5 research outputs found
Effect of Etching on Electron–Hole Recombination in Sr-Doped NaTaO<sub>3</sub> Photocatalysts
Sodium
tantalate (NaTaO<sub>3</sub>) photocatalysts doped with
Sr<sup>2+</sup> produce core–shell-structured NaTaO<sub>3</sub>–SrSr<sub>1/3</sub>Ta<sub>2/3</sub>O<sub>3</sub> solid solutions
able to split water efficiently, when prepared via the solid-state
method. In this study, the photocatalysts were chemically etched to
examine the different roles of the core and shell with respect to
the recombination of electrons and holes. Under excitation by Hg–Xe
lamp irradiation, the steady-state population of electrons in the
core–shell-structured photocatalyst with a bulk Sr concentration
of 5 mol % increased by 130 times relative to that of the undoped
photocatalyst. During etching for the first 10 min, the shell detached
from the top of the core, and the electron population in the uncovered
core further increased by 40%. This population enhancement indicates
that electrons are excited in the core and recombined in the shell.
Etching up to 480 min resulted in the reduction of the electron population.
To interpret the population reduction in this stage of etching, a
Sr concentration gradient that controls the electron population in
the core is proposed
Highly Enantioselective Total Synthesis of (+)-Isonitramine
A new efficient enantioselective synthetic method of (+)-isonitramine is reported. (+)-Isonitramine was obtained in 12 steps (98% ee and 43% overall yield) from δ-valerolactam <i>via</i> enantioselective phase-transfer catalytic alkylation, Dieckman condensation, and diastereoselective reduction as key steps
Green Synthesis of Anatase TiO<sub>2</sub> Nanocrystals with Diverse Shapes and their Exposed Facets-Dependent Photoredox Activity
The
exposed facets of a crystal are known to be one of the key
factors to its physical, chemical and electronic properties. Herein,
we demonstrate the role of amines on the controlled synthesis of TiO<sub>2</sub> nanocrystals (NCs) with diverse shapes and different exposed
facets. The chemical, physical and electronic properties of the as-synthesized
TiO<sub>2</sub> NCs were evaluated and their photoredox activity was
tested. It was found that the intrinsic photoredox activity of TiO<sub>2</sub> NCs can be enhanced by controlling the chemical environment
of the surface, i.e.; through morphology evolution. In particular,
the rod shape TiO<sub>2</sub> NCs with ∼25% of {101} and ∼75%
of {100}/{010} exposed facets show 3.7 and 3.1 times higher photocatalytic
activity than that of commercial Degussa P25 TiO<sub>2</sub> toward
the degradation of methyl orange and methylene blue, respectively.
The higher activity of the rod shape TiO<sub>2</sub> NCs is ascribed
to the facetsphilic nature of the photogenerated carriers within the
NCs. The photocatalytic activity of TiO<sub>2</sub> NCs are found
to be in the order of {101}+{100}/{010} (nanorods) > {101}+{001}+{100}/{010}
(nanocuboids and nanocapsules) > {101} (nanoellipsoids) > {001}
(nanosheets)
providing the direct evidence of exposed facets-depended photocatalytic
activity
Construction of Chiral α‑Amino Quaternary Stereogenic Centers via Phase-Transfer Catalyzed Enantioselective α‑Alkylation of α‑Amidomalonates
An
efficient enantioselective synthetic method for α-amido-α-alkylmalonates
via phase-transfer catalytic α-alkylation was successfully developed.
The α-alkylation of α-amidomalonates under phase-transfer
catalytic conditions (50% KOH, toluene, −40 °C) in the
presence of (<i>S</i>,<i>S</i>)-3,4,5-trifluorophenyl-NAS
bromide afforded the corresponding α-amido-α-alkylmalonates
in high chemical yields (up to 99%) and optical yields (up to 97%
ee), which could be readily converted to versatile chiral intermediates
bearing α-amino quaternary stereogenic centers. The synthetic
potential of this methodology was demonstrated via the synthesis of
chiral azlactone, oxazoline, and unnatural α-amino acid
DataSheet_1_Combined impact of the inter and intra-patient variability of tacrolimus blood level on allograft outcomes in kidney transplantation.docx
IntroductionTacrolimus (TAC) has been widely used as an immunosuppressant after kidney transplantation (KT); however, the combined effects of intra-patient variability (IPV) and inter-patient variability of TAC-trough level (C0) in blood remain controversial. This study aimed to determine the combined impact of TAC-IPV and TAC inter-patient variability on allograft outcomes of KT.MethodsIn total, 1,080 immunologically low-risk patients who were not sensitized to donor human leukocyte antigen (HLA) were enrolled. TAC-IPV was calculated using the time-weighted coefficient variation (TWCV) of TAC-C0, and values > 30% were classified as high IPV. Concentration-to-dose ratio (CDR) was used for calculating TAC inter-patient variability, and CDR ResultsThe incidences of DCGL, BPAR, and overall graft loss were the highest in the high-IPV/RM group. In addition, a high IPV/RM was identified as an independent risk factor for DCGL. The hazard ratio of high IPV/RM for DCGL and the incidence of active antibody-mediated rejection were considerably increased in the PRA-positive subgroup.DiscussionHigh IPV combined with RM (inter-patient variability) was closely related to adverse allograft outcomes, and hence, more attention must be given to pre-transplant PRA-positive patients.</p