Phenol
is one of the most important chemicals in industry. One-step
selective benzene hydroxylation is an attractive yet challenging method
for phenol production, especially when such a reaction can be driven
by solar energy. Herein, we reported that a highly selective benzene
hydroxylation to phenol can be achieved over two Fe-based metal–organic
frameworks [MIL-100(Fe) and MIL-68(Fe)] under visible light irradiations
using hydrogen peroxide (H2O2) as an oxidant.
An optimal benzene conversion of 30.6% was achieved with a H2O2:benzene ratio of 3:4 over MIL-100(Fe) after 24 h irradiations.
ESR results and the kinetic studies suggested that a successful coupling
of the photocatalysis of Fe–O clusters in Fe-based metal–organic
frameworks (MOFs) with
a Fenton-like route is involved in this benzene hydroxylation process.
The comparison of the reaction over MIL-100(Fe) and MIL-68(Fe) reveals
that the structure of MOFs significantly influences the photocatalytic
efficiency. Because the composition and the structure of MOFs are
highly tunable, this study highlights the great potential of using
Fe-based MOFs for photocatalytic benzene hydroxylation to form phenol,
which may result in an economical, sustainable, and thus green process
for phenol production.
HCO(3)(-) plays critically important roles during virtually the entire process of reproduction in mammals, including spermatogenesis, sperm capacitation, fertilization, and development of early stage embryos. Therefore, the acid-base balance in the male and female reproductive tracts must be finely modulated. The fluid milieu in the epididymis is acidic, containing very low concentration of HCO(3)(-). In this acidic low HCO(3)(-) environment, mature sperm are rendered quiescent in the epididymis. In contrast, the luminal fluid in the female uterus and oviduct is alkaline, with very high concentration of HCO(3)(-) that is essential for sperm to fulfill fertilization. HCO(3)(-) transporter of solute carrier 4 (SLC4) and SLC26 families represent the major carriers for HCO(3)(-) transport across the plasma membrane. These transporters play critical roles in intracellular pH regulation and transepithelial HCO(3)(-) transport. The physiological roles of these transporters in mammalian reproduction are of fundamental interest to investigators. Here we review recent progress in understanding the expression of HCO(3)(-) transporters in reproductive tract tissues as well as the physiological roles of these transporters in mammalian reproduction.
Na(+)-coupled HCO(3)(-) transporters (NCBTs) of the SLC4 family play critical roles in pH regulation as well as transepithelial HCO(3)(-) transport. We systematically examined, in the mouse reproductive tract tissues, the mRNA expression of five NCBTs as well as the five NBCe1 (Slc4a4) variants NBCe1-A through -E, of which NBCe1-D and NBCe1-E are novel. Cloning of NBCe1-D and NBCe1-E, both lacking a 27-nucleotide cassette I, reveals a novel alternative splicing unit in the mouse Slc4a4 gene. Transcripts of Slc4a4 lacking cassette I are expressed in diverse murine tissues as shown by RT-PCR analysis and in diverse tissues of other vertebrate species as shown by blast against GenBank database. Genomic sequence analysis indicates that cassette I of SLC4A4 is conserved in all NCBT genes except for SLC4A5, which presumably lost cassette I during its evolution. Our present study represents an important step towards understanding the molecular physiology of NBCe1, and presumably other NCBTs.
The application of
the serpentine mesh layout in stretchable electronics
provides a feasible method to achieve the desired stretchability by
structural design instead of modifying the intrinsic mechanical properties
of the applied materials. However, previous works using the serpentine
layout mainly focused on the optimization of structural stretchability.
In this paper, the serpentine mesh design concept is used to transform
the high-performance but hard-to-stretch piezoelectric film into a
stretchable form. The serpentine layout design strategies for the
piezoelectric film, which aim at not only desired stretchability but
also high utilization of the strain in the piezoelectric film during
deformation, are discussed with experimental and computational results.
A stretchable micromotion sensor with high sensitivity is realized
using the piezoelectric film with a serpentine layout. Human voice
recognition applications of the sensor, including speech pattern recognition
with machine learning, are demonstrated with the sensor integrated
with a wireless module. The stretchable micromotion sensor with a
serpentine layout illustrates the broader application of serpentine
layout design in the functional materials of stretchable electronics,
which can further extend the range of available functional materials
for novel stretchable electronic devices.
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