27 research outputs found
Epitaxial Growth of Twinned AuāPt CoreāShell Star-Shaped Decahedra as Highly Durable Electrocatalysts
Pt epitaxial layer on a nanoparticle
with twinned structure and well-defined shape is highly desirable
in order to achieve high performance in both catalytic activity and
durability toward oxygen reduction reaction (ORR). However, it remains
tremendously challenging to produce conformal, heterogeneous, twinned
nanostructures due to the high internal strain and surface energy
of Pt. In addition, these twinned nanostructures may be subject to
degradation in highly corrosive ORR environments due to the high energy
of twin boundary. Here we report the synthesis of AuāPt coreāshell
star-shaped decahedra bounded mainly by {111} facets, in which Pt
shells with controlled thickness epitaxially grew on Au cores with
a 5-fold twinned structure. The incorporation of the amine group decreases
the surface energy of Pt by strong adsorption and thus facilitates
the epitaxial growth of Pt on Au core instead of the dendritic growth.
In addition, Br<sup>ā</sup> ion could largely stabilize the
{111} facets of Pt, which prevent the formation of spherical nanoparticles.
The AuāPt coreāshell decahedra with thicker Pt shell
exhibited enhanced ORR properties in terms of activity and durability.
Specifically, AuPt<sub>1.03</sub> star-shaped decahedra achieved the
highest mass activity (0.94 mA/Ī¼g<sub>Pt</sub>) and area activity
(1.09 mA/cm<sup>2</sup><sub>Pt</sub>), which is ā¼6.7 and 5
times, respectively, as high as those of the commercial Pt/C (ETEK).
Significantly, such star-shaped decahedra were highly stable with
ā¼10% loss in area activity and ā¼20% loss in mass activity
after 30āÆ000 CV cycles in O<sub>2</sub> saturated acid solution
In situ Study of Oxidative Etching of Palladium Nanocrystals by Liquid Cell Electron Microscopy
Oxidative etching
has widely prevailed in the synthesis of a crystal
and played a critical role in determining the final growth behavior.
In this Letter, we report an in situ microscopic study on the oxidative
etching of palladium cubic nanocrystals by liquid cell scanning transmission
electron microscopy. The etching was realized with oxidative radiation
reactants from electronāwater interaction in the presence of
Br<sup>ā</sup> ions. Dissolution dynamics of monodispersed
and aggregated nanocrystals were both investigated and compared. Analyses
on the dissolution kinetics of nanocrystals and the diffusion kinetics
of the dissolved agents were carried out based on the scanning transmission
electron microscopy characterizations. The results presented here
pave a way toward the quantitative understanding of the oxidative
etching reaction and its application in the functionally orientated
fabrication of nanocrystals with certain sizes, structures, and morphologies
Comparative Study on the Localized Surface Plasmon Resonance of Boron- and Phosphorus-Doped Silicon Nanocrystals
Localized surface plasmon resonance (LSPR) of doped Si nanocrystals (NCs) is critical to the development of Si-based plasmonics. We now experimentally show that LSPR can be obtained from both B- and P-doped Si NCs in the mid-infrared region. Both experiments and calculations demonstrate that the Drude model can be used to describe the LSPR of Si NCs if the dielectric screening and carrier effective mass of Si NCs are considered. When the doping levels of B and P are similar, the LSPR energy of B-doped Si NCs is higher than that of P-doped Si NCs because B is more efficiently activated to produce free carriers than P in Si NCs. We find that the plasmonic coupling between Si NCs is effectively blocked by oxide at the NC surface. The LSPR quality factors of B- and P-doped Si NCs approach those of traditional noble metal NCs. We demonstrate that LSPR is an effective means to gain physical insights on the electronic properties of doped Si NCs. The current work on the model semiconductor NCs, <i>i.e.</i>, Si NCs has important implication for the physical understanding and practical use of semiconductor NC plasmonics
Epitaxial Growth of Multimetallic Pd@PtM (M = Ni, Rh, Ru) CoreāShell Nanoplates Realized by in Situ-Produced CO from Interfacial Catalytic Reactions
Pt-based
multimetallic coreāshell nanoplates have received great attention
as advanced catalysts, but the synthesis is still challenging. Here
we report the synthesis of multimetallic Pd@PtM (M = Ni, Rh, Ru) nanoplates
including Pd@Pt nanoplates, in which Pt or Pt alloy shells with controlled
thickness epitaxially grow on plate-like Pd seeds. The key to achieve
high-quality Pt-based multimetallic nanoplates is in situ generation
of CO through interfacial catalytic reactions associated with Pd nanoplates
and benzyl alcohol. In addition, the accurate control in a trace amount
of CO is also of great importance for conformal growth of multimetallic
coreāshell nanoplates. The Pd@PtNi nanoplates exhibit substantially
improved activity and stability for methanol oxidation reaction (MOR)
compared to the Pd@Pt nanoplates and commercial Pt catalysts due to
the advantages arising from plate-like, coreāshell, and alloy
structures
Image_4_Serum HBsAg and HBcrAg is associated with inflammation in HBeAg-positive chronic hepatitis B patients.tiff
Backgrounds & aimsLiver inflammation is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. To replace biopsy, additional non-invasive biomarkers to diagnose and grade liver necroinflammation are urgently required in clinical practice.MethodNinety-four CHB patients, including 74 HBeAg-positive and 20 HBeAg-negative patients, were enrolled and started entecavir or adefovir therapy. Serum HBV RNA, HBV DNA, HBsAg, hepatitis B core-related antigen (HBcrAg), ALT and AST levels, as well as intrahepatic HBV DNA and cccDNA were measured at baseline and during treatment. Liver inflammation was assessed at baseline and month 60 by liver biopsy. Inflammation regression was defined as a ā„1-grade decrease according to the Scheuer scoring system.ResultsIn HBeAg-positive CHB patients, at baseline, serum HBsAg and HBcrAg levels negatively correlated with inflammation grade, while ALT and AST levels positively correlated with inflammation grade. AST plus HBsAg exhibited excellent diagnostic ability for significant inflammation with an AUROC of 0.896. After 60 months of antiviral treatment, almost all the patientsā liver inflammation ameliorated to G1, and no patients had inflammation progression.ConclusionBesides ALT and AST, serum HBsAg and HBcrAg correlated with inflammation grade in HBeAg-positive CHB patients before NAs treatment. Moreover, the combination of HBsAg and AST exhibited excellent diagnostic ability for significant inflammation.</p
DataSheet_1_Serum HBsAg and HBcrAg is associated with inflammation in HBeAg-positive chronic hepatitis B patients.docx
Backgrounds & aimsLiver inflammation is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. To replace biopsy, additional non-invasive biomarkers to diagnose and grade liver necroinflammation are urgently required in clinical practice.MethodNinety-four CHB patients, including 74 HBeAg-positive and 20 HBeAg-negative patients, were enrolled and started entecavir or adefovir therapy. Serum HBV RNA, HBV DNA, HBsAg, hepatitis B core-related antigen (HBcrAg), ALT and AST levels, as well as intrahepatic HBV DNA and cccDNA were measured at baseline and during treatment. Liver inflammation was assessed at baseline and month 60 by liver biopsy. Inflammation regression was defined as a ā„1-grade decrease according to the Scheuer scoring system.ResultsIn HBeAg-positive CHB patients, at baseline, serum HBsAg and HBcrAg levels negatively correlated with inflammation grade, while ALT and AST levels positively correlated with inflammation grade. AST plus HBsAg exhibited excellent diagnostic ability for significant inflammation with an AUROC of 0.896. After 60 months of antiviral treatment, almost all the patientsā liver inflammation ameliorated to G1, and no patients had inflammation progression.ConclusionBesides ALT and AST, serum HBsAg and HBcrAg correlated with inflammation grade in HBeAg-positive CHB patients before NAs treatment. Moreover, the combination of HBsAg and AST exhibited excellent diagnostic ability for significant inflammation.</p
Image_2_Serum HBsAg and HBcrAg is associated with inflammation in HBeAg-positive chronic hepatitis B patients.tiff
Backgrounds & aimsLiver inflammation is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. To replace biopsy, additional non-invasive biomarkers to diagnose and grade liver necroinflammation are urgently required in clinical practice.MethodNinety-four CHB patients, including 74 HBeAg-positive and 20 HBeAg-negative patients, were enrolled and started entecavir or adefovir therapy. Serum HBV RNA, HBV DNA, HBsAg, hepatitis B core-related antigen (HBcrAg), ALT and AST levels, as well as intrahepatic HBV DNA and cccDNA were measured at baseline and during treatment. Liver inflammation was assessed at baseline and month 60 by liver biopsy. Inflammation regression was defined as a ā„1-grade decrease according to the Scheuer scoring system.ResultsIn HBeAg-positive CHB patients, at baseline, serum HBsAg and HBcrAg levels negatively correlated with inflammation grade, while ALT and AST levels positively correlated with inflammation grade. AST plus HBsAg exhibited excellent diagnostic ability for significant inflammation with an AUROC of 0.896. After 60 months of antiviral treatment, almost all the patientsā liver inflammation ameliorated to G1, and no patients had inflammation progression.ConclusionBesides ALT and AST, serum HBsAg and HBcrAg correlated with inflammation grade in HBeAg-positive CHB patients before NAs treatment. Moreover, the combination of HBsAg and AST exhibited excellent diagnostic ability for significant inflammation.</p
Copolymers of Bis-Diketopyrrolopyrrole and Benzothiadiazole Derivatives for High-Performance Ambipolar Field-Effect Transistors on Flexible Substrates
We
develop an āacceptor dimerizationā strategy by a bis-diketopyrrolopyrrole
(2DPP) for an ambipolar organic semiconductor. Copolymers of 2DPP
and benzothiadiazole (BTz) derivatives, P2DPP-BTz and P2DPP-2FBTz,
are designed and synthesized. Both of the polymers exhibit narrow
optical bandgaps of ca. 1.30 eV. The strong electron-withdrawing property
of 2DPP results in low-lying lowest unoccupied molecular orbital (LUMO)
energy levels of the polymers, improving the electron mobilities.
2D grazing incident X-ray diffraction and atomic force microscopy
indicate that the P2DPP-BTz exhibits a small ĻāĻ
stacking distance of 3.59 Ć
and a smooth interface, thus promoting
high mobility. To take full advantage of the flexibility of organic
semiconductors, flexible field-effect transistors (FETs) were fabricated
on polyĀ(ethylene terephthalate) (PET) substrates. The FETs based on
P2DPP-BTz show high performance with hole and electron mobilities
of 1.73 and 2.58 cm<sup>2</sup> V<sup>ā1</sup> s<sup>ā1</sup>, respectively. Our results demonstrate that the 2DPP acceptor is
a promising building block for high-mobility ambipolar polymers
Image_1_Serum HBsAg and HBcrAg is associated with inflammation in HBeAg-positive chronic hepatitis B patients.tiff
Backgrounds & aimsLiver inflammation is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. To replace biopsy, additional non-invasive biomarkers to diagnose and grade liver necroinflammation are urgently required in clinical practice.MethodNinety-four CHB patients, including 74 HBeAg-positive and 20 HBeAg-negative patients, were enrolled and started entecavir or adefovir therapy. Serum HBV RNA, HBV DNA, HBsAg, hepatitis B core-related antigen (HBcrAg), ALT and AST levels, as well as intrahepatic HBV DNA and cccDNA were measured at baseline and during treatment. Liver inflammation was assessed at baseline and month 60 by liver biopsy. Inflammation regression was defined as a ā„1-grade decrease according to the Scheuer scoring system.ResultsIn HBeAg-positive CHB patients, at baseline, serum HBsAg and HBcrAg levels negatively correlated with inflammation grade, while ALT and AST levels positively correlated with inflammation grade. AST plus HBsAg exhibited excellent diagnostic ability for significant inflammation with an AUROC of 0.896. After 60 months of antiviral treatment, almost all the patientsā liver inflammation ameliorated to G1, and no patients had inflammation progression.ConclusionBesides ALT and AST, serum HBsAg and HBcrAg correlated with inflammation grade in HBeAg-positive CHB patients before NAs treatment. Moreover, the combination of HBsAg and AST exhibited excellent diagnostic ability for significant inflammation.</p
Table_1_Serum HBsAg and HBcrAg is associated with inflammation in HBeAg-positive chronic hepatitis B patients.docx
Backgrounds & aimsLiver inflammation is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. To replace biopsy, additional non-invasive biomarkers to diagnose and grade liver necroinflammation are urgently required in clinical practice.MethodNinety-four CHB patients, including 74 HBeAg-positive and 20 HBeAg-negative patients, were enrolled and started entecavir or adefovir therapy. Serum HBV RNA, HBV DNA, HBsAg, hepatitis B core-related antigen (HBcrAg), ALT and AST levels, as well as intrahepatic HBV DNA and cccDNA were measured at baseline and during treatment. Liver inflammation was assessed at baseline and month 60 by liver biopsy. Inflammation regression was defined as a ā„1-grade decrease according to the Scheuer scoring system.ResultsIn HBeAg-positive CHB patients, at baseline, serum HBsAg and HBcrAg levels negatively correlated with inflammation grade, while ALT and AST levels positively correlated with inflammation grade. AST plus HBsAg exhibited excellent diagnostic ability for significant inflammation with an AUROC of 0.896. After 60 months of antiviral treatment, almost all the patientsā liver inflammation ameliorated to G1, and no patients had inflammation progression.ConclusionBesides ALT and AST, serum HBsAg and HBcrAg correlated with inflammation grade in HBeAg-positive CHB patients before NAs treatment. Moreover, the combination of HBsAg and AST exhibited excellent diagnostic ability for significant inflammation.</p