Improving the electrochemical reaction kinetics is of great importance but remains challenging for the applications of hydroxide materials in the field of energy conversion and storage. Through ...rational nanostructure design with modified compositions, herein, a hierarchical scale-like trimetallic hydroxide (CuCoNi-OH) array is synthesized using a novel bimetallic 2D-zeolitic imidazolate framework (CuCo-ZIF-L) as structure-inducing template under a moderate alkaline hydrolysis strategy. The hierarchical and porous structure offers large exposure of active sites and rapid electrolyte diffusion, and the multi-metallic synergistic effect provides high electrical conductivity and fast redox transformation, both promoting the electrochemical reaction kinetics of supercapacitor and oxygen evolution reaction (OER). When evaluated as a battery-type electrode, the CuCoNi-OH electrode delivers a high specific capacity of 821.6 C g-1 at 1 A g-1 with capacity retention of 89.8% at 20 A g-1, and the assembled hybrid supercapacitor exhibits high energy density and power density. Moreover, the CuCoNi-OH electrode also shows competitive OER activity with a low overpotential of 290 mV at 10 mA cm-2. This strategy demonstrates its universality in the fabrication of bimetallic ZIF-L and corresponding metallic hydroxides, and opens a new approach for the rational design of high-performance materials for electrochemical energy storage and conversion applications.
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•Hierarchical CuCoNi-OH array was synthesized using a new bimetallic 2D-ZIF.•This CuCoNi-OH electrode delivers excellent capacity and catalytic performance.•The structure regulation and Cu doping enhance the electrochemical reaction kinetics.•This general strategy is versatile for other application and fabrication.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sleep loss and its associated conditions (e.g. cognitive deficits) represent a large societal burden, but the underlying mechanisms of these cognitive deficits remain unknown. This study assessed the ...effect of dexmedetomidine (DEX) on cognitive decline induced by sleep loss.
C57BL/6 mice were subjected to chronic sleep restriction (CSR) for 20 h (5 pm–1 pm the next day) daily for 7 days, and cognitive tests were subsequently carried out. The neuromolecular and cellular changes that occurred in the presence and absence of DEX (100 μg kg−1, i.v., at 1 pm and 3 pm every day) were also investigated.
CSR mice displayed a decline in learning and memory by 12% (P<0.05) in the Y-maze and by 18% (P<0.01) in the novel object recognition test; these changes were associated with increases in microglial activation, CD68+ microglial phagosome counts, astrocyte-derived complement C3 secretion, and microglial C3a receptor expression (all P<0.05). Synapse elimination, as indicated by a 66% decrease in synaptophysin expression (P=0.0004) and a 45% decrease in postsynaptic density protein-95 expression (P=0.0003), was associated with the occurrence of cognitive deficits. DEX activated astrocytic α2A adrenoceptors and inhibited astrocytic complement C3 release to attenuate synapse elimination through microglial phagocytosis. DEX restored synaptic connections and reversed cognitive deficits induced by CSR.
The results demonstrate that complement pathway activation associated with synapse elimination contributes to sleep loss-related cognitive deficits and that dexmedetomidine protects against sleep deprivation-induced complement activation. Dexmedetomidine holds potential for preventing cognitive deficits associated with sleep loss, which warrants further study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
BACKGROUND: Measurement of red blood cell (RBC) survival (RCS) is important for investigating pathophysiology and treatment of anemia. Our objective was to validate the multidensity biotin method for ...RCS determination in sheep, a commonly used model of RBC physiology. 14CCyanate served as the reference method for long‐term RCS because the 51Cr method (the reference method for humans) is not reliable in sheep.
STUDY DESIGN AND METHODS: Aliquots of autologous RBCs from eight adult sheep were labeled with 14Ccyanate and four separate densities of biotin (BioRBCs) and reinfused. Short‐term RCS was assessed by posttransfusion recovery at 24 hours (PTR24); long‐term RCS was assessed by the time to 50% survival (T50) and mean potential life span (MPL).
RESULTS: Values for PTR24 of the four BioRBC densities were not different. Values for RCS as reflected by T50 and MPL were nearly identical for 14Ccyanate and the two intermediate‐density BioRBC populations. In contrast, the lowest‐density BioRBC population survived slightly longer (p < 0.01), but with a difference of no clinical significance. The highest‐density BioRBC population importantly shortened RCS (p < 0.01 compared to the two intermediate densities).
CONCLUSION: This study provides evidence that BioRBCs labeled at four biotin densities can be used to independently and simultaneously measure short‐term RCS and that BioRBCs labeled at the three lowest biotin densities can be used to accurately and simultaneously measure long‐term RCS. Because the sheep RBC model is comparable to humans, this nonradioactive method has promise for use in RBC kinetic studies in neonates and pregnant women.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this work, a micromixing module was utilized in the polymerization of isobutylene (IB) initiated by
tert
-butyl chloride (
t
-BuCl) and catalyzed by ethylaluminum dichloride ...(EADC)/bis(2-chloroethyl)ether (CEE) complex for the synthesis of highly reactive polyisobutylene (HRPIB). Better micromixing performance resulted in HRPIB with narrower molecular weight distribution, where the PDI could be decreased from 3.5 without micromixing module to 2.5 or less. The polymerization rate also increased while the molecular weight and content of
exo
-olefin end groups of HRPIBs could be adjusted conveniently by the ratio of CEE to EADC and monomer concentration. A dynamic mechanism was proposed to explain the effects of micromixing on the enhanced HRPIB synthesis.
Better mixing could produce more active centers to accelerate the polymerization by promoting the consumption of carbonium ions.
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•Small-size carbon-coated Pt-Co alloy catalysts were successfully synthesized.•High-pressure nitrogen can inhibit nanoparticle growth during annealing.•Carbon-shell can hinder alloy particle ...agglomeration and metal dissolution.
The development of small-sized platinum-based alloy catalysts with exceptional stability is crucial for the advancement of oxygen reduction reactions in fuel cells. Herein, we present a synthesis approach for fabricating small-sized carbon-encapsulated PtCo/C catalysts facilitated by high-pressure nitrogen during annealing. Remarkably, the resulting PtCo/C catalyst exhibits outstanding performance, showcasing minimal degradation (4.7%) in mass activity after enduring 30,000 cycles owing to its robust carbon-coating architecture.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
S-Adenosyl-
l-methionine (SAM) was accumulated by high cell-density culture with
Pichia pastoris overexpressing methionine adenosyltransferase (MAT). To enhance enzymatic synthesis of SAM during the ...biotransformation phase, a novel feeding strategy different to classical mode with sole methanol feeding was developed. The typical induction phase was divided into ten 10
h subintervals, during which alternate feedings of methanol (first 6
h) and glycerol (later 4
h) were employed. Compared to the standard fermentation protocol, the intermittent addition of glycerol improved growth rate and volumetric activity of intracellular MAT. Remarkably, no acute fluctuation of enzyme activity occurred during intervals absent of inducible methanol feeding. However, the specific MAT activity was depressed versus that with classical strategy prior to cells decomposition. It should be noted that even if the specific enzyme activity was lower, the synthesis rate of SAM was still enhanced, which led to a higher accumulation rate of net product. The main reason was that total ATP generation was enriched every time when carbon source feeding was switched from inducible methanol to non-inducible glycerol. The success in fermentation performance with the novel feeding scheme could also be attributed to a longer production period (from induction to harvest), in addition to a higher SAM accumulation speed. The final product concentration, specific yield of SAM and conversion efficiency of supplementary
l-methionine obtained were elevated at 13.24
g/l, 0.055
g/g and 32.97%, respectively, as compared with that of 9.86
g/l, 0.046
g/g and 24.55% with the standard protocol, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Summary Background Closure of donor-site defects from large cutaneous flap harvesting often faces significant morbidity, which limits the utility of workhorse flaps in large-soft-tissue defect ...reconstruction. To overcome this limitation, we introduced the concept of a second ‘buddy’ flap to reconstruct the donor-site defect. Methods Between 2007 and 2010, the buddy flap concept was applied in 12 patients. In each case, the primary flap, which included the latissimus dorsi myocutaneous flap, parascapular flap, transverse rectus abdominis myocutaneous flap, superficial inferior epigastric artery flap and anterolateral thigh flap, was transferred to repair the primary defect. In addition, a secondary pedicle flap, either an axial flap or a perforator flap, was chosen as a buddy flap for closure of the donor-site defect. Results The primary defects ranged from 10 × 7 to 35 × 20 cm in size. Donor-site closure was accomplished using buddy flaps with preserved normal contour and acceptable scars. Additional time for the buddy flap harvesting and insetting was within 1 h. All flaps survived completely. There were three cases with complications, such as seroma, wound infection and haematoma, which were managed accordingly without compromising the viability of flaps. Conclusions The buddy flap approach achieved reliable coverage of large donor-site defects with low morbidity and excellent aesthetic results. This technique allows reconstructive surgeons to harvest large cutaneous flaps without being limited by significant donor-site morbidity. We demonstrate that this technique can diminish the concern regarding donor-site defect in large soft-tissue reconstruction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The onset of distal metastasis, which underlies the high mortality of breast cancers, warrants substantial studies to depict its molecular basis. Nuclear factor of activated T cells 5 (NFAT5) is ...upregulated in various malignancies and is critically involved in migration and invasion of neoplastic cells. Nevertheless, the metastasis-related events potentiated by this transcriptional factor and the mechanism responsible for NFAT5 elevation in carcinoma cells remain to be fully elucidated.
The correlation of NFAT5 with breast cancer invasiveness was investigated in vitro and clinically. The genes transcriptionally activated by NFAT5 were probed and their roles in breast cancer progression were dissected. The upstream regulators of NFAT5 were studied with particular attempt to explore the involvement of non-coding RNAs, and the mechanism underlying the maintenance of NFAT5 expression was deciphered.
In metastatic breast cancers, NFAT5 promotes epithelial-mesenchymal transition (EMT) and invasion of cells by switching on the expression of the calcium binding protein S100A4, and facilitates the angiogenesis of breast epithelial cells and thus the development of metastases by transcriptionally activating vascular endothelial growth factor C (VEGF-C). NFAT5 is directly targeted by miR-568, which is in turn suppressed by the long non-coding RNA, Hotair, via a documented in trans gene silencing pattern, that is recruitment of the polycomb complex (Polycomb Repressive Complex 2; PRC2) and LSD1, and consequently methylation of histone H3K27 and demethylation of H3K4 on the miR-568 loci.
This study unravels a detailed role of NFAT5 in mediating metastatic signaling, and provides broad insights into the involvement of Hotair, in particular, by transcriptionally regulating the expression of microRNA(s), in the metastasis of breast cancers.
This paper reports the flow synthesis of highly reactive polyisobutylenes (HRPIBs) in pure
-hexane using properly prepared AlCl
·Et
O crystals in conjunction with AlCl
·iPr
O solution as ...coinitiators. By preparing AlCl
·iPr
O solution and AlCl
·Et
O crystals separately, the cationic polymerization of isobutylene proceeded smoothly under a wide range of monomer concentrations (0.33-1.30 M) in the presence of H
O as an initiator, affording a high yield (∼89%) and a moderate exo-olefin terminal group content (60-75%) in 10 min. The various functions of iPr
O and Et
O in the initiator solution were comprehensively revealed from the polymerization results, attenuated total reflection-Fourier transform infrared and
Al nuclear magnetic resonance spectra, and density functional theory simulations. AlCl
·iPr
O was confirmed to be the key component that stabilized carbenium ions. The AlCl
·Et
O complex was the key component to promote proton elimination. Free Et
O should be removed to inhibit its negative effect on isomerization. This new strategy may lead to high commercial interest in HRPIB synthesis in pure green solvent and could potentially be extended to other initiation systems containing solid Lewis acids.
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IJS, KILJ, NUK, UL, UM, UPUK
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