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Nitroethane (NE), 2-nitroethanol (NEOH) and 2-nitro-1-propanol (NPOH) were investigated in order to determine their inhibitory effects on in vitro ruminal fermentation and methane (CH4) production of a hay-rich substrate (alfalfa hay: maize meal = 4:1, w/w). The rumen liquor collected from cannulated Holstein dairy cows was incubated at 39 °C for 72 h. The addition of NE, NEOH and NPOH slowed down the fermentation process and notably decreased molar CH4 proportion by 96.8, 96.4 and 35.0%, respectively. The abundance of total methanogen and methanogens from the order Methanobacteriales were all decreased with NE, NEOH and NPOH supplementation. Meanwhile, the nitrocompound addition reduced mcrA gene expression, coenzyme F420 and F430 contents. The correlation analysis showed that CH4 production was correlated positively with the population abundance of total methanogens, Methanobacteriales, mcrA gene expression, coenzyme contents of F420 and F430. The nitrocompound addition decreased acetate concentration and increased propionate and butyrate concentrations in the culture fluid. In summary, both NE and NEOH addition presented nearly the same inhibitory effectiveness on in vitro CH4 production; they were more effective than NPOH. The results of the current study provide evidence that NE, NEOH and NPOH can dramatically decrease methanogen population, mcrA gene expression and the coenzyme content of F420 and F430 in ruminal methanogenesis.
While assessing the environmental impact of nuclear power plants, researchers have focused their attention on radiocarbon (14C) owing to its high mobility in the environment and important radiological impact on human beings. The 10 MW high-temperature gas-cooled reactor (HTR-10) is the first pebble-bed gas-cooled test reactor in China that adopted helium as primary coolant and graphite spheres containing tristructural-isotropic (TRISO) coated particles as fuel elements. A series of experiments on the 14C source terms in HTR-10 was conducted: (1) measurement of the specific activity and distribution of typical nuclides in the irradiated graphite spheres from the core, (2) measurement of the activity concentration of 14C in the primary coolant, and (3) measurement of the amount of 14C discharged in the effluent from the stack. All experimental data on 14C available for HTR-10 were summarized and analyzed using theoretical calculations. A sensitivity study on the total porosity, open porosity, and percentage of closed pores that became open after irradiating the matrix graphite was performed to illustrate their effects on the activity concentration of 14C in the primary coolant and activity amount of 14C in various deduction routes.
The very high temperature reactor (VHTR) is a development of the high-temperature gas-cooled reactors (HTGRs) and one of the six proposed Generation IV reactor concept candidates. The 10 MW high temperature gas-cooled reactor (HTR-10) is the first pebble-bed gas-cooled test reactor in China. A sampling system for the measurement of carbon-14 (14C) was established in the helium purification system of the HTR-10 primary loop, which could sample 14C from the coolant at three locations. The results showed that activity concentration of 14C in the HTR-10 primary coolant was 1.2(1) × 102 Bq/m3 (STP). The production mechanisms, distribution characteristics, reduction routes, and release types of 14C in HTR-10 were analyzed and discussed. A theoretical model was built to calculate the amount of 14C in the core of HTR-10 and its concentration in the primary coolant. The activation reaction of 13C has been identified to be the dominant 14C source in the core, whereas in the primary coolant, it is the activation of 14N. These results can supplement important information for the source term analysis of 14C in HTR-10 and promote the study of 14C in HTGRs.
This study investigated Echinococcus genotypes in patients with hydatidosis that reside in Inner Mongolia, Tibet or Qinghai Province by partially sequencing the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase 1 (nad1) genes. Cyst fluids were collected from 23 patients with hydatidosis and DNA was extracted. Portions of the cox1 and nad1 genes were amplified and subsequently sequenced. Sequencing analysis determined that one of the isolates contained Echinococcus multilocularis, and the other 22 isolates contained E. granulosus sensu lato. The isolates were then further classified based on genotype, and E. granulosus sensu stricto (s.s.) G1 (n = 20), E. granulosus s.s. G3 (n = 1) and E. canadensis G6/7 (n = 1) were identified. Additionally, the sequences were concatenated (pcox1 + pnad1) and 11 haplotypes were identified among the E. granulosus s.s. isolates (G1 and G3), with a shared common haplotype (H1) identified. Overall, these findings provide further understanding of the genetic patterns of Echinococcus in western and northern China.
Plant nitrogen (N) links with many physiological progresses of crop growth and yield formation. Accurate simulation is key to predict crop growth and yield correctly. The aim of the current study was to improve the estimation of N uptake and translocation processes in the whole rice plant as well as within plant organs in the RiceGrow model by using plant and organ maximum, critical and minimum N dilution curves. The maximum and critical N (Nc) demand (obtained from the maximum and critical curves) of shoot and root and Nc demand of organs (leaf, stem and panicle) are calculated by N concentration and biomass. Nitrogen distribution among organs is computed differently pre- and post-anthesis. Pre-anthesis distribution is determined by maximum N demand with no priority among organs. In post-anthesis distribution, panicle demands are met first and then the remaining N is allocated to other organs without priority. The amount of plant N uptake depends on plant N demand and N supplied by the soil. Calibration and validation of the established model were performed on field experiments conducted in China and the Philippines with varied N rates and N split applications; results showed that this improved model can simulate the processes of N uptake and translocation well.
High-energy electron radiography (HEER) has been proposed for time-resolved imaging of materials, high-energy density matter, and for inertial confinement fusion. The areal-density resolution, determined by the image intensity information is critical for these types of diagnostics. Preliminary experimental studies for different materials with the same thickness and the same areal-density target have been imaged and analyzed. Although there are some discrepancies between experimental and theory analysis, the results show that the density distribution can indeed be attained from HEER. The reason for the discrepancies has been investigated and indicates the importance of the uniformity in the transverse distribution beam illuminating the target. Furthermore, the method for generating a uniform transverse distribution beam using octupole magnets was studied and verified by simulations. The simulations also confirm that the octupole field does not affect the angle-position correlation in the center part beam, a critical requirement for the imaging lens. A more practical method for HEER using collimators and octupoles for generating more uniform beams is also described. Detailed experimental results and simulation studies are presented in this paper.
Marteilia refringens causes marteiliosis in oysters, mussels and other bivalve molluscs. This parasite previously comprised two species, M. refringens and Marteilia maurini, which were synonymized in 2007 and subsequently referred to as M. refringens ‘O-type’ and ‘M-type’. O-type has caused mass mortalities of the flat oyster Ostrea edulis. We used high throughput sequencing and histology to intensively screen flat oysters and mussels (Mytilus edulis) from the UK, Sweden and Norway for infection by both types and to generate multi-gene datasets to clarify their genetic distinctiveness. Mussels from the UK, Norway and Sweden were more frequently polymerase chain reaction (PCR)-positive for M-type (75/849) than oysters (11/542). We did not detect O-type in any northern European samples, and no histology-confirmed Marteilia-infected oysters were found in the UK, Norway and Sweden, even where co-habiting mussels were infected by the M-type. The two genetic lineages within ‘M. refringens’ are robustly distinguishable at species level. We therefore formally define them as separate species: M. refringens (previously O-type) and Marteilia pararefringens sp. nov. (M-type). We designed and tested new Marteilia-specific PCR primers amplifying from the 3’ end of the 18S rRNA gene through to the 5.8S gene, which specifically amplified the target region from both tissue and environmental samples.
The present study aim to explore temporal–spatial patterns of water use (WU) efficiency and its influencing factors of maize production in China during 1998–2010. WU and productivity (WP) were quantified by taking irrigation loss into account and the links between WP and nine selected indicators were revealed by the partial least squares regression (PLSR) model. Results showed that national WU and WP in maize production were 138.56 cubic gigametres (Gm3; 0.755 green and 0.245 blue) and 1.079 kg/m3, respectively. WP was enhanced in the present study due to an increase in irrigated crop yield. Provinces located in the middle–lower part of the Yellow River had high proportions of green water and WP, while high proportions of irrigation water and low WP were found in Northwest China. The dosage of pesticides per unit area, relative humidity, average temperature and precipitation were the dominant factors that affected WP. However, the relationships between WP and solar radiation, fertilizer, agricultural machinery power, irrigation proportion and irrigated efficiency were not significant. Findings of the present research may also provide a reference for regional agricultural water management.
Previous studies showed that spermine could protect the organism from oxidative damage in vivo. However, in vivo information on the antioxidant-related underlying molecular mechanism of spermine is limited. In this experiment, we further evaluated the effects of spermine supplementation and extended spermine administration on the antioxidant status and antioxidant-related signaling molecules gene expression in the liver and longissimus dorsi of piglets. A total of 80 piglets were randomly distributed to two groups, that is, those with adequate nutrient intake administrated with spermine (0.4 mmol/kg BW) or those with restricted nutrient intake supplemented by saline. The piglets were fed in pairs for 7 h or 3, 6, or 9 days. The results are as follows: (1) spermine can promote the antioxidant capacity by increasing enzymatic antioxidant capacity, glutathione content and clearance of oxygen radicals; (2) spermine significantly increased the mRNA levels of enzymatic antioxidant substances, NF-E2-related nuclear factor 2, Kelch-like ECH-associated protein 1, and the mammalian target of rapamycin but decreased the mRNA levels of ribosomal p70 S6 kinase in the liver and longissimus dorsi of the piglets.
Here a compact three orthogonal planes high-energy electron radiography system was proposed. One of the critical technologies, the ultra-fast beam bunches split from the bunch train are studied. The separated bunches could be transported to the three orthogonal planes of the target for dynamic radiography diagnostics. The key elements of the ultra-fast bunches split system are transverse deflecting cavity (TDC) and the twin septum magnet (TSM). The principle of TDC and TSM are briefly introduced. An example of the beam bunches split system for test experiment (40 MeV electron beam) with TDC and TSM is designed and studied by particle-tracking simulation and it confirms this method is valid and feasible. Especially with TSM, a compact three orthogonal planes radiography system can be realized. The evolution of the beam parameters along the beam line from simulation are investigated. The detailed design of the beam split system and beam dynamics simulation study are presented in this paper.
We studied the evolution, genotypes, and the molecular clock of dengue virus serotype 1 (DENV-1), between 2001 and 2014 in Guangzhou, China. The analysis of the envelope (E) gene sequences of 67 DENV-1 strains isolated in Guangzhou, together with 58 representative sequences downloaded from NCBI, have shown shifts in viral genotypes. The genotype changed several times, from genotype I to IV in 2002, from IV to I in 2005, and from I to V in 2014. These genotype shifts may be the cause of DENV outbreaks. The diversity of genotypes and clades demonstrates a high risk of future outbreaks in Guangzhou. The mean rate of virus nucleotide substitution in Guangzhou was determined to be 7·77 × 10−4 per site per year, which represents a medium substitution rate compared to two other countries. Our research can point to different ancestors of the isolated strains, which may further reveal the different origins and transmission of DENV-1 strains in Guangzhou.
The oriental fruit moth (OFM) Grapholita molesta (Lepidoptera: Tortricidae) is an important economic pest of stone and pome fruits worldwide. We sequenced the OFM genome using next-generation sequencing and characterized the microsatellite distribution. In total, 56,674 microsatellites were identified, with 11,584 loci suitable for primer design. Twenty-seven polymorphic microsatellites, including 24 loci with trinucleotide repeat and three with pentanucleotide repeat, were validated in 95 individuals from four natural populations. The allele numbers ranged from 4 to 40, with an average value of 13.7 per locus. A high frequency of null alleles was observed in most loci developed for the OFM. Three marker panels, all of the loci, nine loci with the lowest null allele frequencies, and nine loci with the highest null allele frequencies, were established for population genetics analyses. The null allele influenced estimations of genetic diversity parameters but not the OFM's genetic structure. Both a STRUCTURE analysis and a discriminant analysis of principal components, using the three marker panels, divided the four natural populations into three groups. However, more individuals were incorrectly assigned by the STRUCTURE analysis when the marker panel with the highest null allele frequency was used compared with the other two panels. Our study provides empirical research on the effects of null alleles on population genetics analyses. The microsatellites developed will be valuable markers for genetic studies of the OFM.
We present a scheme of electron beam radiography to dynamically diagnose the high energy density (HED) matter in three orthogonal directions simultaneously based on electron Linear Accelerator. The dynamic target information such as, its profile and density could be obtained through imaging the scattered electron beam passing through the target. Using an electron bunch train with flexible time structure, a very high temporal evolution could be achieved. In this proposed scheme, it is possible to obtain 1010 frames/second in one experimental event, and the temporal resolution can go up to 1 ps, spatial resolution to 1 µm. Successful demonstration of this concept will have a major impact for both future inertial confinement fusion science and HED physics research.