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Global efforts are focused on discussing effective measures for minimizing the impact of COVID-19 on global community. It is clear that the ongoing pandemic of this virus caused an immense threat to public health and economic development. Mathematical models with real data simulations are powerful tools that can identify key factors of pandemic and improve control or mitigation strategies. Compared with integer-order and left-hand side fractional models, two-side fractional models can better capture the state of pandemic spreading. In this paper, two-side fractional models are first proposed to qualitative and quantitative analysis of the COVID-19 pandemic. A basic framework are given for the prediction and analysis of infectious diseases by these types of models. By means of asymptotic stability analysis of disease-free and endemic equilibrium points, basic reproduction number R 0 can be obtained, which is helpful for estimating the severity of an outbreak qualitatively. Sensitivity analysis of R 0 is performed to identify and rank key epidemiological parameters. Based on the real data of the United States, numerical tests reveal that the model with both left-hand side fractional derivative and right-hand side fractional integral terms has a better forecast ability for the epidemic trend in the next ten days. Our extensive computational results also quantitatively reveal that non-pharmaceutical interventions, such as isolation, stay at home, strict control of social distancing, and rapid testing can play an important role in preventing the pandemic of the disease. Thus, the two-side fractional models are proposed in this paper can successfully capture the change rule of COVID-19, which provide a strong tool for understanding and analyzing the trend of the outbreak. [ABSTRACT FROM AUTHOR]

• When banks issue inclusive loans, given the asymmetry between costs and benefits, phenomena that could be termed "balance increase without profit increase, or even with no profit", and "doing business at a loss" emerge; these negatively impact bank performance and efficiency and are attributable principally to SMEs. • Digital inclusive finance effectively offsets the adverse effects of traditional inclusive loans, and FinTech boosts bank performance. • This paper also finds that the positive effect of FinTech is attributable principally to the risk adjustment effects afforded. These reduce information asymmetry and transaction costs. In recent years, the Chinese banking industry has increasingly used financial technology (FinTech) to increase the credit supply to key areas of inclusive finance, as "impulse" and "fee reduction and profit-sharing" behaviours have exerted pressure on bank performance. This paper analyses the impacts of FinTech on bank performance and the risk adjustment mechanism of FinTech. The results show that, first, when banks issue inclusive loans, the phenomenon of increasing the balance without a corresponding increase in profits, or even resulting in no profits develops because of cost-benefit asymmetry. "Doing business at a loss" negatively impacts bank performance; these losses are primarily associated with small and micro enterprises (SMEs). Second, digital inclusive finance effectively mitigates the negative impacts of traditional inclusive loans, and FinTech boosts bank performance. Third, the positive effects of FinTech are attributable to risk adjustment effects that reduce information asymmetry and transaction costs. This paper demonstrates that digitalisation empowered by FinTech has improved the service efficiency and customer experience of inclusive finance, as well as other business income and bank performance. Banks must be cautious when analysing the risks and benefits afforded by internet platform flow-data. Each head office should formulate a digital financial strategy and unify the deployment of innovative FinTech applications. Bank branches should promote such transformation but must engage in digital inclusive finance differently, based on the level of local FinTech development. This optimises the allocation of credit resources. [ABSTRACT FROM AUTHOR]

• The active oxygen on Pd/Sn 1−x Ce x O 2 (Ce-rich) is mainly lattice oxygen. • The active oxygen on Pd/Sn 1−x Ce x O 2 (Sn-rich) is mainly chemisorbed oxygen. • The active oxygen on Sn-rich oxide has better mobility than that on Ce-rich oxide. The properties of Sn-Ce solid solution have a significant effect on the CO oxidation performance of the Pd/Sn 1-x Ce x O 2 catalyst. Herein, we compared the effects of Sn-rich and Ce-rich supports on the catalytic performance of the Pd/Sn 1-x Ce x O 2 catalysts. Our results show that the active oxygen species on the Ce-rich and Sn-rich supports are mainly the lattice oxygen species and the chemisorbed oxygen species, respectively. Although the active oxygen species on the Ce-rich supports have higher intrinsic activity, the active oxygen species on the Sn-rich supports have better mobility. It leads to an interesting phenomenon that the change trend of the activity of the Pd/Sn 1-x Ce x O 2 catalysts with temperature is consistent with that of their supports. Compared with the Ce-rich supports and the corresponding supported Pd catalysts, the catalytic activity of the Sn-rich supports and the corresponding supported Pd catalysts increased faster with the increase of temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • 35% H 6 PV 3 MoW 8 O 40 /AC-Ag catalyst was prepared. • A high oil conversion of 91.3% was achieved over the solid catalyst. • The catalyst has good recyclability and high resistance of acid and water. • Transesterification and esterification reactions can be achieved simultaneously. The heterogenization of Keggin-structure heteropoly acids (HPAs) has been proposed as a strategy to improve their application in biodiesel production in an attempt to comply the green and clean production demand. Herein, the commercial activated carbon (AC) was firstly modified with different metal ions (Cs+, K+ and Ag+), and then the H 6 PV 3 MoW 8 O 40 acid was incorporated into as-modified AC supports, so as to prepare HPAs-based solid catalysts. By screening tests, the 35%H 6 PV 3 MoW 8 O 40 /AC-Ag hybrid solid catalyst showed highly catalytic performance for transesterification of soybean oil. The best oil conversion of 91.3% was achieved under optimized conditions: methanol/oil molar ratio of 30:1, reaction time of 10 h, reaction temperature of 140 °C and catalyst dosage of 8 wt.%. Characterization results of XRD, IR, ICP and TG indicated that H 6 PV 3 MoW 8 O 40 was highly dispersed on the AC-Ag support as the loading was less than 35%. Proton exchange with Ag may contribute to the highly dispersion of H 6 PV 3 MoW 8 O 40 on the support and thus enhance the interaction of the heteropoly acids with the support, thereof leading to the increased catalytic stability. The as-prepared 35%H 6 PV 3 MoW 8 O 40 /AC-Ag catalyst was easily recycled and had good resistance to free fatty acid (FFA) and water, which were usually included in the low-quality oils. Moreover, as a bifunctional catalyst, the solid acid catalyst could simultaneously catalyze the transesterification of soybean oil and esterification of FFAs, and a probable mechanism of the catalytic process was also proposed. All the features of this novel solid catalyst are more advantageous than the homogenous H 6 PV 3 MoW 8 O 40 catalyst, successfully creating an efficient and sustainable approach of biodiesel production especially from the low-quality oils. [ABSTRACT FROM AUTHOR]

Abstract: A series of Li-based lean-burn NO x trap (LNT) catalysts Pt/Li/TiO2–MO x (M=Al, Zr, Si, Sn) were prepared by sequential impregnation with the supports TiO2–MO x synthesized by co-precipitation. The support effect on the NO x storage and sulfur-resisting performance of Pt/Li/TiO2–MO x catalysts was investigated carefully. The NO x storage capacity of fresh Pt/Li/TiO2 is greatly improved by doping with Al2O3 or ZrO2 due to the remarkably increased specific surface area and the oxidation ability of the catalysts. HR-TEM and H2-chemisorption results reveal that the oxidation ability of Pt/Li/TiO2–MO x is mainly determined by Pt crystallite size. Larger Pt crystallites correspond to stronger oxidation ability. The regeneration of sulfated Pt/Li/TiO2–MO x strongly depends on the total acidity of the supports, including Brønsted and Lewis acid; the supports with larger acidity possess higher ability of sulfur-resistance and regeneration. The results of in situ DRIFTS show that over Pt/Li/TiO2–MO x (M=Al, Zr, Si, Sn) NO x is mainly stored as ionic nitrate species at 350°C. Taking the NSC and regeneration ability into account, the catalyst Pt/Li/TiO2–Al2O3 is the most promising one for practical application. [Copyright &y& Elsevier]

In this work, the physico-chemical properties of the La 1-x Sr x Co 0.8 Fe 0.2 O 3 (x = 0, 0.3，0.4，0.5，0.6) catalysts were systematically studied as well as their catalytic activity for NO oxidation. When Sr2+ substituted at La3+ site, [CoO 6 octahedral distortion is amended and the crystal structure transited from rhombohedral to cubic. Co(III) electronic configuration turned from high/intermediate spin state to low spin sate with empty e g filling. Imbalanced positive charge induced by Sr2+ was compensated by tetravalent Co(IV) ions and oxygen deficiencies together. All these factors resulted in better reducibility of Co, increasing oxygen deficiencies and more mobile oxygen species. Thus, NO conversion of 67–69% was attained over the Sr-doped catalysts at 300 °C, much higher than the undoped catalysts (NO conversion of 24.3%). A significant decrease of the apparent activation energy (E a), from 68 kJ/mol down to ~52 kJ/mol, was observed as well. Based on the kinetics results, NO oxidation over the perovskite catalysts is a typical superficial process determined by adsorbed NO and surface oxygen species. Image 1 • Sr doping amended the [CoO 6 octahedral distortion in the LaCo 0.8 Fe 0.2 O 3 structure. • Sr doping decreased e g filling of Co and prolonged Co–O distance, which was favorable for NO adsorption. • Sr doping produced more oxygen deficiencies, which was favorable for O 2 adsorption. • The La(Sr)Co(Fe)O 3 perovskites exhibited much higher NO oxidation activity and lower Ea than the LaCo(Fe)O 3 perovskites. [ABSTRACT FROM AUTHOR]

Improving the reactant mass transfer on the catalyst surface is a feasible approach to fabricate a robust solid catalyst for efficiently promoting the biomass macromolecules-involving reactions, specifically for biodiesel production by using non-edible acidic oils as feedstocks. In this premise, to reduce the mass transfer resistance, the hierarchical porous SOM-ZIF-8 was firstly synthesized using polystyrene spheres (PS) as templates and then employed as catalyst supports for loading of Keplerate-type polyoxomolybdates {Mo 132 } to prepare a novel {Mo 132 }@SOM-ZIF-8 solid acid catalyst. The catalyst characterization results revealed that the active species of {Mo 132 } clusters were well-dispersed on the SOM-ZIF-8 support and the primary framework of the SOM-ZIF-8 support remained nearly unaltered after the preparation processes. This prepared catalyst featured three-dimensional ordered hierarchical porous structure and dual Bronsted-Lewis acid sites, with a large surface area of 736.26 m2/g and high acidity of 903 μmol/g, presenting high activities for concurrent triglyceride transesterification and free fatty acids (FFAs) esterification. With the acidic soybean oils as feedstocks, 93.9 % of oil conversion and full FFA conversion to biodiesel were achieved over this solid catalyst at 130 °C for 8 h with a catalyst loading of 2 wt%, thus imparting the great potential for a one-pot efficient biodiesel manufacture from the acidic oils to comply with the demand of green and clean production. The synergy between the hierarchical porous structure and the strong acidity emerged, thus boosting the catalytic performance of this solid catalyst for the heterogeneous biodiesel production. The good FFA and moisture-resistance capacity was shown for this catalyst even in the case of moisture content of 3 % and FFA content of 25 %. Further, this catalyst showed excellent reusability without significantly losing its catalytic performance even after five runs, providing a deeper insight into constructing efficient solid catalysts with hierarchical porous structure that are utilized for cost-effective production of biodiesel from the non-edible acidic oils. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of feasible ecofriendly processes for biodiesel production is highly desirable to meet the requirement of green chemistry and sustainable development. To reach this goal, the molybdenum and zirconium oxides were incorporated into commercial available KIT-6, mesoporous silica nanoparticle, by a solvothermal method, to form MoO 3 /ZrO 2 /KIT-6 catalyst. The targeted solid composite catalysts were structurally characterized using XRD, TEM, SEM, XPS, EDS, TG, and nitrogen porosimetry measurement. The characterization results showed that the ordered porous structure of the support was well persevered with high surface area, and the molybdenum and zirconium oxides could be highly dispersed on the mesoporous support. The acidic nature of the solid catalyst was evaluated in detail by means of NH 3 -TPD and infrared spectra of adsorbed pyridine techniques. It was indicated that the acidities of the solid catalysts, with both Brønsted and Lewis acid sites, could greatly affected their catalytic activity. This catalyst displayed high activities to the transesterification of triglycerides and esterification of free fatty acids (FFAs) simultaneously owing to the synergistic effect of Brønsted and Lewis acid sites, thus achieving one-pot heterogeneous production of biodiesel as the low-quality oil was used as feedstocks. The influence of reaction parameters and the catalyst reusability were also investigated, and the best oil conversion of 92.7% was obtained under the optimized reaction conditions. The targeted catalyst exhibited a better FFAs and water tolerant for the reaction, advantageously with no noticeable decline in the catalytic performance even after five reaction cycles. [Display omitted] • MoO3/ZrO2/KIT-6 catalysts with both Brönsted and Lewis acid site were prepared. • The catalyst was effective for one-pot biodiesel production from low-quality oils. • The solid acid catalysts were characterized by various techniques. • Transesterification and esterification reactions can be achieved simultaneously. • The catalyst has good recyclability and high resistance to acid and water. [ABSTRACT FROM AUTHOR]

The exploration of efficient and recyclable catalysts is highly desirable for catalytic biodiesel manufacture from low-grade acidic oils, in response to the demand of clean production and environmental concerns. For this aim, phosphotungstic acid (HPW) was firstly modified by tin metal, and then embedded on ZIF-8 metal-organic formworks (MOFs) to synthesize the SnPW@ZIF-8 catalyst. Catalyst characterization results revealed that the active species of Sn-doped HPW with Keggin-type anion structure were well-dispersed on the ZIF-8 support, and this catalyst featured high surface area with dual Brönsted-Lewis acid sites, posing enhanced catalytic performances to the oil transesterification and esterification of free fatty acids (FFAs) presented in oils. By applying this catalyst, 92.8 % of oil conversion and 97.4 % of FFAs conversion were concurrently achieved under the optimized conditions, rendering one-pot conversion of low-grade acidic oils to biodiesel and minimizing the complex and tedious separation processes. Moreover, the higher water and FFA-resistance capacity was shown for this catalyst, imparting its more suitable for the efficient biodiesel production particularly with the acidic oils as feedstocks. Further, this catalyst could still remained high catalytic efficiency after five cycle reuses due to the strong interactions of the SnPW with the imidazole groups in the ZIF-8, making it to have the potential of cost-effective and efficient production of biodiesel from the low-grade acidic oils. [Display omitted] • SnPW@ZIF-8 solid catalyst with duai Brönsted-Lewis acid site were prepared. • This catalyst was effective for one-pot biodiesel production from low-grade oils. • Oil transesterification and FFA esterification can be achieved simultaneously. • This catalyst has good recyclability and high resistance to acid and moisture. [ABSTRACT FROM AUTHOR]

Herein, we reduced the ZnO-modified copper phyllosilicate to synthesize a series of Cu/ZnO/SiO 2 catalysts ( x CuZn/SiO 2 ) which were mixed with γ-Al 2 O 3 for dimethyl ether steam reforming (DME SR). The structure and the formation of copper phyllosilicate were systematically characterized by nitrogen adsorption, XRD and IR. The novel synthetic route led to the remarkably high dispersion of copper species and adjustable Cu 0 /Cu + ratio on the catalyst surface, resulting in the superior catalytic performance for DME SR. The amount of Cu 0 and Cu + sites on the catalyst surface was dramatically affected by ZnO loading, and the turnover frequency results indicated that the 4CuZn/SiO 2 catalyst (Cu/Zn = 4) with the Cu 0 /Cu + ratio of 1 showed the highest catalytic performance. The XPS, H 2 -TPR and TEM results revealed the existence of strong interaction between Cu species and ZnO on the reduced 4CuZn/SiO 2 catalyst, which suppressed the reverse water-gas reaction and prevented the sintering of copper. [ABSTRACT FROM AUTHOR]

• We propose a novel two-stage aware training framework for siamese networks, in which position-aware and appearance-aware training schemes are presented to optimize the shallow and the deep network layers, respectively. This contribution helps siamese tracker to achieve precise and robust visual tracking. • An effective feature selection module is presented to solve the online adaptation problem of Siamese tracker. By analyzing the changing principle of feature distribution, the module combines diverse attention networks in a unique way to explore the real discriminative features for the current object. • The proposed tracker is evaluated on four popular benchmark datasets extensively. The results demonstrate that the tracker performs better than other state-of-the-art methods in terms of accuracy and robustness. Siamese networks have achieved great success in visual tracking with the advantages of speed and accuracy. However, how to track an object precisely and robustly still remains challenging. One reason is that multiple types of features are required to achieve good precision and robustness, which are unattainable by a single training phase. Moreover, Siamese networks usually struggle with online adaption problem. In this paper, we present a novel two-stage aware attentional Siamese network for tracking (Ta-ASiam). Concretely, we first propose a position-aware and an appearance-aware training strategy to optimize different layers of Siamese network. By introducing diverse training patterns, two types of required features can be captured simultaneously. Then, following the rule of feature distribution, an effective feature selection module is constructed by combining both channel and spatial attention networks to adapt to rapid appearance changes of the object. Extensive experiments on various latest benchmarks have well demonstrated the effectiveness of our method, which significantly outperforms state-of-the-art trackers. [ABSTRACT FROM AUTHOR]

CO 2 capture is currently the most effective way to reduce global carbon emissions, which leads to the emergence of novel gas hydrate method. In this work, the significant role of graphene oxide (GO) in enhancing the dynamic behaviors of post-combustion CO 2 capture via the hydrate formation was investigated. Firstly, at the gas-liquid interface, the induction of GO increased the amount of gas transfer, and shortened the induction time for the hydrate nucleation at the heterogeneous nucleation sites provided by GO, which attracted CO 2 molecules assembling on the GO layer to participate in the hydrate nucleation based on the molecular dynamics (MD) simulations. More importantly, the hydrate growth rate was nearly doubled in 0.05 wt% GO and 4 mol% tetrahydrofuran (THF) mixed accelerators than that in pure THF and sodium dodecyl sulfate (SDS) mixed systems, which greatly boosted the gas storage capacity of CO 2 in the form of compact solid hydrates. Consequently, CO 2 separation efficiency achieved up to 76 % in the GO based accelerators, enhanced by 23.2 % compared to that in pure THF and the SDS mixed systems. The present study could provide insights into the development of new type of nanomaterial accelerators for CO 2 capture via the gas hydrate method. [Display omitted] • GO promoted the interfacial gas transfer and shortened the induction time for the hydrate nucleation. • The hydrate growth rate and gas storage capacity of CO 2 were greatly boosted by GO based accelerators. • The enhanced kinetic behavior resulted in the superior CO 2 separation efficiency of 76% for the flue gas. [ABSTRACT FROM AUTHOR]

• The hot-water pretreatment can generate new Brønsted acid sites. • The hot-water pretreated H-MOR shows high activity for DME carbonylation. • The hot-water pretreated H-MOR accelerates the formation of methoxy groups. • The residue water molecules will inhibit DME carbonylation. Herein, we report the effect of the hot-water pretreatment on the catalytic activity of the H-mordenite (H-MOR) zeolite for DME carbonylation. The structure and acidity of the H-MOR catalysts pretreated by hot water were systematically characterized by XRD, nitrogen adsorption, SEM, H 2 O-TPD, NH 3 -TPD, 1H NMR and NH 3 -DRIFTS technologies. With the increase of the duration of the hot-water pretreatment, the catalytic activity shows a volcano-type variation. The H-MOR catalyst pretreated by hot water for 10 min at 573 K displays the highest catalytic activity among all of the catalysts. The appropriate duration of the hot-water pretreatment can generate new medium strong and strong Brønsted acid sites, which changes the microenvironment in the pores of H-MOR. Additionally, the newly generated Brønsted acid sites will accelerate the first step of DME carbonylation, that is, DME reacts with the Brønsted acid sites of the zeolite forming surface methoxy groups and methanol, improving the catalytic activity of the catalysts. However, too long duration of the hot-water pretreatment will remain water molecules in H-MOR, which inhibits DME carbonylation. [ABSTRACT FROM AUTHOR]

For the purpose of fabricating an efficient solid acid catalyst for biodiesel production from low-grade acidic oils, bimetallic silica mesoporous composites with different Zr/Al molar ratios were initially synthesized via a facile one-step hydrothermal method, and then sulfated with sulfuric acid at different concentrations to get a series of sulfated Zr x -Al y -KIT-6 catalysts (denoted as SZA-K, where x/y represents the molar ratio of Zr to Al). The sulfated bimetallic solid catalysts were fully characterized by using XRD, FT-IR, TEM, SEM, EDS, NH 3 -TPD, and nitrogen porosimetry measurements. Results showed that the remarkable amount of acidic sites in the catalysts was derived from the Zr and Al incorporation and further sulfation, and specifically, the Zr4+ and Al3+ could afford abundant weak acid sites while the inductive effect of SO 4 2− species greatly influences the acidic strength of this solid catalyst. In combination with the enhancement in mass transfer resulting from the inherent interconnected mesoporous structure, the SZA-K catalyst could facilitate the transesterification reaction to take place efficiently. The sulfated Zr 5 –Al 1 -KIT-6 catalyst (Zr/Al molar ratio of 5/1, treated using 0.75 mol/L sulfuric acid for 12 h) exhibited enhanced acid strength with larger number of acidic sites (7.81 mmol/g), resulting in a high catalytic performance to the oil transesterification reaction. An oil conversion of 96.3% was attained for the transesterification reaction performed at 120 °C for 7 h by using a methanol/oil molar ratio of 20:1 and a catalyst dosage of 6 wt%. Further, this solid catalyst exhibited better acid and water-resistance capacity with above 80% of oil conversion even with 10% of free fatty acid (FFA) and 2% of moisture present in the low-grade acidic oils. Meanwhile, the good reusability was shown for this catalyst with 80.1% conversion even after reusing for three cycles. The good stability of the solid catalyst was resulted from the strong interactions between the acidic species and the bimetallic composite support. Bimetallic Zr x -Al y -KIT-6 modified with sulfate as acidic catalyst for biodiesel production from low-grade acidic oils. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a controller design approach based on LMI optimization method is proposed for the two-axis gimbal platform in finite time application. This method is based on the linear parameter varying (LPV) model of the two-axis gimbal platform, considering the cross-coupling problem between the pitch and yaw channel. Firstly, the dynamic equation of the two-axis gimbal platform is analyzed and its LPV model is obtained. Then, the sufficient conditions which can ensure the LPV system is finite time bounded(FTB) are introduced, and the controller is designed accordingly. Finally, the performance of the platform with finite time controller and PI controller is analyzed qualitatively. The results show that the proposed controller can guarantee the tracking accuracy in finite time and effectively suppress the coupling interference between the pitch and yaw channel. [ABSTRACT FROM AUTHOR]

The error of a MEMS gyroscope is highly dependent on the ambient temperature. Traditionally, it is modeled with polynomials, which cannot achieve sufficient accuracy. In order to solve this problem, a Parameter-Interpolation method is proposed to model and calibrate the deterministic error of a MEMS gyroscope. First, the establishment of a MEMS gyroscope's error model and the calibration methods are discussed. Based on the traditional method, we come up with the Parameter-Interpolation (PI) model. Its parameters vary with temperature and each group of parameters is saved separately. The gyroscope is calibrated through interpolation. Then, we design a multi-position experiment test using a thermal turntable to test the traditional and the Parameter-Interpolation (PI) methods. Finally, we process the data collected in the experiments and compare the results of these two methods. Results show that both methods are valid to improve the accuracy of a MEMS gyroscope but the Parameter-Interpolation (PI) method is more effective. [ABSTRACT FROM AUTHOR]

Abstract: Arabidopsis heat shock factor HsfA1a is present in a latent, monomeric state under normal conditions; its activation involves heat stress-induced trimerization, binding to heat shock element in target promoters, and the acquisition of transcriptional competence. HsfA1a is an important regulator for heat stress-induced gene expression and thermotolerance. However, it is not clear whether HsfA1a is directly activated by stress and the mechanisms of the stress signaling are poorly understood. We analyzed HsfA1a activation by trimerization and DNA-binding assays in vitro and in vivo in response to heat stress, low/high pH, and hydrogen peroxide treatments. Our results show that purified recombinant HsfA1a was activated by these stress treatments in vitro. The same treatments also induced the binding to HSP18.2 and HSP70 promoters as examined by chromatin immunoprecipitation, and the HsfA1a DNA binding paralleled the mRNA expression of its target genes induced by different stresses. Stress-induced DNA-binding could be reversed, both in vitro and in vivo, by subsequent incubation with reducing agents (DTT, NADPH). These data suggest that HsfA1a can directly sense stress and become activated, and this process is dependent on the redox state. An N-terminal deletion of the amino acid residues from 48 to 74 negatively affected pH- and hydrogen peroxide-, but not heat-stress sensing. [Copyright &y& Elsevier]

Abstract: This report describes advances in the anther culture of Zantedeschia aethiopica. Important factors for improvement as compared to the earlier procedure were: (1) using flowers from inflorescences developed at relatively low temperature during winter, (2) high temperature stress treatment at 32°C for 2 days in the beginning of the culture, (3) use of Gamborg B5 as anther culture medium, and (4) addition of sucrose at high concentration of 8% in the culture medium. Plants were obtained via a callus phase. Frequency of anthers producing calli was around 4–5%. About 87% of the calli gave regenerants, of which 52% were haploid, 36% were diploid and the rest had other ploidy levels. In addition to chromosome counting, cytological examination of the microspore development and amplified fragment length polymorphism (AFLP) analysis of the regenerants showed that haploid as well as diploid plants originated from the microspores. Finally, 12 doubled haploid (DH) plants could be produced from each inflorescence. One quarter of the DHs equaled the original cultivar in growth vigor, while more than one third showed good fertility, indicating that inbreeding depression was not so severe in this heterozygous species. The improved protocol now enables production of sufficient number of DHs for application of haploid technology in genetic improvement and breeding of Z. aethiopica. [Copyright &y& Elsevier]

Abstract: The BaFeO3−x perovskite catalyst was prepared by sol–gel method for NO x storage under lean-burn conditions. During the catalyst precursor calcination, a series of complex solid reactions happened, and the BaCO3, formed during citric acid combustion, played a key role to react with the spinel species achieving the aimed perovskite. On the Ba–Fe–750F catalyst, the perovskite phase and the small amount of spinel phase were evidenced by XRD, and some well dispersed carbonate was also detected by FT-IR. Under lean-burn conditions, the NO x was easily stored on the Ba–Fe–750F catalyst, and its optimized NO x storage capacity (NSC), i.e. 333.5μmolg−1, was obtained at 400°C. At above 400°C, the stored nitrate became unstable and decomposed, resulting in the sharp decrease of NSC. Two kinds of the NO x storage sites were identified by in situ DRIFTS experiments that the carbonate remaining on the catalyst could transform to monodentate nitrate, and the A site Ba in the perovskite structure could directly bind with NO x to form N-bounded nitrate. This BaFeO3−x perovskite catalyst was a potential NO x storage material with noble metal free. [ABSTRACT FROM AUTHOR]