52 research outputs found
Biosynthesis of <sup>15</sup>N<sub>3</sub>-Labeled Enniatins and Beauvericin and Their Application to Stable Isotope Dilution Assays
The first stable isotope dilution assay for the determination
of
enniatins A, A1, B, and B1 and beauvericin was developed. The <sup>15</sup>N<sub>3</sub>-labeled enniatins and beauvericin were biosynthesized
by feeding two Fusarium strains Na<sup>15</sup>NO<sub>3</sub> and subsequently isolated from the fungal
culture. The chemical structures of the biosynthesized products were
characterized by LC-MS/MS and <sup>1</sup>H NMR. Standard solutions
of <sup>15</sup>N<sub>3</sub>-labeled beauvericin, enniatin A, and
enniatin A1 were accurately quantitated by quantitative NMR. On the
basis of the use of the labeled products as internal standards, stable
isotope dilution assays were developed and applied to various food
samples using LC-MS/MS. The sample extracts were directly injected
without any tedious cleanup procedures. The limits of detection were
3.9, 2.6, 3.7, 1.9, and 4.4 μg/kg for enniatins A, A1, B, and
B1 and beauvericin, respectively. Limits of quantitation were 11.5
(enniatin A), 7.6 (enniatin A1), 10.9 (enniatin B), 5.8 (enniatin
B1), and 13.1 μg/kg (beauvericin). Recoveries were within the
range between 90 and 120%, and good intraday and interday precisions
with coefficients of variation between 1.35 and 8.61% were obtained.
Thus, the stable isotope dilution assay presented here is similarly
sensitive and precise but more accurate than assays reported before.
Analyses of cereals and cereal products revealed frequent contaminations
of barley, wheat, rye, and oats with enniatins B and B1, whereas beauvericin
was not quantifiable
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Effect of Cobalt Doping Concentration on the Crystalline Structure and Magnetic Properties of Monodisperse Co<sub><i>x</i></sub>Fe<sub>3–<i>x</i></sub>O<sub>4</sub> Nanoparticles within Nonpolar and Aqueous Solvents
In this work, we investigate the effect of cobalt substitution
on the size evolution, crystal structure, and magnetic properties
of Fe<sub>3</sub>O<sub>4</sub> nanoparticles. Monodisperse Co<sub><i>x</i></sub>Fe<sub>3–<i>x</i></sub>O<sub>4</sub> nanoparticles were prepared, using a one-step method, by
direct heating process of ironÂ(III) and cobaltÂ(II) acetylacetonates
in high-boiling-point inert organic solvent. The quantities of precursors
added were based on stoichiometric Fe/Co ratio of desired ferrite.
Elemental analyses ICP-AES evidenced successful cobalt doping. The
doped particles showed a cobalt-deficient composition. Transmission
electron microscopy demonstrated the large changes of particle size
as a function of cobalt doping. The magnetization measurements showed
an unchanged saturation magnetization only up to <i>x</i> = 0.24, beyond which it significantly decreased. To make the as-synthesized
nanoparticles suitable for biomedical applications, oleic acid ligands
are exchanged with caffeic acid molecules leading to stable nanoparticles
in physiological conditions
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Fabricating 3D Moisture- and NIR Light-Responsive Actuators by a One-Step Gradient Stress-Relaxation Process
Polymeric materials that can actuate under the stimulation
of environmental
signals have attracted considerable attention in fields including
artificial muscles, soft robotics, implantable devices, etc. To date,
the improvement of shape-changing flexibility is mainly limited by
their unchangeable shapes and structural and compositional distributions.
In this work, we report a one-step treatment process to convert 2D
poly(ethylene oxide)/sodium alginate/tannic acid thin films into 3D-shaped
moisture- and NIR light-responsive actuators. Spatial surface wetting
of the film leads to the release of residual stress generated in film
formation in a gradient manner, which drives the wetted regions to
bidirectionally bend. By controlling the position and bending amplitude
of the wetted regions, designated 3D shapes can be obtained. Moreover,
Fe3+ ions in the aqueous solution used for surface wetting
can coordinate with carboxylate groups in sodium alginate chains to
form a gradient cross-linking network. This gradient network can not
only stabilize the resulting 3D shape but also render the film with
moisture-responsive morphing behaviors. Fe3+ ions can also
self-assemble with tannic acid molecules to form photothermal aggregates,
making the film responsive to NIR light. We further show that films
with versatile 3D shapes and different modes of deformation can be
fabricated by a one-step treatment process. This strategy is convenient
and extendable to develop 3D-shaped polymer actuators with flexible
shape-changing behaviors
Novel Waterborne UV-Curable Hyperbranched Polyurethane Acrylate/Silica with Good Printability and Rheological Properties Applicable to Flexographic Ink
Novel waterborne UV-curable hyperbranched
polyurethane acrylate/silica
(HBWPUA/SiO<sub>2</sub>) nanocomposites were prepared by a three-step
procedure and sol–gel method. <sup>1</sup>H NMR and <sup>13</sup>C NMR results indicate that HBWPU is successfully synthesized. Surface
tension and contact angle tests both demonstrate the good wettability
of the nanocomposites. Besides, the kinetics of photopolymerization
of HBWPUA/SiO<sub>2</sub> films were analyzed by attenuated total
reflection-Fourier transform infrared spectroscopy, which reveals
that the modified SiO<sub>2</sub> could accelerate the curing speed
of HBWPUA coatings. Thermal gravity analysis indicates that the HBWPUA/SiO<sub>2</sub> hybrid films have a better thermal stability than the pure
HBWPUA cured films. Furthermore, the hybrid films show enhanced pencil
hardness, abrasion resistance, and adhesion. On the basis of the above,
HBWPUA/SiO<sub>2</sub> nanocomposites were finally applied to waterborne
UV-curing flexographic printing ink, which is printed on polyÂ(ethylene
terephthalate) and glass. The nanocomposite presents good rheological
behavior because the ink has a lower <i>Z</i><sub>0</sub>, a higher <i>Z</i><sub>∞</sub>, and the viscosity
rebuild time is 375 s. Three colors (red, yellow, and blue) of ink
were used to test its printing quality, the curing time was below
30 s, and the adhesion was excellent without being stripped. All of
the inks show good water resistance and abrasion resistance. Moreover,
the red and blue inks possess better solid densities than the value
of 1.07 of yellow ink, and are 1.83 and 1.84, respectively. The current
study suggests that the process has promise in applications of food
packages
The efficacy of Jianpi Yiqi therapy for chronic atrophic gastritis: A systematic review and meta-analysis - Fig 3
<p>(a) Risk of bias summary. (b) Risk of bias graph.</p
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