Abstract
Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energy-saving hydrogen production from the biomass-based platform molecules. Here we report that ...nanostructured NiFe oxide (NiFeO
x
) and nitride (NiFeN
x
) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm
−2
at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H
2
production and biomass valorization.
In this paper, we develop the theory of basic reproduction ratios
R
0
for abstract functional differential systems in a time-periodic environment. It is proved that
R
0
-
1
has the same sign as the ...exponential growth bound of an associated linear system. Then we apply it to a time-periodic Lyme disease model with time-delay and obtain a threshold type result on its global dynamics in terms of
R
0
.
In this paper, we establish the theory of basic reproduction ratio
R
0
for a large class of time-delayed compartmental population models in a periodic environment. It is proved that
R
0
serves as a ...threshold value for the stability of the zero solution of the associated periodic linear systems. As an illustrative example, we also apply the developed theory to a periodic SEIR model with an incubation period and obtain a threshold result on its global dynamics in terms of
R
0
.
We study a Lotka–Volterra type reaction–diffusion–advection system, which describes the competition for the same resources between two aquatic species undergoing different dispersal strategies, as ...reflected by their diffusion and/or advection rates. For the non-advective case, this problem was solved by Dockery et al. 9, and recently He and Ni 14 provided a further classification on the global dynamics for a more general model. However, the key ideas developed in 9,14 do not appear to work when advection terms are involved. By assuming the resource function is decreasing in the spatial variable, we establish the non-existence of co-existence steady state and perform sufficient analysis on the local stability of two semi-trivial steady states, where new techniques were introduced to overcome the difficulty caused by the non-analyticity of stationary solutions as well as the diffusion–advection type operators. Combining these two aspects with the theory of monotone dynamical systems, we finally obtain the global dynamics, which suggests that the competitive exclusion principle holds in most situations.
Nous étudions un systéme de réaction-diffusion-advection de type Lotka-Volterra, qui décrit la compétition pour les mêmes ressources entre deux espéces aquatiques ayant différentes stratégies de dispersion, reflétées par leurs taux de diffusion et/ou d'advection. Le cas sans advection a été traité par Dockery et al. 9, et récemment He et Ni 14 ont également donné une classification de la dynamique globale pour un modéle plus général. Cependant, les idées clés développées dans 9,14 ne semblent pas fonctionner en présence de termes d'advection. En supposant que les ressources sont décroissantes par rapport á la variable d'espace, nous montrons la non-existence d'état stationnaire avec co-existence des espéces et analysons la stabilité locale de deux états stationnaires semi-triviaux. De nouvelles techniques sont introduites pour contourner la difficulté créée par la non-analyticité des solutions stationnaires et par des opérateurs de type diffusion-advection. En combinant ces deux aspects avec la théorie des systémes dynamiques monotones, nous obtenons finalement la dynamique globale, qui suggére que le principe d'exclusion par compétition se produit dans la plupart des situations.
In this paper, we propose a time-periodic reaction–diffusion model which incorporates seasonality, spatial heterogeneity and the extrinsic incubation period (EIP) of the parasite. The basic ...reproduction number
R
0
is derived, and it is shown that the disease-free periodic solution is globally attractive if
R
0
<
1
, while there is an endemic periodic solution and the disease is uniformly persistent if
R
0
>
1
. Numerical simulations indicate that prolonging the EIP may be helpful in the disease control, while spatial heterogeneity of the disease transmission coefficient may increase the disease burden.
The basic reproduction ratio and its computation formulae are established for a large class of compartmental epidemic models in periodic environments. It is proved that a disease cannot invade the ...disease-free state if the ratio is less than unity and can invade if it is greater than unity. It is also shown that the basic reproduction number of the time-averaged autonomous system is applicable in the case where both the matrix of new infection rate and the matrix of transition and dissipation within infectious compartments are diagonal, but it may underestimate and overestimate infection risks in other cases. The global dynamics of a periodic epidemic model with patch structure is analyzed in order to study the impact of periodic contacts or periodic migrations on the disease transmission.
Compared with the popularity of various C-centred radicals, the N-centred radicals remain largely unexplored in catalytic radical cascade reactions because of a lack of convenient methods for their ...generation. Known methods for their generation typically require the use of N-functionalized precursors or various toxic, potentially explosive or unstable radical initiators. Recently, visible-light photocatalysis has emerged as an attractive tool for the catalytic formation of N-centred radicals, but the pre-incorporation of a photolabile groups at the nitrogen atom largely limited the reaction scope. Here, we present a visible-light photocatalytic oxidative deprotonation electron transfer/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediation strategy for catalytic N-radical cascade reaction of unsaturated hydrazones. This mild protocol provides a broadly applicable synthesis of 1,6-dihydropyradazines with complete regioselectivity and good yields. The 1,6-dihydropyradazines can be easily transformed into diazinium salts that showed promising in vitro antifungal activities against fungal pathogens. DFT calculations are conducted to explain the mechanism.
Efficient recruitment and angiogenesis of endothelial progenitor cells (EPCs) are critical during a thrombus event. However, the details of EPC recruitment and the regulation of angiogenesis have not ...been fully determined. The aim of this study was to determine the role of the long noncoding (lnc)RNA Wilms tumor 1 associated protein pseudogene 1 (WTAPP1) in regulation of the migration and angiogenesis of EPCs. EPCs were isolated from human peripheral blood and characterized by flow cytometry, after which lentivirus‐mediated lncRNA WTAPP1 overexpression and knockdown were performed. Scratch assay, Transwell assay, and in vitro and in vivo tube formation assays were performed to measure cell migration, invasion, and angiogenic abilities, respectively. Moreover, a microarray screen, bioinformatic prediction, and quantitative PCR and Western blot of miRNAs interacting with lncRNA WTAPP1 were conducted. Western blot was carried out to elucidate the relationship among WTAPP1, miR‐3120‐5P, and MMP‐1 in the autophagy pathway. WTAPP1 positively regulated migration, invasion, and in vitro and in vivo tube formation in EPCs by increasing MMP‐1 expression and activating PI3K/Akt/mTOR signaling. Furthermore, WTAPP1 contains a putative miR‐3120‐5P binding site. Suppression of WTAPP1 by miR‐3120‐5P decreased the level of MMP‐1. In addition, we demonstrated that suppression of the autophagy pathway is involved in the effects of WTAPP1 on EPC migration and angiogenesis. The lncRNA WTAPP1, a molecular decoy for miR‐3120‐5p, regulates MMP‐1 expression via the PI3K/Akt and autophagy pathways, thereby mediating cell migration and angiogenesis in EPCs. Acting as a potential therapeutic target, the lncRNA WTAPP1 may play an important role in the pathogenesis of DVT. Stem Cells 2018;36:1863–12
The long noncoding RNA Wilms tumor 1 associated protein pseudogene 1, a molecular decoy for miR‐3120‐5p, regulates MMP‐1 expression via the PI3K/Akt and autophagy pathways, thereby mediating cell migration and angiogenesis in endothelial progenitor cells.
In this paper, we propose a periodic reaction–diffusion model of Zika virus with seasonal and spatial heterogeneous structure in host and vector population. We introduce the basic reproduction ratio
...R
0
for this model and show that the disease-free periodic solution is globally asymptotically stable if
R
0
≤
1
, while the system admits a globally asymptotically stable positive periodic solution if
R
0
>
1
. Numerically, we study the Zika transmission in Rio de Janeiro Municipality, Brazil, and investigate the effects of some model parameters on
R
0
. We find that the neglect of seasonality underestimates the value of
R
0
and the maximum carrying capacity affects the spread of Zika virus.
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