normally require high concentrations to be effective; alternately, they are too large to cross the blood-brain barrier (BBB). In this review, we report on AD treatment strategies, with a virtually exclusive focus on green chemistry (natural phenolic molecules). These include therapeutic strategies for decreasing amyloid- β (Aβ) production, preventing and/or altering A β aggregation, and reducing oligomers cytotoxicity such as curcumin, (-)- epigallocatechin-3-gallate (EGCG), morin, resveratrol, tannic acid, and other natural green molecules. We also examinewhether consideration should be given to potential candidates used outside of medicine and nutrition, through a discussion of two intermediate-sized green molecules, with very similar molecular structures and key properties, which exhibit potential in mitigating Alzheimer’s disease
Relationship patterns of the female juvenile delinquent : an exploration of the factors involved in the relationship patterns of juvenile delinquents before and after institutionalization
iv, 35 leaves ; 28 cm.Bibliography: leaf 35.Online version unavailable; print version available from Patrick Power Library.This study looks at the relationship patterns of female juvenile delinquents before and after institutionalization and at some factors that might have brought about changes in these patterns.
Nine girls forming the senior group at the Nova Scotia Home for Girls in Truro, Nova Scotia, were interviewed in December 1968. The information gathered by a semi-instructed interview was explored and the major trends were described by tables.
These findings suggest that the relationship patterns of the girls were quite poor before institutionalization but that those patterns had improved since they had been at the Home for Girls. A suggested reason for this was the existence of more understanding and kindness on the part of the staff of the institution. It was recommended that all personnel in rehabilitation units should be understanding and be able to express it, and that social workers should attempt to explain the importance of understanding and kindness to the girl’s parents
Stripes in cuprate superconductors: Excitations and dynamic dichotomy
We present a short account of the present experimental situation of stripes
in cuprates followed by a review of our present understanding of their ground
state and excited state properties. Collective modes, the dynamical structure
factor, and the optical conductivity of stripes are computed using the
time-dependent Gutzwiller approximation applied to realistic one band and three
band Hubbard models, and are found to be in excellent agreement with
experiment. On the other hand, experiments like angle-resolved photoemission
and scanning tunneling microscopy show the coexistence of stripes at high
energies with Fermi liquid quasiparticles at low energies. We show that a
phenomenological model going beyond mean-field can reconcile this dynamic
dichotomy.Comment: 20 pages, 14 figures. Review paper for a Special Issue of Physica C
on "Stripes and Electronic Liquid Crystals in Strongly Correlated Systems
A Small but Efficient Collaboration for the Spiral2 Control System Development
http://accelconf.web.cern.ch/AccelConf/ICALEPCS2013/papers/tucobab01.pdfThe Spiral2 radioactive ion beam facility to be commissioned in 2014 at Ganil (Caen) is built within international collaborations. This also concerns the control system development shared by three laboratories: Ganil has to coordinate the control and automated systems work packages, CEA/IRFU is in charge of the "injector" (sources and low energy beam lines) and the LLRF, CNRS/IPHC provides the emittancemeters and a beam diagnostics platform. Besides the technology Epics based, this collaboration, although being handled with a few people, nevertheless requires an appropriate and tight organization to reach the objectives given by the project. This contribution describes how, started in 2006, the collaboration for controls has been managed both from the technological point of view and the organizational one, taking into account not only the previous experience, technical background or skill of each partner, but also their existing working practices and "cultural" approaches. A first feedback comes from successful beam tests carried out at Saclay and Grenoble; a next challenge is the migration to operation, Ganil having to run Spiral2 as the other members are moving to new projects
Polyphenol-peptide interactions in mitigation of Alzheimer’s disease : role of biosurface-induced aggregation
Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder,
responsible for nearly two-thirds of all dementia cases. In this review, we report the potential AD
treatment strategies focusing on natural polyphenol molecules (green chemistry) and more specifically
on the inhibition of polyphenol-induced amyloid aggregation/disaggregation pathways: in bulk and on
biosurfaces. We discuss how these pathways can potentially alter the structure at the early stages of AD,
hence delaying the aggregation of Aβ and tau. We also discuss multidisciplinary approaches, combining
experimental and modelling methods, that can better characterize the biochemical and biophysical
interactions between proteins and phenolic ligands. In addition to the surface-induced aggregation,
which can occur on surfaces where protein can interact with other proteins and polyphenols, we
suggest a new concept referred as “confinement stability”. Here. on the contrary, the adsorption
of Aβ and tau on biosurfaces other than Aβ- and tau-fibrils, e.g. red blood cells (RBCs), can lead
to confinement stability that minimizes the aggregation of Aβ and tau. Overall, these mechanisms
may participate directly or indirectly in mitigating neurodegenerative diseases, by preventing protein
self-association, slowing down the aggregation processes, and delaying the progression of AD
Variational quantum Monte Carlo study of two-dimensional Wigner crystals: exchange, correlation, and magnetic field effects
The two-dimensional Wigner crystals are studied with the variational quantum
Monte Carlo method. The close relationship between the ground-state
wavefunction and the collective excitations in the system is illustrated, and
used to guide the construction of the ground-state wavefunction of the strongly
correlated solid. Exchange, correlation, and magnetic field effects all give
rise to distinct physical phenomena. In the absence of any external magnetic
field, interesting spin-orderings are observed in the ground-state of the
electron crystal in various two-dimensional lattices. In particular,
two-dimensional bipartite lattices are shown not to lead necessarily to an
antiferromagnetic ground-state. In the quantum Hall effect regime, a strong
magnetic field introduces new energy and length scales. The magnetic field
quenches the kinetic energy and poses constraints on how the electrons may
correlate with each other. Care is taken to ensure the appropriate
translational properties of the wavefunction when the system is in a uniform
magnetic field. We have examined the exchange, intra-Landau-level correlation
as well as Landau-level-mixing effects with various variational wavefunctions.
We also determine their dependences on the experimental parameters such as the
carrier effective mass at a modulation-doped semiconductor heterojunction. Our
results, when combined with some recent calculations for the energy of the
fractional quantum Hall liquid including Landau-level-mixing, show
quantitatively that in going from -doping to -doping in
heterojunction systems, the crossover filling factor from the fractional
quantum Hall liquid to the Wigner crystal changes from filling factor to . This lends strong support to the claim that theComment: LaTex file, 14 figures available from [email protected]
Ecological impacts of non-native Pacific oysters (Crassostrea gigas) and management measures for protected areas in Europe
Pacific oysters are now one of the most ‘globalised’ marine invertebrates. They dominate bivalve aquaculture production in many regions and wild populations are increasingly becoming established, with potential to displace native species and modify habitats and ecosystems. While some fishing communities may benefit from wild populations, there is now a tension between the continued production of Pacific oysters and risk to biodiversity, which is of particular concern within protected sites. The issue of the Pacific oyster therefore locates at the intersection between two policy areas: one concerning the conservation of protected habitats, the other relating to livelihoods and the socio-economics of coastal aquaculture and fishing communities. To help provide an informed basis for management decisions, we first summarise evidence for ecological impacts of wild Pacific oysters in representative coastal habitats. At local scales, it is clear that establishment of Pacific oysters can significantly alter diversity, community structure and ecosystem processes, with effects varying among habitats and locations and with the density of oysters. Less evidence is available to evaluate regional-scale impacts. A range of management measures have been applied to mitigate negative impacts of wild Pacific oysters and we develop recommendations which are consistent with the scientific evidence and believe compatible with multiple interests. We conclude that all stakeholders must engage in regional decision making to help minimise negative environmental impacts, and promote sustainable industry development
Molecular interactions of tannic acid with proteins associated with SARS-CoV-2 infectivity
The overall impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on our society is unprecedented. The identification of small natural ligands that could prevent the entry and/or replication of the coronavirus remains a pertinent approach to fight the coronavirus disease (COVID-19) pandemic. Previously, we showed that the phenolic compounds corilagin and 1,3,6-tri-O-galloyl-β-D-glucose (TGG) inhibit the interaction between the SARS-CoV-2 spike protein receptor binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 target receptor on the cell membrane of the host organism. Building on these promising results, we now assess the effects of these phenolic ligands on two other crucial targets involved in SARS-CoV-2 cell entry and replication, respectively: transmembrane protease serine 2 (TMPRSS2) and 3-chymotrypsin like protease (3CLpro) inhibitors. Since corilagin, TGG, and tannic acid (TA) share many physicochemical and structural properties, we investigate the binding of TA to these targets. In this work, a combination of experimental methods (biochemical inhibition assays, surface plasmon resonance, and quartz crystal microbalance with dissipation monitoring) confirms the potential role of TA in the prevention of SARS-CoV-2 infectivity through the inhibition of extracellular RBD/ACE2 interactions and TMPRSS2 and 3CLpro activity. Moreover, molecular docking prediction followed by dynamic simulation and molecular mechanics Poisson–Boltzmann surface area (MMPBSA) free energy calculation also shows that TA binds to RBD, TMPRSS2, and 3CLpro with higher affinities than TGG and corilagin. Overall, these results suggest that naturally occurring TA is a promising candidate to prevent and inhibit the infectivity of SARS-CoV-2
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