Supported metal oxide nanoparticles are important in heterogeneous catalysis; however, the ability to tailor their size, structure, and dispersion remains a challenge. A strategy to achieve ...well‐dispersed and size‐controlled supported metal oxides through the manageable growth of a metal organic framework (Cu–BTC) on TiO2 followed by pyrolysis is described.
The α2δ subunit is a high-voltage activated (HVA) calcium channel (Cav1 and Cav2) auxiliary subunit that increases the density and function of HVA calcium channels in the plasma membrane of mammals. ...However, its function in plant parasitic nematodes remains unknown. In this study, we cloned the full-length cDNA sequence of the voltage-gated calcium channel (VGCC) α2δ subunit (named DdCavα2δ) in Ditylenchus destructor. We found that DdCavα2δ tends to be expressed in the egg stage, followed by the J3 stage. RNA-DIG in situ hybridization experiments showed that the DdCavα2δ subunit was expressed in the body wall, esophageal gland, uterus, post uterine, and spicules of D. destructor. The in vitro application of RNA interference (RNAi) affected the motility, reproduction, chemotaxis, stylet thrusting, and protein secretion of D. destructor to different degrees by targeting DdCα1D, DdCα1A, and DdCavα2δ in J3 stages, respectively. Based on the results of RNAi experiments, it was hypothesized that L-type VGCC may affect the motility, chemotaxis, and stylet thrusting of D. destructor. Non-L-type VGCC may affect the protein secretion and reproduction of D. destructor. The DdCavα2δ subunit gene also affected the motility, chemotaxis, and reproduction of D. destructor. These findings reveal the independent function of the VGCC α2δ subunit in D. destructor as well as give a theoretical foundation for future research on plant parasitic nematode VGCC.
Plant-parasitic nematodes (PPNs) cause serious damage to agricultural production worldwide. Currently, because of a lack of effective and environmental-friendly chemical nematicides, the use of ...microbial nematicides has been proposed as an eco-friendly management strategy to control PPNs. A nematicidal bacterium GC-7 was originally isolated from the rice rhizosphere, and was identified as
Pseudomonas rhodesiae.
Treatment with the fermentation supernatant of GC-7
in vitro
showed a highly lethal effect on second-stage juveniles of
Meloidogyne graminicola
, with the mortality rate increasing to 95.82% at 24 h and egg hatching significantly inhibited, with a hatch inhibition rate of 60.65% at 96 h. The bacterium significantly reduced the level of damage caused by
M. graminicola
infestations to rice (
Oryza sativa
) in greenhouse and field experiments. Under greenhouse conditions, the GC-7 culture efficiently reduced the gall index and nematode population in rice roots and soils, as well as inhibited nematode development compared to the control. Under field conditions, application of the GC-7 consistently showed a high biocontrol efficacy against
M. graminicola
(with a control efficiency of 58.85%) and promoted plant growth. In addition, the inoculation of GC-7 in
M. graminicola
-infested rice plant fields significantly suppressed final nematode populations in soil under natural conditions. Furthermore, activities of plant defense-related enzymes, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase were remarkably increased in plant roots treated with GC-7 compared with roots that were challenge to
M. graminicola
. Moreover, quantitative real-time PCR analysis showed that GC-7 significantly enhanced the expression of defense genes (
PR1a
,
WRKY45
,
JaMYB
,
AOS2
,
ERF1
, and
ACS1
) related to salicylic acid, jasmonic acid, and ethylene signaling pathways in rice roots after inoculation with GC-7 at different levels. The results indicated that GC-7 could be an effective biological component in the integrated management of
M. graminicola
infecting rice.
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The development of novel absorbents is essential for SO2 removal. In this study, a novel ionic liquid (IL, BHEPHSO4) was prepared, and water was selected as the co-solvent. The ...density and viscosity of aqueous BHEPHSO4 were measured and the SO2 absorption performance was systematically investigated. Furthermore, the thermodynamic properties of SO2 in aqueous BHEPHSO4 were calculated. Additionally, the mechanism of SO2 absorption in aqueous BHEPHSO4 was confirmed using Fourier-transform infrared and nuclear magnetic resonance spectroscopy. It showed that BHEPHSO4 absorbed 0.302 g⋅g−1 (g SO2/g IL) at an SO2 partial pressure of 2000 μl⋅L−1 at 303.2 K, and the SO2 desorption enthalpy was −39.63 kJ⋅mol−1. The mechanistic study confirmed the chemical absorption of SO2 in aqueous BHEPHSO4.
The voltage-gated calcium channel (VGCC) β subunit (Cavβ) protein is a kind of cytosolic auxiliary subunit that plays an important role in regulating the surface expression and gating characteristics ...of high-voltage-activated (HVA) calcium channels. Ditylenchus destructor is an important plant-parasitic nematode. In the present study, the putative Cavβ subunit gene of D. destructor, namely, DdCavβ, was subjected to molecular characterization. In situ hybridization assays showed that DdCavβ was expressed in all nematode tissues. Transcriptional analyses showed that DdCavβ was expressed during each developmental stage of D. destructor, and the highest expression level was recorded in the third-stage juveniles. The crucial role of DdCavβ was verified by dsRNA soaking-mediated RNA interference (RNAi). Silencing of DdCavβ or HVA Cavα1 alone and co-silencing of the DdCavβ and HVA Cavα1 genes resulted in defective locomotion, stylet thrusting, chemotaxis, protein secretion and reproduction in D. destructor. Co-silencing of the HVA Cavα1 and Cavβ subunits showed stronger interference effects than single-gene silencing. This study provides insights for further study of VGCCs in plant-parasitic nematodes.
This paper investigates the effects of substituents in PNP-type ruthenium complexes in the catalytic hydrogenation of CO2 to formate using the DFT method. Six groups were considered as substituents ...linked to the P atom of the PNP ligand: hydrogen, methyl, iso-propyl, tert-butyl, cyclopentyl, and cyclohexyl. The substituent effects were analyzed from the perspectives of steric hindrance and promotion of hydrogen bonding. With the joint functions of steric hindrance and hydrogen bonding promotion during the CO2 coordination step, hydride addition step, and HCOO− rotation step, these groups exhibited very different substituent effects. The results showed that the methyl group was the most favorable substituent when the solvent’s effects were not included, as it formed hydrogen bonding with relatively weak steric hindrance. The second favorable substituent was the iso-propyl group, while the tert-butyl group was the most unfavorable one, due to remarkable steric hindrance. When the substituent was cyclopentyl or cyclohexyl, the complex provided a wider open space for the reaction compared with the tert-butyl-substituted complex, because cyclopentyl and cyclohexyl are cyclic groups. Therefore, the principle for choosing the substituent in PNP-type complexes allowing the design of highly efficient catalysts for CO2 hydrogenation indicates that more hydrogen atoms but wider open space are ideal. In addition, the substituent’s effects can be markedly impacted by the solvent used.
In this work, an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA (mono-ethanol-amine) and NaOH solutions. The effects of gas flow rate, the liquid to gas ...ratio (L/G), the CO2 concentration on the CO2 removal efficiency (η) and the volumetric overall mass transfer coefficient (KGav) were investigated. The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance. For the aqueous MEA and NaOH solutions, the experimental results show that the η decreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G. The effects on KGav are more complicated than those for η. When the CO2 concentration is low (3 vol%), KGav increases with increasing gas flow rate while decreases with increasing L/G. However, when the CO2 concentration is high (9.5 vol%), as the gas flow rate and L/G increases, KGav increases first and then decreases. The aqueous MEA solution achieves higher η and KGav than the aqueous NaOH solution. The air-blast atomizing column shows a good performance on CO2 capture.
The rice root-knot nematode
is increasingly widely distributed in China and has had a severe incidence in Hunan Province. It is thus necessary to investigate its population dynamics in paddy fields. ...This study was conducted to ascertain the effect of direct-seeded rice agroecosystems on the population dynamics of
and root gall development in rice. The results indicated that the population density of
in soil was markedly influenced by the agroecosystem, rainfall and temperature. The population density of
J2, and eggs in the soil and root galls, were significantly larger in the dry aerobic rice agroecosystem and in the rain-fed upland agroecosystem than in the lowland double-rice cropping sequence agroecosystem. As it can affect soil moisture rainfall was the key factor affecting the density of nematodes in both the rain-fed upland agroecosystem and the dry aerobic rice agroecosystem. Field flooding was still an effective way to reduce the population density of
. In addition, we observed that
can lay eggs outside rice roots under laboratory conditions. Therefore, we propose a hypothesis that
lays egg masses within roots when the soil moisture is high, but lays eggs outside when the soil moisture is suitable. By clarifying the population dynamics of
in different types of direct-seeded rice agroecosystems, this study is conducive to controlling rice root-knot nematodes.
A bicrystalline titanium dioxide nanofiber with enhanced photocatalytic activity was synthesized from potassium titanate K2Ti2O5 via ion exchange and calcination. The nanofiber has a core−shell ...crystalline structure with a thin TiO2(B) phase sheathing the anatase core, as characterized by X-ray diffraction, Raman spectroscopy, and high-resolution transmission microscopy (HRTEM). From HRTEM and local electron diffraction patterns, the two crystalline phases form a coherent interface with the 0.34-nm spacing between the (102) planes of TiO2(B) matching that between the anatase (101) lattice planes. The core−shell anatase/TiO2(B) nanofiber shows enhanced photocatalytic activity in iodine oxidation reaction with a 20−50% increase in extent of reaction compared to either single-crystal anatase or single-crystal TiO2(B) nanofibers. Anatase and TiO2(B) have the same band gap value of 3.2 eV, while theoretical calculations show the conduction band (CB) and valence band (VB) energies in anatase are both lower than the corresponding CB and VB energies in TiO2(B). The enhanced photocatalytic property may be due to enhanced and concerted charge mobility toward or away from the anatase/TiO2(B) interface. The special structure−property relationship can provide a new strategy to design and fabricate efficient photocatalytic and photovoltaic materials.
In this work, we study the trans influence of boryl ligands and other commonly used non-boryl ligands in order to search for a more active catalyst than the ruthenium dihydride complex Ru(PNP)(CO)H2 ...for the hydrogenation of CO2. The theoretical calculation results show that only the B ligands exhibit a stronger trans influence than the hydride ligand and are along increasing order of trans influence as follows: –H < –BBr2 < –BCl2 ≈ –B(OCH)2 < –Bcat < –B(OCH2)2 ≈ –B(OH)2 < –Bpin < –B(NHCH2)2 < –B(OCH3)2 < –B(CH3)2 < –BH2. The computed activation free energy for the direct hydride addition to CO2 and the NBO analysis of the property of the Ru–H bond indicate that the activity of the hydride can be enhanced by the strong trans influence of the B ligands through the change in the Ru–H bond property. The function of the strong trans influence of B ligands is to decrease the d orbital component of Ru in the Ru–H bond. The design of a more active catalyst than the Ru(PNP)(CO)H2 complex is possible.
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