296 research outputs found
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The interplay between thermodynamics and kinetics in the solid-state synthesis of layered oxides.
In the synthesis of inorganic materials, reactions often yield non-equilibrium kinetic byproducts instead of the thermodynamic equilibrium phase. Understanding the competition between thermodynamics and kinetics is a fundamental step towards the rational synthesis of target materials. Here, we use in situ synchrotron X-ray diffraction to investigate the multistage crystallization pathways of the important two-layer (P2) sodium oxides Na0.67MO2 (M = Co, Mn). We observe a series of fast non-equilibrium phase transformations through metastable three-layer O3, O3' and P3 phases before formation of the equilibrium two-layer P2 polymorph. We present a theoretical framework to rationalize the observed phase progression, demonstrating that even though P2 is the equilibrium phase, compositionally unconstrained reactions between powder precursors favour the formation of non-equilibrium three-layered intermediates. These insights can guide the choice of precursors and parameters employed in the solid-state synthesis of ceramic materials, and constitutes a step forward in unravelling the complex interplay between thermodynamics and kinetics during materials synthesis
Gastrodin ameliorates synaptic impairment, mitochondrial dysfunction and oxidative stress in N2a/APP cells
Alzheimer's disease is characterized by abnormal β-amyloid and tau accumulation, mitochondrial dysfunction, oxidative stress, and synaptic dysfunction. Here, we aimed to assess the mechanisms and signalling pathways in the neuroprotective effect of gastrodin, a phenolic glycoside, on murine neuroblastoma N2a cells expressing human Swedish mutant APP (N2a/APP). We found that gastrodin increased the levels of presynaptic-SNAP, synaptophysin, and postsynaptic-PSD95 and reduced phospho-tau Ser396, APP and Aβ1-42 levels in N2a/APP cells. Gastrodin treatment reduced reactive oxygen species generation, lipid peroxidation, mitochondrial fragmentation and DNA oxidation; restored mitochondrial membrane potential and intracellular ATP production. Upregulated phospho-GSK-3β and reduced phospho-ERK and phospho-JNK were involved in the protective effect of gastrodin. In conclusion, we demonstrated the neuroprotective effect of gastrodin in the N2a/APP cell line by ameliorating the impairment on synaptic and mitochondrial function, reducing tau phosphorylation, Aβ1-42 levels as well as reactive oxygen species generation. These results provide new mechanistic insights into the potential effect of gastrodin in the treatment of Alzheimer’s disease
Comprehensive Bibliometric Analysis of the Kynurenine Pathway in Mood Disorders: Focus on Gut Microbiota Research
Background: Emerging evidence implicates the dysregulated kynurenine pathway (KP), an immune-inflammatory pathway, in the pathophysiology of mood disorders (MD), including depression and bipolar disorder characterized by a low-grade chronic pro-inflammatory state. The metabolites of the KP, an important part of the microbiota-gut-brain axis, serve as immune system modulators linking the gut microbiota (GM) with the host central nervous system.Aim: This bibliometric analysis aimed to provide a first glimpse into the KP in MD, with a focus on GM research in this field, to guide future research and promote the development of this field.Methods: Publications relating to the KP in MD between the years 2000 and 2020 were retrieved from the Scopus and Web of Science Core Collection (WoSCC), and analyzed in CiteSpace (5.7 R5W), biblioshiny (using R-Studio), and VOSviewer (1.6.16).Results: In total, 1,064 and 948 documents were extracted from the Scopus and WoSCC databases, respectively. The publications have shown rapid growth since 2006, partly owing to the largest research hotspot appearing since then, “quinolinic acid.” All the top five most relevant journals were in the neuropsychiatry field, such as Brain Behavior and Immunity. The United States and Innsbruck Medical University were the most influential country and institute, respectively. Journal co-citation analysis showed a strong tendency toward co-citation of research in the psychiatry field. Reference co-citation analysis revealed that the top four most important research focuses were “kynurenine pathway,” “psychoneuroimmunology,” “indoleamine 2,3-dioxygenase,” and “proinflammatory cytokines,” and the most recent focus was “gut-brain axis,” thus indicating the role of the KP in bridging the GM and the host immune system, and together reflecting the field’s research foundations. Overlap analysis between the thematic map of keywords and the keyword burst analysis revealed that the topics “Alzheimer’s disease,” “prefrontal cortex,” and “acid,” were research frontiers.Conclusion: This comprehensive bibliometric study provides an updated perspective on research associated with the KP in MD, with a focus on the current status of GM research in this field. This perspective may benefit researchers in choosing suitable journals and collaborators, and aid in the further understanding of the field’s hotspots and frontiers, thus facilitating future research
Study of in decay
Using a sample of decays collected with
the BESIII detector, partial wave analyses of the decay are performed within the invariant mass region below 1.6 . The
covariant tensor amplitude method is used in both mass independent and mass
dependent approaches. Both analysis approaches exhibit dominant pseudoscalar
and axial vector components, and show good consistency for the other individual
components. Furthermore, the mass dependent analysis reveals that the
invariant mass spectrum for the pseudoscalar
component can be well described with two isoscalar resonant states, , the with a mass of
and a width of ,
and the with a mass of
and a width of .
The first and second uncertainties are statistical and systematic,
respectively. Alternate models for the pseudoscalar component are also tested,
but the description of the invariant mass spectrum
deteriorates significantly.Comment: 20 pages, 6 figures, 6 table
Amplitude analysis and branching fraction measurement of the decay \boldmath
The singly Cabibbo-suppressed decay
is observed, using a data set corresponding to an integrated luminosity of 6.32
recorded by the BESIII detector at the centre-of-mass energies
between 4.178 and 4.226 GeV. The first amplitude analysis of reveals the sub-structures in this decay and
determines the fractions and relative phases of different intermediate
processes. The dominant intermediate process is , with
a fit fraction of . With the
detection efficiency based on our amplitude analysis, the absolute branching
fraction for is measured to be
Observation of the and evidence for a new vector charmonium-like state in
Cross sections for the process
at center-of-mass energies from to GeV are measured using data
samples with a total integrated luminosity of 21.2 fb collected by the
BESIII detector operating at the BEPCII storage ring. The state is
observed in the energy dependence of the cross section for the first time with a statistical significance of
26.0. In addition, an enhancement around GeV, called the
, is seen with a statistical significance of 4.2. There is no
clear structure around GeV. Using a fit with a coherent sum of three
Breit-Wigner functions, we determine the mass and width of the state
to be MeV/ and MeV,
respectively, and the mass and width of the state to be MeV/ and MeV, respectively,
where the first uncertainties are statistical and the second are systematic. In
addition, the average Born cross section ratio of to is measured to be
, or if
three-body phase space is considered.Comment: Update draft based the comments from PRD refere
Search for hidden-charm tetraquark with strangeness in
We report a search for a heavier partner of the recently observed
state, denoted as , in the process , based on collision data
collected at the center-of-mass energies of , 4.682 and 4.699
GeV with the BESIII detector. The is of interest as it is
expected to be a candidate for a hidden-charm and open-strange tetraquark. A
partial-reconstruction technique is used to isolate recoil-mass spectra,
which are probed for a potential contribution from (). We find an excess of () candidates with a significance of , after
considering systematic uncertainties, at a mass of . As the data
set is limited in size, the upper limits are evaluated at the 90% confidence
level on the product of the Born cross section and the branching fraction of
, at the three energy points, under different assumptions
of the mass from 4.120 to 4.140 MeV and of the width from
10 to 50 MeV. Under various mass and width assumptions, the upper limits of
are found to lie in the range of ,
and pb at , 4.682 and 4.699 GeV,
respectively. The larger data samples that will be collected in the coming
years will allow a clearer picture to emerge concerning the existence and
nature of the state.Comment: 17 pages, 7 figure
Precise Measurements of Decay Parameters and Asymmetry with Entangled Pairs
Based on 10 billion events collected at the BESIII experiment, a
search for violation in decay is performed in the difference
between -odd decay parameters for
and for by using the
process . With a
five-dimensional fit to the full angular distributions of the daughter baryon,
the most precise values for the decay parameters are determined to be
and , respectively. The and averaged
value of the decay parameter is extracted to be with unprecedented accuracy. The asymmetry
is determined to be
, which is one of the most precise measurements
in the baryon sector. The reported results for the decay parameter will play an
important role in the studies of the polarizations and violations for the
strange, charmed and beauty baryons
Observation of
By analyzing events collected with the
BESIII detector operating at the BEPCII collider, the decays of (, 1 and 2) are observed for the first time with
statistical significances of , , and ,
respectively. The product branching fractions of
and are measured. Dividing by the world
averages of the branching fractions of , the
branching fractions of decays are
determined to be ,
, and
for , 1 and 2, respectively, where the first uncertainties are statistical
and the second systematic.Comment: 9 pages, 4 figure
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