Based on the reported research, hydroxyl radicals can be rapidly transformed into carbonate radicals in the carbonate-bicarbonate buffering system in vivo. Many of the processes considered to be ...initiated by hydroxyl radicals may be caused by carbonate radicals, which indicates that lipid peroxidation initiated by hydroxyl radicals can also be caused by carbonate radicals. To date, theoretical research on reactions of hydrogen abstraction from and radical addition to polyunsaturated fatty acids (PUFAs) of carbonate radicals has not been carried out systematically. This paper employs (3Z,6Z)-nona-3,6-diene (NDE) as a model for polyunsaturated fatty acids (PUFAs). Density functional theory (DFT) with the CAM-B3LYP method at the 6-311+g(d,p) level was used to calculate the differences in reactivity of carbonate radicals abstracting hydrogen from different positions of NDE and their addition to the double bonds of NDE under lipid solvent conditions with a dielectric constant of 4.0 (CPCM model). Grimme's empirical dispersion correction was taken into account through the D3 scheme. The energy barrier, reaction rate constants, internal energy, enthalpy and Gibbs free energy changes in these reactions were calculated With zero-point vibrational energy (ZPVE) corrections. The results indicated that carbonate radicals initiate lipid peroxidation primarily through hydrogen abstraction from diallyl carbon atoms. The reaction of hydrogen abstraction from diallyl carbon atoms exhibits the highest reaction rate, with a reaction rate constant approximately 43-fold greater than the second-ranked hydrogen abstraction from allyl carbon atoms. This process has the lowest energy barrier, internal energy, enthalpy, and Gibbs free energy changes, indicating that it is also the most spontaneous process.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Highly efficient and stable 2D/3D hybrid perovskite solar cells using 2‐thiophenemethylammonium (ThMA) as the spacer cation are successfully demonstrated. It is found that the incorporation of ThMA ...spacer cation into 3D perovskite, which forms a 2D/3D hybrid structure, can effectively induce the crystalline growth and orientation, passivate the trap states, and hinder the ion motion, resulting in improved carrier lifetime and reduced recombination losses. The optimized device exhibits a power conversion efficiency (PCE) of 21.49%, combined with a high VOC of 1.16 V and a notable fill factor (FF) of 81%. More importantly, an encapsulated 2D/3D hybrid perovskite device sustains ≈99% of its initial PCE after 1680 h in the ambient atmosphere, whereas the control 3D perovskite device drops to ≈80% of the original performance. Importantly, the device stability under continuous light soaking (100 mW cm−2) is enhanced significantly for 2D/3D perovskite device in comparison with that of the control device. These results reveal excellent photovoltaic properties and intrinsic stabilities of the 2D/3D hybrid perovskites using ThMA as the spacer cation.
2‐Thiophenemethylammonium spacer cations are successfully embedded into formamidinium iodide (FAI)‐ and methylammonium iodide (MAI)‐based 3D perovskites, and these cations can induce the crystalline growth and orientation of the obtained 2D/3D hybrid perovskite. A champion efficiency of 21.49% is demonstrated for a 2D/3D perovskite device, which is combined with a dramatically improved stability in comparison with that of the control device.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Hydraulic fracturing simulation experiments of shale outcrops were first carried out.•Fracture morphology was observed for the first time by high-energy CT scanning.•The effects of multiple factors ...on fractures propagating in shale play were studied.•CT scanning images were combined with internal fractures photographs for analysis.•Hydraulic fracturing of horizontal well was simulated for shale specimens.
“Stimulated reservoir volume” (SRV) makes it possible for commercial production of shale gas by means of multistage fracturing of horizontal wells. However, the formation mechanism of effective fracture network has not been well understood. The mechanism of fracture propagation in shale with hydraulic fracturing needs to be further explored, in order to realize the control on morphology of fracture network with SRV and increase the single well production of shale gas. In this article, the true triaxial test system was deployed for horizontal well hydraulic fracturing simulation experiments of shale outcrops for the first time. The effects of multiple factors on propagating rules of fractures of horizontal well in shale with SRV were studied, and the fracture morphology of post-fracturing rock cores was observed for the first time by high-energy CT scanning using the large-scale non-destructive testing system based on linear accelerator. The results show that the influence of flow rate (for SRV) on fracture complexity differs when its value falls in different intervals. When the horizontal in situ stress difference is less than 9MPa, the hydraulic fracture easily propagates along the natural fractures, forming a fracture network. In this range, when the stress difference is increased, the appearance of the main hydraulic fracture contributes to interconnecting more natural fractures, forming a relatively more complex fracture system. Under the condition of the same horizontal stress difference, if the coefficient of stress difference Kh>0.25, there is an obvious trend to form single main fracture. The effects of viscosity of fracturing fluid and flow rate on the fracture propagation can be expressed by the parameter q⋅μ. When the order of magnitude of q⋅μ-value is 10−9Nm, it is favorable to the generation of fracture network, but too small or too large values are both harmful. The development and cementing strength of depositional beddings seriously affect the propagating complexity of fracture network with hydraulic fracturing. Refracturing helps to produce some new fractures which are different from the initial ones, and better fracturing effect is achieved. The fracture initiation morphology in perforation fracturing is closely related to the distribution of natural fractures (depositional bedding) around the perforations. If the pressure curve fluctuates significantly, it is indicated that the shale core contains a large number of opened natural fractures or depositional beddings before fracturing, which causes the serious loss of fracturing fluid in the propagation process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including ...anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The present study investigates the interdecadal changes in the relationship between El Niño–Southern Oscillation (ENSO) and midlatitude North Atlantic (MNA) sea surface temperature (SST) with ...northwest China (NWC) winter precipitation (WP) variability and the plausible causes. Results show that ENSO and MNA SST have weak correlations with NWC WP before the mid-1990s, whereas the connections are enhanced sharply afterward, with above (below) normal precipitation occuring when there are positive (negative) ENSO SST and negative (positive) MNASST anomalies (SSTA). Remarkable differences are found in the atmospheric circulations. After the mid-1990s, there is a pronounced Pacific–North American–Eurasian (PNA-EU)-like pattern in the Northern Hemisphere, whereas an Arctic Oscillation–like pattern is found before the mid-1990s. The change in the relationships between NWC WP and SSTs is likely attributable to the enhanced connection between ENSO and MNA SST after the mid-1990s. It is found that ENSO and MNA SSTA can cause NWC WP variation independently through atmospheric teleconnections. In addition, significant precipitation anomalies also occur when concurrent but oppositely signed SSTs anomalies in the two regions are observed. The reinforced negative correlations between ENSO and MNA SST after the mid-1990s act in concert on NWC WP by exciting a PNA-EU-like pattern. This information would help us to better understand the physical processes of the teleconnections between NWC WP variability and the ENSO/MNA SST, in which the strength of the correlation between ENSO and MNA SST should be taken into account.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The rapid expansion of the COVID-19 pandemic has made the development of a SARS-CoV-2 vaccine a global health and economic priority. Taking advantage of versatility and rapid development, three ...SARS-CoV-2 mRNA vaccine candidates have entered clinical trials with a two-dose immunization regimen. However, the waning antibody response in convalescent patients after SARS-CoV-2 infection and the emergence of human re-infection have raised widespread concerns about a possible short duration of SARS-CoV-2 vaccine protection. Here, we developed a nucleoside-modified mRNA vaccine in lipid-encapsulated form that encoded the SARS-CoV-2 RBD, termed as mRNA-RBD. A single immunization of mRNA-RBD elicited both robust neutralizing antibody and cellular responses, and conferred a near-complete protection against wild SARS-CoV-2 infection in the lungs of hACE2 transgenic mice. Noticeably, the high levels of neutralizing antibodies in BALB/c mice induced by mRNA-RBD vaccination were maintained for at least 6.5 months and conferred a long-term notable protection for hACE2 transgenic mice against SARS-CoV-2 infection in a sera transfer study. These data demonstrated that a single dose of mRNA-RBD provided long-term protection against SARS-CoV-2 challenge.
The lithium/fluorinated carbon (Li/CF
x
) battery is a widely used solid-state lithium primary battery (LPB) with the highest ever known specific energy. However, the scarcity of lithium resources ...compels researchers to explore other types of batteries. Sodium batteries have been considered as the most suitable candidate power sources due to the low cost of sodium and its similar chemistry to lithium. In this work, we prepared two series of fluorinated carbon nanotubes (CNTs), which are fluorinated common CNTs (FCNT-
x
) and fluorinated graphitized CNTs (FGCNT-
x
). The effects of graphitization of the CNTs on the structure of fluorinated carbon nanotubes and C–F bonding are systematically studied. FGCNT-
x
prepared from the graphitized CNTs exhibit a lower ratio of F/C and weaker C–F bonding than those of the FCNT-
x
prepared from ordinary CNTs at the same fluorination temperature. FGCNT-0.81 exhibits very high specific capacities of 798.8 and 751 mA h g
−1
in lithium and sodium primary batteries, nearly reaching the theoretical capacity calculated using the F/C ratio. Besides, FGCNT-0.81 possesses a maximum energy density of 2006.6 W h kg
−1
in Li/CF
x
batteries and 1733.4 W h kg
−1
in Na/CF
x
batteries. The maximum power density for Li/CF
x
and Na/CF
x
batteries could reach up to 3861.1 (FCNT-0.81) and 1863.9 W h kg
−1
(FGCNT-0.81), respectively. It is proved that the binding energy of the C–F bond, the electronegativity and the polarization force of the metal ions collaboratively determine the electrochemical performance of the fluorinated CNTs. The new-type Na/CF
x
primary batteries developed here are promising in low power applications such as high-energy density and low-cost batteries.
The dominant modes wintertime precipitation in northwest China (NWC) and the possible causes are investigated during the period 1961–2013 in the inter‐annual timescale, as winter climate condition ...could greatly affect local economic development and people's lives. The analysis of this study is divided into three parts. First, the spatiotemporal variability of dominant modes wintertime precipitation is described by an empirical orthogonal function (EOF) method. The atmospheric circulation anomalies associated with wintertime precipitation variations are then discussed through regression and composite analysis. Third, the relationships between wintertime precipitation and sea surface temperature (SST) anomalies are investigated. The results indicate that the leading mode (EOF1) shows a uniform sign in the entire region, and the second mode (EOF2) exhibits a zonal‐dipole pattern; they account for 25.6 and 15.7% of the total variance, respectively. The atmospheric circulation anomalies EOF1 closely related to is the Eurasian (EU) teleconnection pattern. Years when a negative phase of EU pattern occurs tend to be rainy with anomalous southerly transporting water vapour from low‐latitudes and profound ascending motion anomalies. Atmospheric circulation anomalies associated with the second mode resemble the Arctic Oscillation (AO) pattern. AO pattern influences EOF2 precipitation variations through the anomalous circulations over Mongolia and western Europe. The sea surface temperature (SST) anomalies related to EOF1 show an El Niño‐Southern Oscillation (ENSO) like pattern, which may modulate the wintertime precipitation mode through the western North Pacific anticyclone. The EOF2 mode has a close relationship with a tripole SST anomaly mode in the North Atlantic Ocean. This SST pattern is likely to influence wintertime precipitation by modulating the North Atlantic Oscillation (NAO). The results of this study could be beneficial for wintertime precipitation prediction and the decrease of economic losses in NWC and may also provide useful references for other areas with similar climatic features such as the central Asia.
(a, c) EOF1 and (b, d) EOF2 of inter‐annual wintertime precipitation variations for 1961–2013 in NWC. (a, b) Regression maps on the normalized time series (unit: mm); (c, d) normalized time series.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Some necessary and sufficient conditions are derived for the stability of a networked system with linear time invariant dynamics. Connections among its subsystems are fixed but arbitrary, and every ...subsystem can have different dynamics. Based on these results, some necessary or sufficient conditions are further obtained for both its stability and robust stability, which essentially depend only on parameter matrices of each individual subsystem and the subsystem connection matrix. This characteristic makes them attractive in the analysis and synthesis of a large scale networked system.
This letter investigates the minimal number of inputs/outputs required to guarantee system controllability/observability, under the condition that its state transition matrix (STM) is prescribed. A ...closed-form solution is derived. It has been proven that this minimal number is equal to the maximum geometric multiplicity of the STM, that is, the maximum of the dimensions of its eigenspaces. The obtained conclusions are in sharp contrast to those established for the problem of finding the sparest input/output matrix with a fixed number of inputs/outputs under the same restrictions. The latter has been proven to be NP-hard, and can only be approximated within a multiplicative factor. Moreover, a complete parametrization is also provided for the input/output matrix of a system with its number of inputs/outputs not smaller than this minimal value.
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