171 research outputs found
Supplemental Material, Executive_Summary_ASI-18-015_121019_v3 - Feeling Manipulated: How Tip Request Sequence Impacts Customers and Service Providers?
Supplemental Material, Executive_Summary_ASI-18-015_121019_v3 for Feeling Manipulated: How Tip Request Sequence Impacts Customers and Service Providers? by Nathan Warren, Sara Hanson and Hong Yuan in Journal of Service Research</p
Supplemental Material, Please_share_with_ten_academics_ASI-18-015)_120819 - Feeling Manipulated: How Tip Request Sequence Impacts Customers and Service Providers?
Supplemental Material, Please_share_with_ten_academics_ASI-18-015)_120819 for Feeling Manipulated: How Tip Request Sequence Impacts Customers and Service Providers? by Nathan Warren, Sara Hanson and Hong Yuan in Journal of Service Research</p
Synthesis of Two-Dimensional Zeolite Nanosheets Applied to the Catalytic Cracking of a Waste Cooking Oil Model Compound to Produce Light Olefins
Hierarchical zeolites can provide multidimensional spatial
networks
and, therefore, have significant potential as catalysts for the cracking
of biomass to generate light olefins. The present work synthesized
the diquaternary ammonium-type surfactant [C18H37–N+(CH3)2–(CH2)6–N+(CH3)2–C6H13]Br2, incorporating
hydrophobic 18-carbon alkyl groups for usage as a structure-directing
agent. This compound was subsequently used to prepare nanosheets of
a hierarchical ZSM-5 two-dimensional zeolite (HNZSM-5) through a one-pot
hydrothermal method. The crystal phase, morphology, and hierarchical
structure of the HNZSM-5 were analyzed using various techniques, including
X-ray diffraction, electron microscopy, and N2 adsorption/desorption.
When applied to the catalytic cracking of a waste cooking oil model
compound, the HNZSM-5 exhibited superior activity and stability compared
with a conventional ZSM-5. This performance was attributed to the
more accessible acid sites and unique lamellar structure of the former
material. The HNZSM-5 also outlasted the conventional zeolite, showing
deactivation after 45 h of reaction compared with 20 h, indicating
exceptional stability and excellent resistance to coking
Synthesis and Antitumor Activity of Stearate-<i>g</i>-dextran Micelles for Intracellular Doxorubicin Delivery
Stearate-g-dextran (Dex-SA) was synthesized via an esterification reaction between the carboxyl group of stearic acid (SA) and hydroxyl group of dextran (Dex). Dex-SA could self-assemble to form nanoscaled micelles in aqueous medium. The critical micelle concentration (CMC) depended on the molecular weight of Dex and the graft ratio of SA, which ranged from 0.01 to 0.08 mg mL−1. Using doxorubicin (DOX) as a model drug, the drug encapsulation efficiency (EE%) using Dex-SA with 10 kDa molecular weight of Dex and 6.33% graft ratio of SA could reach up to 84%. In vitro DOX release from DOX-loaded Dex-SA micelles (Dex-SA/DOX) could be prolonged to 48 h, and adjusted by a different molecular weight of Dex, the graft ratio of SA, or the drug-loading content. Tumor cellular uptake test indicated that Dex-SA micelles had excellent internalization ability, which could deliver DOX into tumor cells. In vitro cytotoxicity tests demonstrated the Dex-SA/DOX micelles could maintain the cytotoxicity of commercial doxorubicin injection against drug-sensitive tumor cells. Moreover, Dex-SA/DOX micelles presented reversal activity against DOX-resistant cells. In vivo antitumor activity results showed that Dex-SA/DOX micelles treatments effectively suppressed the tumor growth and reduced the toxicity against animal body compared with commercial doxorubicin injection
Bimetallic Hierarchical Nanostructured Alumina Material Catalyzes Decarboxylation of Oleic Acid to Produce Long-Chain Alkanes for Bioaviation Kerosene
Standard alumina has only a small number of mesopores,
which is
not conducive to the mass transfer of biomacromolecules and so affects
the catalytic activity in the case that this material is used as a
catalyst substrate. In the present work, hierarchical nanostructured
γ-Al2O3 (HNCγ-Al2O3) assembled from nanosheets was obtained after high-temperature
calcination and a low-temperature hydrothermal treatment of an Al-MOF
precursor. This material had a high Brunauer–Emmett–Teller
(BET) surface area (266.8 cm3/g) and pore volume (0.64
cm3/g) together with abundant mesopores. Both monometallic
and bimetallic Pt/Ni catalysts were prepared using HNCγ-Al2O3 as a carrier and applied to the decarboxylation
of oleic acid to produce C8–C17 alkanes.
Compared with monometallic materials, the introduction of a second
metal increased the quantity and strength of acidic sites on the catalyst.
A synergistic effect obtained by incorporating Pt and Ni in the bimetallic
catalysts increased the number of oxygen vacancies in the materials
and lowered the temperature required to reduce NiOx. At 340 °C, Pt–Ni/Al-1:3 catalyzed the decarboxylation
reaction of oleic acid, giving a yield of the product C8–C17 alkanes of 85.3% after a 4 h reaction
Catalytic Oxidation of Glycerol over Pt Supported on MOF-Derived Carbon Nanosheets
A series of nitrogen-doped porous carbon nanosheets (NPCNs)
doped
with transition-metal-supported Pt catalysts were prepared by colloidal
deposition and evaluated for the selective oxidation of glycerol to
glyceric acid (GLYA) under nonalkaline conditions. The transition
metal contained in the catalyst was found to affect its performance
and selectivity for GLYA, with the Pt/Zr@NPCN catalyst showing the
highest catalytic activity and selectivity. These materials were characterized
using Brunauer–Emmett–Teller surface area analysis,
transmission electron microscopy, X-ray diffraction, X-ray photoelectron
spectroscopy, and CO2 temperature-programmed desorption.
The results showed that the small size of the Pt nanoparticles, the
interaction between the Pt nanoparticles and the support, and the
unique textural properties of the catalyst all promoted glycerol conversion
and GLYA selectivity. A Zr concentration of 1.5 wt % and a support
preparation temperature of 800 °C were found to provide a catalyst
with the optimal performance that exhibited a glycerol conversion
and selectivity for GLYA of 68.62 and 77.29%, respectively, at an
initial O2 pressure of 10 bar and 60 °C after 6 h.
Even after being recycled five times, this material provided a GLYA
selectivity of approximately 75%, although the glycerol conversion
decreased from 68 to 50%. The insights may provide new suggestions
on the design of efficient support for the selective oxidation of
polyols
MOFs-Derived Mn<sub><i>x</i></sub>O<sub><i>y</i></sub>C<sub><i>z</i></sub> Supported Bimetallic Au–Pt Catalyst for the Catalytic Oxidation of Glycerol to Glyceric Acid
The specific structure of the support and the interactions
between
the catalyst components can lead to electron transfer, which in turn
could affect the catalytic performance in heterogeneous catalytic
reactions. In this paper, we have successfully prepared MnxOyCz composite materials from the calcination of the Mn-organic
framework. Then bimetallic Au–Pt nanoparticles (NPs) were supported
onto MnxOyCz via the colloidal-deposition method.
These catalysts were tested in the selective oxidation of glycerol
to glyceric acid under basic conditions. The results demonstrated
that the catalytic activity of the bimetallic Au–Pt/MnxOyCz catalyst is considerably superior to those of the
monometallic (Au and Pt) supported catalysts. Under the optimized
conditions, 100% of glycerol can convert with 57.3% selectivity of
glyceric acid. Multicharacterizations showed that the strong interaction
between Au and Pt in the Au–Pt/MnxOyCz catalyst
can enhance the dispersion of Au–Pt alloy NPs, promoting the
electronic coupling effect on the metal surface. At the same time,
the rich oxygen vacancies in this catalyst can facilitate the activation
of oxygen, which causes the Au–Pt/MnxOyCz catalyst to show better catalytic activity. Specifically, the interaction
between Au and Pt not only decreases the particle size of the Au–Pt
alloy NPs but also promotes the reduction of Mn-based oxides and the
mobility of oxygen. The absence of Au leads to a decrease in Pt 4f7/2 binding energy, resulting in an enrichment of electrons
at the Pt active site and enhancing the oxidation ability of the primary
hydroxyl group. In addition, the Au–Pt/MnxOyCz catalyst showed excellent stability without substantial loss of
activity after being recycled five times. The insights and methodology
may provide some new guidance for the reasonable design of bimetallic
catalysts for the catalytic oxidation of biopolyols under mild conditions
Spacer Control the Dynamic of Triplex Formation between Oligonucleotide-Modified Gold Nanoparticles
A novel method was developed to control the dynamic of triplex formation between oligonucleotide-modified gold nanoparticles in the presence of complementary strand. The solution containing the oligonucleotide 5′-SH-ACA CAC ACA CAC CTT TCT TTC CTT TCT TTC-3′(oligo-1)-modified gold nanoparticles was red in color. Due to triplex formation, there was a tiny change in color on addition of the complementary oligonucleotide 5′-GAA AGA AAG GAA AGA AAG-3′(oligo-3). The addition of oligonucleotide 5′-GTG TGT GTG TGT-3′(oligo-2) induced the spacer portion of oligo-1 to change from single strand to rigid duplex structure and protrude from the surface of the gold colloid, removing the physisorption between oligo-1 and the gold nanoparticles successfully. Therefore, when the oligo-2 was added accompanied by oligo-3 at pH 5.6 and 6.0 μM spermine, larger aggregates were formed and the color of the solution changed from red to blue within 20 min. The oligo-2 hybridized with the spacer portion of oligo-1 and had no effect on the stability of triplex DNA; thereby, the melting temperatures of the triplex DNA were 51 and 53 °C in the absence and presence of oligo-2, respectively. Oligo-3 played a crucial role in the triplex formation between nanoparticles. When oligo-3 was replaced with 5′-GAA AGA AAG TAA AGA AAG-3′ (oligo-4, single-base mismatched) and 5′-GAA AGT AAG GAA TGA AAG-3′ (oligo-5, double-base mismatched), respectively, the melting temperature decreased from 53 to 41 °C and eventually to 33 °C
Targeting High Expressed α<sub>5</sub>β<sub>1</sub> Integrin in Liver Metastatic Lesions To Resist Metastasis of Colorectal Cancer by RPM Peptide-Modified Chitosan-Stearic Micelles
Liver
metastasis is a leading death cause in colorectal cancer.
The pathological differences between orthotopic tumors and metastatic
lesions increased the therapeutic difficulty of metastasis. Herein,
the α<sub>5</sub>β<sub>1</sub> integrin receptor expression
on metastatic cells was first measured, the result showed that metastatic
cells expressed the α<sub>5</sub>β<sub>1</sub> integrin
higher than that of the original cells from orthotopic tumors. Afterward,
RPM peptide-modified chitosan-stearic (RPM-CSOSA) was designed based
on α<sub>5</sub>β<sub>1</sub> integrin expression. The
cytotoxicity and resistance to migration and the invasion ability
of the targeting drug delivery system loading doxorubicin (DOX) and
curcumin (CUR) were evaluated in vitro. The metastatic inhibition
of the targeting drug delivery system was also investigated in HT29
liver metastatic models. The modified RPM peptide could increase the
cellular internalization of CSOSA micelles in metastatic tumor cells
and endothelial cells mediated by α<sub>5</sub>β<sub>1</sub> integrin. The synergistic effects of RPM-CSOSA/DOX and RPM-CSOSA/CUR
could obviously inhibit migratory and invasive abilities of HT29 cells
and endothelial cells. Moreover, the RPM-CSOSA/DOX&RPM-CSOSA/CUR
could obviously decrease the number of metastatic sites by 86.96%,
while CSOSA/DOX&CSOSA/CUR decreased liver metastasis by 66.58%
compared with that in the saline group. In conclusion, the RPM peptide-modified
drug delivery system may provide insights into targeting the metastatic
cells overexpressing the α<sub>5</sub>β<sub>1</sub> integrin,
and it has the potential to inhibit liver metastasis of colorectal
cancer
Additional file 1 of Sacubitril/valsartan inhibits the proliferation of vascular smooth muscle cells through notch signaling and ERK1/2 pathway
Supplementary Material
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