3,996 research outputs found
The spherical nanoparticle-encapsulated chlorhexidine enhances anti-biofilm efficiency through an effective releasing mode and close microbial interactions
published_or_final_versio
Nanoparticle-encapsulated chlorhexidine against oral bacterial biofilms
Background: Chlorhexidine (CHX) is a widely used antimicrobial agent in dentistry. Herein, we report the synthesis of a novel mesoporous silica nanoparticle-encapsulated pure CHX (Nano-CHX), and its mechanical profile and antimicrobial properties against oral biofilms.
Methodology/Principal Findings: The release of CHX from the Nano-CHX was characterized by UV/visible absorption spectroscopy. The antimicrobial properties of Nano-CHX were evaluated in both planktonic and biofilm modes of representative oral pathogenic bacteria. The Nano-CHX demonstrated potent antibacterial effects on planktonic bacteria and mono-species biofilms at the concentrations of 50-200 mu g/mL against Streptococcus mutans, Streptococcus sobrinus, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Enterococccus faecalis. Moreover, Nano-CHX effectively suppressed multi-species biofilms such as S. mutans, F. nucleatum, A. actinomycetemcomitans and Porphyromonas gingivalis up to 72 h.
Conclusions/Significance: This pioneering study demonstrates the potent antibacterial effects of the Nano-CHX on oral biofilms, and it may be developed as a novel and promising anti-biofilm agent for clinical use.published_or_final_versio
A novel COâ-responsive systemic signaling pathway controlling plant mycorrhizal symbiosis
Elevated atmospheric carbon dioxide (eCOâ) concentrations promote symbiosis between roots and arbuscular mycorrhizal fungi (AMF), modifying plant nutrient acquisition and cycling of carbon, nitrogen and phosphate. However, the biological mechanisms by which plants transmit aerial eCOâ cues to roots, to alter the symbiotic associations remain unknown.
We used a range of interdisciplinary approaches, including gene silencing, grafting, transmission electron microscopy, liquid chromatography tandem mass spectrometry (LCâMS/MS), biochemical methodologies and gene transcript analysis to explore the complexities of environmental signal transmission from the point of perception in the leaves at the apex to the roots.
Here we show that eCOâ triggers apoplastic hydrogen peroxide (HâOâ)âdependent auxin production in tomato shoots followed by systemic signaling that results in strigolactone biosynthesis in the roots. This redoxâauxinâstrigolactone systemic signaling cascade facilitates eCOââinduced AMF symbiosis and phosphate utilization.
Our results challenge the current paradigm of eCOâ effects on AMF and provide new insights into potential targets for manipulation of AMF symbiosis for high nutrient utilization under future climate change scenarios
Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach
Operator entanglement of two-qubit joint unitary operations is revisited.
Schmidt number is an important attribute of a two-qubit unitary operation, and
may have connection with the entanglement measure of the unitary operator. We
found the entanglement measure of two-qubit unitary operators is classified by
the Schmidt number of the unitary operators. The exact relation between the
operator entanglement and the parameters of the unitary operator is clarified
too.Comment: To appear in the Brazilian Journal of Physic
Quantum and classical criticality in a dimerized quantum antiferromagnet
A quantum critical point (QCP) is a singularity in the phase diagram arising
due to quantum mechanical fluctuations. The exotic properties of some of the
most enigmatic physical systems, including unconventional metals and
superconductors, quantum magnets, and ultracold atomic condensates, have been
related to the importance of the critical quantum and thermal fluctuations near
such a point. However, direct and continuous control of these fluctuations has
been difficult to realize, and complete thermodynamic and spectroscopic
information is required to disentangle the effects of quantum and classical
physics around a QCP. Here we achieve this control in a high-pressure,
high-resolution neutron scattering experiment on the quantum dimer material
TlCuCl3. By measuring the magnetic excitation spectrum across the entire
quantum critical phase diagram, we illustrate the similarities between quantum
and thermal melting of magnetic order. We prove the critical nature of the
unconventional longitudinal ("Higgs") mode of the ordered phase by damping it
thermally. We demonstrate the development of two types of criticality, quantum
and classical, and use their static and dynamic scaling properties to conclude
that quantum and thermal fluctuations can behave largely independently near a
QCP.Comment: 6 pages, 4 figures. Original version, published version available
from Nature Physics websit
Resonances in and
A partial wave analysis is presented of and
from a sample of 58M events in the BES II detector. The
is observed clearly in both sets of data, and parameters of the
Flatt\' e formula are determined accurately: (stat)
(syst) MeV/c, MeV/c, . The data also exhibit a strong peak
centred at MeV/c. It may be fitted with and a
dominant signal made from interfering with a smaller
component. There is evidence that the signal is
resonant, from interference with . There is also a state in with MeV/c and
MeV/c; spin 0 is preferred over spin 2. This state, , is
distinct from . The data contain a strong peak due to
. A shoulder on its upper side may be fitted by interference
between and .Comment: 17 pages, 6 figures, 1 table. Submitted to Phys. Lett.
First Measurements of eta_c Decaying into K^+K^-2(pi^+pi^-) and 3(pi^+pi^-)
The decays of eta_c to K^+K^-2(pi^+pi^-) and 3(pi^+pi^-) are observed for the
first time using a sample of 5.8X10^7 J/\psi events collected by the BESII
detector. The product branching fractions are determined to be B(J/\psi-->gamma
eta_c)*B(eta_c-->K^+K^-pi^+pi^-pi^+pi^-)=(1.21+-0.32+-
0.23)X10^{-4}, and (J/\psi-->gamma eta_c)*
B(eta_c-->pi^+pi^-pi^+pi^-pi^+pi^-)= (2.59+-0.32+-0.48)X10^{-4}. The upper
limit for eta_c-->phi pi^+pi^-pi^+pi^- is also obtained as B(J/\psi-->gamma
eta_c)*B(eta_c--> phi pi^+pi^-pi^+pi^-)< 6.03 X10^{-5} at the 90% confidence
level.Comment: 11 pages, 4 figure
Measurement of the Branching Fraction of J/psi --> pi+ pi- pi0
Using 58 million J/psi and 14 million psi' decays obtained by the BESII
experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The
result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous
measurements.Comment: 9 pages, 8 figures, RevTex
Search for K_S K_L in psi'' decays
K_S K_L from psi'' decays is searched for using the psi'' data collected by
BESII at BEPC, the upper limit of the branching fraction is determined to be
B(psi''--> K_S K_L) < 2.1\times 10^{-4} at 90% C. L. The measurement is
compared with the prediction of the S- and D-wave mixing model of the
charmonia, based on the measurements of the branching fractions of J/psi-->K_S
K_L and psi'-->K_S K_L.Comment: 5 pages, 1 figur
First observation of psi(2S)-->K_S K_L
The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data
collected with the Beijing Spectrometer (BESII) at the Beijing Electron
Positron Collider (BEPC); the branching ratio is determined to be
B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with
J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the
prediction of the perturbative QCD ``12%'' rule. The result, together with the
branching ratios of psi(2S) decays to other pseudoscalar meson pairs
(\pi^+\pi^- and K^+K^-), is used to investigate the relative phase between the
three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.Comment: 5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
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