Given a non-increasing function
ψ
, let
Exact
(
ψ
)
be the set of complex numbers which are approximable by complex rational numbers to order
ψ
but to no better order. In this paper, we obtain the ...Hausdorff dimension and the packing dimension of
Exact
(
ψ
)
when
ψ
(
x
)
=
o
(
x
-
2
)
. Moreover, without the condition
ψ
(
x
)
=
o
(
x
-
2
)
, we also prove that the Hausdorff dimension of
Exact
(
ψ
)
is greater than
2
-
τ
/
(
1
-
2
τ
)
when
0
<
τ
=
lim sup
x
→
+
∞
x
2
ψ
(
x
)
is small enough.
Side-chain-type polymer architectures have been extensively studied for development of highly conductive fuel cell membranes. However, the commonly used rigid, hydrophobic spacers (between the ionic ...end-group and polymer backbone) limit self-assembly of ionic side-chains and, therefore, ion transport. Herein, we report a flexible, hydrophilic side-chain-type anion exchange membrane (AEM), where ethylene oxide spacers are incorporated into imidazolium-containing cationic side-chains. AFM and SAXS analysis confirm that the flexible spacers facilitate self-assembly of the ionic side-chains to form continuous conducting channels. Most importantly, both in situ FTIR spectroscopy and molecular dynamic theory simulations indicate that the ethylene oxide spacers are capable of hydrogen bonding to both H 2 O molecules and hydrated OH − ions. This unique auxiliary function facilitates both ion and H 2 O transport during fuel cell operation. The resultant AEM exhibits a peak power density of 437 mW cm −2 at 65 °C when tested in a H 2 /O 2 single-cell anion-exchange membrane fuel cell, which is among the highest reported for comparable side-chain-type AEMs.
Although much progress has been made in the diagnosis and treatment of thoracic aortic dissection (TAD), the overall morbidity and mortality rates of TAD are still high. Therefore, the molecular ...pathogenesis and etiology of TAD need to be elucidated. In this study, we found that histone deacetylase 1 (HDAC1) expression is dramatically higher in the aortic wall of patients with TAD (than that in a normal group) and negatively correlates with the levels of the vascular smooth muscle cell (SMC) contractile‐phenotype markers. Knockdown of HDAC1 upregulated both smooth muscle 22 α (SM22α) and α‐smooth muscle actin (α‐SMA) in platelet‐derived growth factor (PDGF)‐BB‐treated and ‐untreated SMCs. In addition, the knockdown of HDAC1 markedly decreased SMC viability and migration in contrast to the control group under the conditions of quiescence and PDGF‐BB treatment. We also showed that the expression of polycystic kidney disease 1 (PKD1) is decreased in the aortic wall of patients with TAD and negatively correlates with HDAC1 expression. Overexpressed PKD1 obviously increased SM22α and α‐SMA expression and reduced the viability and migration of SMCs, but these effects were attenuated by HDAC1. Furthermore, we demonstrated that HDAC1 serves as an important modulator of the migration and phenotypic switch of SMCs by suppressing the PKD1– mammalian target of the rapamycin signaling pathway. HDAC1 downregulation inhibited media degeneration and attenuated the loss of elastic–fiber integrity in a mouse model of TAD. Our results suggest that HDAC1 might be a new target for the treatment of a macrovascular disease such as TAD.
Mitophagy, a process that selectively removes damaged organelles by autolysosomal degradation, is an early cellular response to ischemia. Mitophagy is activated in both cardiomyocytes and platelets ...during ischemia/reperfusion (I/R) and heart disease conditions. We focus on the molecular regulation of mitophagy and highlight the role of mitophagy in cardioprotection.
The structures of W- and W-Mo-containing high-entropy borides (HEBs) are systematically studied by combining atomic-resolution transmission electron microscopy imaging, electron diffraction, and ...chemical analysis. We reveal that W or W-Mo addition in HEBs leads to segregation of these elements to the grain boundaries (GBs). In the meantime, W- or W-Mo-rich precipitates also form along the GBs. Crystallographic analysis and atomic-scale imaging show that the GB precipitates in both W- and W-Mo-containing HEBs have a cube-on-cube orientation relationship with the matrix. With further strain analysis, the coherency of the precipitate/matrix interface is validated. Nanoindentation tests show that the simultaneous GB segregation and coherent precipitation, as a supplement to the grain hardening, provide additional hardening of the HEBs. Our work provides an in-depth understanding of the GB segregation and precipitation behaviors of HEBs. It suggests that GB engineering could be potentially used for optimizing the performance of high-entropy ceramics.
Phosphoric acid (PA)-doped proton exchange membranes (PEMs) have been prepared from tetrazole-based sulfonated poly (phthalazinone ether sulfone ketone) (AtSPPESK) for high-temperature proton ...exchange membrane fuel cells (HTPEMFCs). The polymer structure is characterized by fourier-transform infrared spectroscopy (FT-IR), lH nuclear magnetic resonance (1HNMR) and elemental analysis (EA). Compared with other PEMs only with tretrazole groups in side chains, this membrane with a proper PA doping capacity exhibits a much higher proton conductivity of 15 mS cm−1 at 150 °C. Both of phthalazinone groups in main chains and tetrazole groups in side chains are facial for PA uniform aggregation. To give an insight into the excellent proton conducting performance, therein, a proton transport mechanism has been proposed involving proton transport within hydrogen bonded PA molecules networks as well as acid-base interactions between tetrazole and phthalazinone groups. Meanwhile, the proper oxidative, conductivity, thermal and mechanical stability suggest that the PA doped PEM can hold as a promising membrane for HTPEMFCs.
Display omitted
•Phosphoric acid (PA)-doped PEMs have been prepared from tetrazole-based PPESK.•Both of phthalazinone and tetrazole groups are facial for PA uniform aggregation.•Proton transport through hydrogen bonded PA networks and acid-base interactions.•The membrane exhibits a proton conductivity of 0.015 S/cm at 150 °C at anhydrous condition.
var.
is a traditional herbal medicine in China. In this study, the anti-inflammatory activities of active ingredients of
var.
were investigated in RAW 264.7 cells and Freund's complete ...adjuvant-induced arthritic rats. Results showed that
-butanol extract exerted antiarthritic potential by reducing paw edema, arthritis score, and altered hematological and biochemical parameters in experimental rats. Phytochemical studies on
-butanol extract resulted in the isolation of five alkaloids (1-5) and five phenylethanoids (6-10). The anti-inflammatory assay of compounds 1-10 on lipopolysaccharide (LPS)-treated RAW 264.7 cells indicated that phenylethanoids 9 and 10 exhibited notable inhibitory activities. The result indicated that compounds 9 and 10 attenuated inflammation by decreasing the production of nuclear factor kappa-B (NF-κB) p65, inhibitory subunit of NF kappa B alpha, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), and inducible nitric oxide synthase in LPS-mediated RAW 264.7 macrophages. Phenylethanoids 9 and 10 increased the expression of interleukin-10 and endothelial nitric oxide synthase. Therefore, compounds 9 and 10 showed anti-inflammatory activity by regulation of NF-
B and JAK/STAT signaling pathways.
Synthetic polyelectrolytes, capable of fast transporting protons, represent a challenging target for membrane engineering in so many fields, for example, fuel cells, redox flow batteries, etc. ...Inspired by the fast advance in molecular machines, here we report a rotaxane based polymer entity assembled via host-guest interaction and prove that by exploiting the thermally triggered translational motion (although not in a controlled manner) of mechanically bonded rotaxane, exceptionally fast proton transfer can be fulfilled at an external thermal input. The relative motion of the sulfonated axle to the ring in rotaxane happens at ~60 °C in our cases and because of that a proton conductivity (indicating proton transfer rate) of 260.2 mS cm
, which is much higher than that in the state-of-the-art Nafion, is obtained at a relatively low ion-exchange capacity (representing the amount of proton transfer groups) of 0.73 mmol g
.
A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), ...polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested.
Display omitted
•Bipolar membranes were prepared through electrospinning followed by post-treatment.•As-prepared membranes were successfully applied in electrodialysis for production of acid and base.•Electrospun membranes exhibit better performance than the casting ones.
Abstract
This paper is concerned with the path-dependent shrinking target problems in beta-dynamical systems. For
β
> 1 let
T
β
be the
β
-transformation on
0
,
1
. Let
1
<
β
1
⩽
β
2
, and
f
,
g
be ...two positive continuous functions. For any
x
0
,
y
0
∈
0
,
1
, we show that the set
E
T
β
1
,
T
β
2
,
f
,
g
=
x
,
y
∈
0
,
1
2
:
|
T
β
1
n
x
−
x
0
|
<
e
−
S
n
β
1
f
x
|
T
β
2
n
y
−
y
0
|
<
e
−
S
n
β
2
g
y
for infinitely many
n
∈
N
has large intersection property under the condition
β
1
e
min
f
(
x
)
≥
β
2
, where
S
n
β
h
(
x
)
denotes the ergodic sum
∑
j
=
0
n
−
1
h
(
T
β
j
x
)
. Consequently, we can determine the Hausdorff dimension of
E
(
T
β
1
,
T
β
2
,
f
,
g
)
, which is the solution to some modified pressure function defined through singular value function.
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