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Diesel engines are widely used for propulsion on large ships, which has the undesired characteristic of generating large amounts of harmful emissions. To reduce these emissions, some alternative fuel was developed and used in a marine diesel engine. In this study, an experiment was carried out on a 6-cylinder turbocharged direct-injection marine diesel propulsion engine. A small proportion blend of biodiesel-diesel was used, aimed at exploring the emission characteristics and emission reduction mechanism for diesel propulsion engines. The results show that the high oxygen content of biodiesel blend is crucial for inhibiting the formation of particulate matter (PM) and reducing the formation of total unburned hydrocarbon (THC) and carbon monoxide (CO), which reduces the emission of harmful gases. At the same time, the number of particles (PN) has also decreased. However, the rapid burn rate of biodiesel was found to reduce brake thermal efficiency (BTE), resulting in an increase of fuel consumption and exhaust gas temperature (EGT), which can promote the formation of nitrogen oxides (NOx). More carbon dioxide (CO2) is released due to the increased fuel consumption. The emission characteristics of the biodiesel blend and diesel fuel are discussed in this work.
Background: Platelet derived growth factors (PDGFs) are key components of autocrine and paracrine signalling, both of which play important roles in mammalian developmental processes. PDGF expression levels also relate to oxygen levels. The characteristics of yak PDGFs, which are indigenous to hypoxic environments, have not been clearly described until the current study. Materials and methods: We amplified the open reading frame encoding yak (Bos grunniens) platelet derived growth factor-alpha (PDGFA) from a yak skin tissue cDNA library by reverse transcriptase polymerase chain reaction (PCR) using specific primers and Sanger dideoxy sequencing. Expression of PDGFA mRNA in different portions of yak brain tissue (cerebrum, cerebellum, hippocampus, and spinal cord) was detected by quantitative real-time PCR (qRT-PCR). PDGFA protein expression levels and its location in different portions of the yak brain were evaluated by western blot and immunohistochemistry. Results: We obtained a yak PDGFA 755 bp cDNA gene fragment containing a 636 bp open reading frame, encoding 211 amino acids (GenBank: KU851801). Phylogenetic analysis shows yak PDGFA to be well conserved, having 98.1% DNA sequence identity to homologous Bubalus bubalus and Bos taurus PDGFA genes. However, 8 nucleotides in the yak DNA sequence and 4 amino acids in the yak protein sequence differ from the other two species. PDGFA is widely expressed in yak brain tissue, and furthermore, PDGFA expression in the cerebrum and cerebellum are higher than in the hippocampus and spinal cord (p > 0.05). PDGFA was observed by immunohistochemistry in glial cells of the cerebrum, cerebellum, and hippocampus, as well as in pyramidal cells of the cerebrum, and Purkinje cell bodies of the hippocampus, but not in glial cells of the spinal cord. Conclusions: The PDGFA gene is well conserved in the animal kingdom; however, the yak PDGFA gene has unique characteristics and brain expression patterns specific to this high elevation species. (Folia Morphol 2017; 76, 4: 551–557)
Water inrush during the excavation of mines or mining is one of the great challenges in underground engineering work in China. To prevent and/or mitigate water inrush, natural sedimentary rocks with low-permeability, which include the mudstone and sandstone found in underground excavations, are exceptional materials for geological barriers. The aim of this work is to therefore investigate the hydraulic properties of sedimentary rocks in a deep tunnel, with the application of high-pressure packer tests (HPPTs). The experimental results indicate that both the mudstone and sandstone are low permeability. The measured injection pressure-flow rate (P-Q) can be divided into two phases: Phase I – a flow that is Darcian with a linear relationship, and Phase II – changes in the flow pattern with an exponential relationship. Water injection primarily triggers fracture dilation, and then results in an evident increase in hydraulic conductivity. The hydraulic conductivity versus water pressure distribution phase can be considered as three flow phases: the initial flow phase, initiation of flow communication phase, and non-steady state flow phase. The calculated original fracture apertures in mudstone and sandstone are, respectively, 0.37 and 0.33 mm. Furthermore, a conceptual model with two phases of fracture aperture versus water pressure is proposed.
C-repeat binding factor (CBF) signaling pathway is involved in cold acclimation responsive to low temperature and some other stresses. CBF transcription factor family is the key component of this pathway. In this study, eight CBF-like genes, BrCBF1, BrCBF2, BrCBF3, BrCBF4, BrCBF5, and BrCBF6A/B/C were isolated from non-heading Chinese cabbage (Brassica campestris ssp. chinensis L. Makino, NHCC). The deduced CBF proteins shared high similarity with their Arabidopsis orthologs and localized to the nucleus. Furthermore, quantitative realtime PCR (qPCR) analysis showed that BrCBF1~3 were induced by cold (4 C) but not drought or abscisic acid (ABA), indicating that they are involved in an ABA-independent pathway; however, BrCBF4~6 were regulated by both drought and ABA, suggesting that they were involved in an ABA-dependent pathway. Nevertheless, unlike Arabidopsis, BrCBF4~6 showed response to both cold and ABA, indicates ABA-independent and ABA-dependent parts of CBF pathway in NHCC might not be completely separate, and these genes may act as the connection points in the network. BrCBFs were also accumulated in response to salicylic acid (SA), methyljasmonate (MeJA), and ethylene (ET), indicating that BrCBF genes might participate in the response to biotic stresses. Taken together, eight CBF genes were isolated from NHCC which compose a functional CBF signaling pathway by participating in response to multiple stresses and performing roles from Arabidopsis to some extent.
Extensive genetic variations of low-molecular-weight glutenin subunits (LMW-GS) and their coding genes were found in the wild diploid A- and D-genome donors of common wheat. In this study, we reported the isolation and characterization of 8 novel LMW-GS genes from Ae.longissima Schweinf. & Muschl., a species of the section Sitopsis of the genus Aegilops, which is closely related to the В genome of common wheat. Based on the N-terminal domain sequences, the 8 genes were divided into 3 groups. A consensus alignment of the extremely conserved domains with known gene groups and the subsequent cluster analysis showed that 2 out of the 3 groups of LMW-GS genes were closely related to those from the В genome, and the remaining was related to those from A and D genomes of wheat and Ae. tauschii. Using 3 sets of gene-group-specific primers, PCRs in diploid, tetraploid and hexaploid wheats and Ae. tauschii failed to obtain the expected products, indicating that the 3 groups of LMW-GS genes obtained in this study were new members of LMW-GS multi-gene famailies. These results suggested that the Sitopsis species of the genus Aegilops with novel gene variations could be used as valuable gene resources of LMW-GS. The 3 sets of group-specific primers could be utilized as molecular markers to investigate the introgression of novel alien LMW-GS genes from Ae. longissima into wheat.
Chilling stress has a strong negative impact on the growth and development of winter wheat (Triticum aestivum L.). To investigate the recovery of physiological function and yield formation by plant growth regulators following chilling stress, we performed low-temperature phytotron experiments at the booting stage, and sprayed 6-benzylamino adenine (6-BA), salicylic acid (SA), brassinolide (BR) and abscisic acid (ABA) after chilling stress. Plant growth regulators significantly enhanced SPAD value and net photosynthetic rate (Pn) in flag leaves following chilling stress (p < 0.05). Compared with the control group sprayed with distilled water, stomatal conductance (Gs) and transpiration rate (Tr) increased, while intercellular carbon dioxide concentration (Ci) decreased. In addition, the concentration of malondialdehyde (MDA) was significantly decreased, and the activities of superoxide dismutase (SOD) and peroxidase (POD) were enhanced (p < 0.05). Plant growth regulators also increased the grain filling rate during the 14 days after anthesis, thereby increasing grain weight. The grain number per spike, 1000-kernel weight, and yield per plant after harvest were also significantly enhanced (p < 0.05). Thus, spraying plant growth regulators at the booting stage relieved the adverse effects on physiological activity in wheat flag leaves caused by chilling stress, and 6-BA and SA were particularly effective.
The objective of this study was to evaluate the effect of different fiber sources on jejunal digestive and absorptive physiology in weaned piglets. One hundred weaned piglets were allotted according to body weight, gender and litter to four dietary treatments. Each treatment was replicated in 5 pens of 5 pigs each. The experimental diets contained 10% of a fiber source: wheat bran (WB), maize fiber (MF), soyabean fiber (SF), or pea fiber (PF). Piglets were fed ad libitum for 30 d. Reduced villus height and villus height-to-crypt depth ratio (P < 0.05) were observed in pigs fed diet MF compared with pigs fed diet WB. In the mid-jejunal mucosa, lower activities of sucrase (P < 0.05) were found in pigs fed diets MF and SF compared with WB. In mid-jejunal digesta, inclusion of SF and PF decreased the activities of trypsin and lipase (P < 0.05) compared with inclusion of WB. Supplementation with PF resulted in higher facilitated glucose transporter 2 (P < 0.05) and lower excitatory amino acid carrier 1 mRNA levels compared with supplementing WB. The apparent faecal digestibility of gross energy, dry matter, organic matter, neutral detergent fiber and acid detergent fiber declined in the following order: diet SF > PF > MF > WB. Our study indicates that SF and PF could promote apparent faecal digestibility in piglets, but this is not accompanied by better jejunal morphology or digestive enzyme activities as compared with WB.
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