Converting ceria polyhedral nanoparticles into single-crystal nanospheres

Ceria nanoparticles are one of the key abrasive materials for chemical-mechanical planarization of advanced integrated circuits. However, ceria nanoparticles synthesized by existing techniques are irregularly faceted, and they scratch the silicon wafers and increase defect concentrations. We developed an approach for large-scale synthesis of single-crystal ceria nanospheres that can reduce the polishing defects by 80% and increase the silica removal rate by 50%, facilitating precise and reliable mass-manufacturing of chips for nanoelectronics. We doped the ceria system with titanium, using flame temperatures that facilitate crystallization of the ceria yet retain the titania in a molten state. In conjunction with molecular dynamics simulation, we show that under these conditions, the inner ceria core evolves in a single-crystal spherical shape without faceting, because throughout the crystallization it is completely encapsulated by a molten 1- to 2-nanometer shell of titania that, in liquid state, minimizes the surface energy. The principle demonstrated here could be applied to other oxide systems.     

Identification of a novel locus Rmo2 conditioning resistance in barley to host-specific subgroups of Magnaporthe oryzae

Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome.     

Immunoblotting, ELISA and culture evidence for Chlamydiaceae in sows on 258 Belgian farms

The prevalence of Chlamydiaceae infections on 258 closed pig breeding farms in Belgium was examined. For this purpose, 258 farms were randomly selected in the provinces West-Vlaanderen (44%), Oost-Vlaanderen (20%), Antwerpen (10%) and Vlaams-Brabant (6%). Of all farms examined, 96.5% were positive for Chlamydia-specific antibodies in ELISA and most were moderately to strongly positive. ELISA results revealed only 9 (3.5%) sero-negative farms. None of the ELISA negative sera reacted in immunoblotting. Only 212 of 249 ELISA positive sera reacted positive in immunoblotting. Additionally, 23 autopsy samples were examined by isolation in Vero cells. The major outer membrane sequence of the one isolate obtained showed 98.6% amino acid homology to the one of Chlamydophila psittaci strain CP3, formerly isolated from a pigeon. Present observations indicate that chlamydial infections are nearly endemic in the Belgian pig population and that Belgian pigs can become infected with C. psittaci. Nevertheless, the role and significance of Chlamydiaceae as pathogens in pigs remain unsolved and require further investigation.     

Anti-Inflammatory Components of the Starfish Astropecten polyacanthus

Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer’s disease, Parkinson’s disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC₅₀ values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the production of IL-12 p40 with values of 6.55 ± 0.18 and 5.06 ± 0.16 μM, respectively. Moreover, compounds 2 (IC₅₀ = 34.86 ± 0.31 μM) and 6 (IC₅₀ = 79.05 ± 2.05 μM) exhibited moderate inhibitory effects on the production of IL-12 p40, whereas compounds 3 (IC₅₀ = 22.80 ± 0.21 μM) and 4 (IC₅₀ = 16.73 ± 0.25 μM) moderately inhibited the production of TNF-α and IL-6, respectively.     

Penicillinolide A: A New Anti-Inflammatory Metabolite from the Marine Fungus Penicillium sp. SF-5292

In the course of studies on bioactive metabolites from marine fungi, a new 10-membered lactone, named penicillinolide A (1) was isolated from the organic extract of Penicillium sp. SF-5292 as a potential anti-inflammatory compound. The structure of penicillinolide A (1) was mainly determined by analysis of NMR and MS data and Mosher’s method. Penicillinolide A (1) inhibited the production of NO and PGE₂ due to inhibition of the expression of iNOS and COX-2. Penicillinolide A (1) also reduced TNF-α, IL-1β and IL-6 production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), a competitive inhibitor of HO activity, it was verified that the inhibitory effects of compound 1 on the production of pro-inflammatory mediators and NF-κB DNA binding activity were partially associated with HO-1 expression through Nrf2 nuclear translocation.     

The Contribution of Various Components to pH Buffering Capacity of Acrisols in Southeastern Vietnam

This paper examined the contribution of various soil components to pH buffering capacity (pH_BC) of haplic Acrisols in an upland area of Southeastern Vietnam. Sampling was conducted in 2016 in Tan Bien district, Tay Ninh province at seven sites from the surface to 60-cm depth. Soils were very acidic (pH_H2O 4.53 ± 0.05). The pH_BC were very low, 0.46 ± 0.04 and 0.44 ± 0.05 cmol H⁺ kg^?1 pH^?1, respectively, for original samples and those from which soil organic carbon (SOC, 0.52 ± 0.09%) were removed. The contribution of Al³⁺ to pH_BC was remarkable while that of SOC was of little significance. The contribution of clay minerals to pH_BC was unclear due to the low (9.37 ± 0.76%) and kaolinite-dominated clay content. The current soil conditions indicated a potential for further soil acidification. Liming would be one of the measures to remediate soil acidity in the research area.     

Short-term carbon and nitrogen dynamics in soil,litterfall and canopy of a suburban native forest subjected to prescribed burning in subtropical Australia

Purpose

This study aimed to understand the mechanisms of the variations in carbon (C) and nitrogen (N) pools and examine the possibility of differentiating the burning effects from seasonal and pre-existed N limitations in a native suburban forest ecosystem influenced by prescribed burning in subtropical Australia.

Materials and methods

Soil and litterfall samples were collected from two study sites from 1 to 23 months since last burnt. Soil labile C and N pools, soil C and N isotopic compositions (δ¹³C and δ¹⁵N), litterfall mass production (LM), and litterfall total C, total N, δ¹³C and δ¹⁵N were analysed. In-situ gas exchange measurements were also conducted during dry and wet seasons for Eucalyptus baileyana and E. planchoniana.

Results and discussion

The results indicated that labile C and N pools increased within the first few months after burning, with no correlations with climatic factors. Therefore, it was possible that the increase was due to the burning-induced factors such as the incorporation of ashes into the soil. The highest values of soil and litterfall δ¹⁵N, observed when the study was commenced at the experimental sites, and their high correlations with climatic factors were indicative of long-term N and water limitation. The ¹³C signals showed that soil N concentrations and climatic factors were also two of the main factors controlling litterfall and foliage properties mainly through the changes in photosynthetic capacity and stomatal conductance.

Conclusions

Long-term soil N availabilities and climatic factors were the two of the main driving factors of C and N cycling in the studied forest sites. Further studies are needed to compare soil and litterfall properties before and after burning to profoundly understand the effects of prescribed burning on soil labile C and N variations.

     

High yield and nutritional quality of rice for animal feed achieved by continuous irrigation with treated municipal wastewater

Paddy and Water Environment - Two consecutive pilot-scale experiments were conducted to investigate the potential reuse of treated municipal wastewater (TWW) as an irrigation source for cultivating...     

农用柔性底盘偏置轴转向机构联动耦合控制策略及试验

针对农用柔性底盘前轮转向时两偏置轴转向机构难以保持联动关系而影响顺利转弯的问题,基于阿克曼转向几何与交叉耦合控制原理,设计了偏置轴转向机构联动耦合控制策略,采用模糊PID控制算法对两转向轮转角联动轮廓误差进行补偿,并依据方向盘信号大小和变化率对电磁摩擦锁PWM控制信号占空比进行调节,以匹配偏置电动轮转向的角速度,使两转向机构形成耦合而保持期望联动关系;基于MATLAB/Simulink对控制策略进行了仿真,且在硬化路面上实施了阶跃转向、蛇行转向及随机转向3种运动方式的试验验证,并对比分析了转角分配控制下的前轮转向效果。试验结果表明:耦合控制方法下柔性底盘前轮阶跃转向响应均在0.8 s内,左、右侧转角最大超调为1.3°;电磁摩擦锁的开闭可较好匹配电动轮的转向;左、右前轮对于各自目标角具有良好的跟踪性能;3种转向方式下最大与平均跟随误差值均小于分配控制方法;两轮联动的最大与平均转角轮廓误差分别为:阶跃转向1.2°与0.6°、蛇行转向1.1°与0.6°、随机转向1.0°与0.5°;耦合控制下仿真与试验转角的轮廓误差变化趋势一致,最大误差为2.2°,证明仿真模型合理有效。耦合控制下偏置轴转向机构联动控制效果优于转角分配控制,转向效果良好,该文提出的柔性底盘偏置轴转向机构联动耦合控制策略有效且可行。     

Short-term effects of organo-mineral enriched biochar fertiliser on ginger yield and nutrient cycling

Purpose

Biochar has agronomic potential but currently is too expensive for widespread adoption. New methodologies are emerging to reduce the cost such as enriching biochar with nutrients that match crops and soil requirements. However, the effects of biochar-based fertilisers on plant yield and soil nutrient availability have not been widely examined. This study investigated the effects of a novel organo-mineral biochar fertiliser in comparison to organic and commercial biochar fertiliser on ginger (Zingiber officinale Canton).

Materials and methods

There were four treatments: (1) commercial organic fertiliser (5 t ha^?1), as the control; (2) commercial biochar-based fertiliser (5 t ha^?1); (3) organo-mineral biochar fertiliser at low rate (3 t ha^?1); and (4) organo-mineral biochar fertiliser at high rate (7.5 t ha^?1). A replicated pot trial was established with black dermosol soil and ten replicate pots for each treatment. Ginger was planted and grown for 30 weeks. Plant growth, biomass, foliar nutrients and water extractable soil nutrients including phosphorus (P), potassium (K) and calcium (Ca) were examined.

Results and discussion

High rate organo-mineral biochar fertiliser increased soil P and K availability at week 30 (harvest) after planting, compared to all other treatments and low rate organo-mineral biochar fertiliser performed similarly to the organic control for P and K. High rate organo-mineral biochar fertiliser increased total foliar nutrient content at week 30 in P, K and Ca compared to commercial biochar fertiliser. High rate organo-mineral biochar fertiliser improved the commercial value of ginger (+?36%) due to a shift in the proportion of higher grade rhizomes. Low rate organo-mineral biochar fertiliser plants displayed similar yield, total dry and aboveground biomass to commercial organic fertiliser. Commercial biochar fertiliser had significantly lower biomass measures compared with other treatments as the rate applied had lower nutrient concentrations.

Conclusions

Our results show organo-mineral biochar fertilisers could be substituted for commercial organic fertilisers at low rates to maintain similar yield or applied at high rates to increase commercial value where economically feasible.