Harnessing mitochondria is considered as a promising method for biosynthesis of terpenes due to the adequate supply of acetyl-CoA and redox equivalents in mitochondria. However, mitochondrial ...engineering often causes serious metabolic burden indicated by poor cell growth. Here, we systematically analyzed the metabolic burden caused by the compartmentalization of the MVA pathway in yeast mitochondria for squalene synthesis. The phosphorylated intermediates of the MVA pathway, especially mevalonate-5-P and mevalonate-5-PP, conferred serious toxicity within mitochondria, which significantly compromised its possible advantages for squalene synthesis and was difficult to be significantly improved by routine pathway optimization. These phosphorylated intermediates were converted into ATP analogues, which strongly inhibited ATP-related cell function, such as mitochondrial oxidative respiration. Fortunately, the introduction of a partial MVA pathway from acetyl-CoA to mevalonate in mitochondria as well as the augmentation of the synthesis of mevalonate in cytosol could significantly promote the growth of yeasts. Accordingly, a combinatorial strategy of cytoplasmic and mitochondrial engineering was proposed to alleviate the metabolic burden caused by the compartmentalized MVA pathway in mitochondria and improve cell growth. The strategy also displayed the superimposed effect of cytoplasmic engineering and mitochondrial engineering on squalene production. Through a two-stage fermentation process, the squalene titer reached 21.1 g/L with a specific squalene titer of 437.1 mg/g dcw, which was the highest at present. This provides new insight into the production of squalene and other terpenes in yeasts based on the advantages of mitochondrial engineering.
•Compartmentalizing the MVA pathway in yeast mitochondria can cause serious metabolic burden.•The phosphorylated metabolites of the MVA pathway are toxic within mitochondria.•Enhanced synthesis of mevalonate in cytosol can conquer the burden of mitochondrial engineering.•Cytoplasmic engineering is needed to take the full advantage of mitochondrial engineering.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In order to realize the innovation of sports teaching mode, this paper first combines the motion capture technology and three-dimensional modeling technology, based on the objectives and theories of ...sports teaching in colleges and universities, and constructs a college sports auxiliary teaching system under the fusion network architecture. Then, the three-dimensional modeling of sports action, the extraction of key sports action features, and the use of generalized discriminant analysis and hierarchical SVM construction method for the degradation and classification, respectively, to achieve the recognition of the sport in sports teaching. Finally, the effectiveness of the system and teaching model was tested and evaluated through the use of Loadrunner and SPSS software. The results show that the response time is 2s when the number of concurrent users is 100, the utilization rate of CPU is 64.2%, and the mastery of sports knowledge and movement skills of the experimental class is higher than that of the control class by 0.18 and 0.26, respectively. The innovative teaching mode of physical education in this study is effective.
In this article, the analyticity of triangle loop integral with complex masses of internal particles is discussed in a new perspective, based on which we obtain the explicit width dependence of the ...absorptive part of the triangle amplitude. We reanalyze the decay pattern of η(1405/1475) with the width effects included in the triangle singularity (TS) mechanism. Based on the present experimental information, we provide a self-consistent description of the KK¯π, ηππ, and 3π decay channels for η(1405/1475). Our results confirm the claim that the TS mechanism plays a decisive role in the understanding of the η(1405) and η(1475) puzzle. Namely, the observed differences of η resonances within the mass region of 1.40–1.48 GeV are originated from the same state. For the isospin violated process J/ψ→γη(1405/1475)→f0(980)π→3π, we identify an additional contribution to the a0(980)−f0(980) mixing via the TS mechanism.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
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•A review based on metal-organic framework films and their composites.•Synthetic strategies and applications are studied.•Challenges in future development of metal-organic framework ...films are addressed.
Metal-organic frameworks (MOFs) are crystalline porous materials in which metal ions or clusters are constructed in cooperation with organic linkers. MOFs have received tremendous attention in the fields of both inorganic and organic chemistry owing to their high porosity, large specific surface area, regular pore arrangement, and adjustable pore size. This article reviews a large number of preparation methods for MOF films, including liquid phase epitaxy, supersonic cold spraying, direct gas-phase preparation, and interface-assisted synthesis. Thereafter, we introduce applications of MOF films in the fields of optics, sensing, catalysis, adsorption, and separation, as well as their electrochemical energy storage. At the end of this review, we describe the challenges that need to be overcome and consider future perspectives for synthesis and applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The photoproduction of the
J
/
ψ
off the proton is believed to deepen our understanding of various physics issues. On the one hand, it is proposed to provide access to the origin of the proton mass, ...based on the QCD multipole expansion. On the other hand, it can be employed in a study of pentaquark states. The process is usually assumed to proceed through vector-meson dominance, that is the photon couples to a
J
/
ψ
which rescatters with the proton to give the
J
/
ψ
p
final state. In this paper, we provide a compelling hint for and propose measurements necessary to confirm a novel production mechanism via the
Λ
c
D
¯
(
∗
)
intermediate states. In particular, there must be cusp structures at the
Λ
c
D
¯
(
∗
)
thresholds in the energy dependence of the
J
/
ψ
photoproduction cross section. The same mechanism also implies the
J
/
ψ
-nucleon scattering lengths of order 1 mfm. Given this, one expects only a minor contribution of charm quarks to the nucleon mass.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•The Ni/NiO sample was prepared by calcination of nickel oxalate precursor.•The Ni(0) content was adjusted by varying the pyrolysis temperature.•The porous structure facilitates ...electrolyte infiltration and fast ion transport.•The presence of Ni in Ni/NiO nanocomposites improves electrical conductivity.
NiO is a highly appealing anode material for lithium-ion batteries (LIBs) owing to its relatively high Li storage capacity. However, its low electrical conductivity and large volume change during the battery cycling process limit its application. Here, we fabricate a series of porous Ni/NiO (M) nanocomposites through the direct pyrolysis of a nickel oxalate precursor and adjust the Ni(0) content by varying the pyrolysis temperature. The porous architecture is beneficial for alleviating the volume expansion/constriction during cycling. The Ni in the composites accelerates the electrochemical reaction kinetics and enhances the conductivity of the electrode materials. The M-2 electrode with a 17.9% Ni(0) content realizes a high reversible capacity (633.7 mA h g−1 after 100 cycles at 0.2 A g−1) and exhibits outstanding rate capability (307.6 mA h g−1 after 250 cycles at 1 A g−1). This work can not only supply an approach to adjust the content of an element with specific valence state, but also provide an inspiration for the fabrication of porous metal/metal oxide anode materials in LIBs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, the kinetics study on the reaction between CO2 and tertiary amine catalyzed by zinc(II)‐1,4,8,11‐tetraazacyclotetradecane complexes (CM) and zinc(II)‐1,4,7,10‐tetraazacyclododecane ...complexes (CN) was carried out in a stopped‐flow device. The effects of the catalyst concentration, type of tertiary amines, and temperature on the reaction rate (ν) and catalytic activity (φ) were studied. It was found that the catalyst concentration, tertiary amine with higher pKa, and temperature had positive effects on ν. ν in N‐methyl diethanolamine solution with 10.0 mol m−3 CM and CN were 16.62 and 26.05 folds than the uncatalyzed ν at 298 K, respectively. φ increased with increasing catalyst concentration, decreasing temperature and tertiary amine's pKa. In addition, the kinetics behavior of tertiary amine‐CM/CN‐CO2 systems conformed to the Michaelis–Menten model. The activation energies in catalytic systems were 4%–15% lower than that in the non‐catalytic systems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We show that the Pomeron exchanges play a unique role in vector charmonium scatterings. Such a mechanism can provide a natural explanation for the nontrivial structures in the di-J/ψ spectrum ...observed by the LHCb Collaboration. The narrow structure X(6900), as a dynamically generated resonance pole, can arise from the Pomeron exchanges and coupled-channel effects between the J/ψ-J/ψ, J/ψ-ψ(2S) scatterings. A pole structure near the di-J/ψ threshold is also found. Meanwhile, we predict that X(6900) can produce significant threshold enhancement in the J/ψ-ψ(2S) energy spectrum which can be searched for at LHCb.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Bacteria-based tumor therapy has recently attracted wide attentions due to its unique capability in targeting tumors and preferentially colonizing the core area of the tumor. Various therapeutic ...genes are also harbored into these engineering bacteria to enhance their anti-tumor efficacy. However, it is difficult to spatiotemporally control the expression of these inserted genes in the tumor site. Here, we engineer an ultrasound-responsive bacterium (URB) which can induce the expression of exogenous genes in an ultrasound-controllable manner. Owing to the advantage of ultrasound in tissue penetration, an acoustic remote control of bacterial gene expression can be realized by designing a temperature-actuated genetic switch. Cytokine interferon-γ (IFN-γ), an important immune regulatory molecule that plays a significant role in tumor immunotherapy, is used to test the system. Our results show that brief hyperthermia induced by focused ultrasound promotes the expression of IFN-γ gene, improving anti-tumor efficacy of URB in vitro and in vivo. Our study provides an alternative strategy for bacteria-mediated tumor immunotherapy.
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