| 1. |
- Ma, Tao, et al.
(författare)
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Genomic insights into salt adaptation in a desert poplar
- 2013
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4, s. 2797-
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Tidskriftsartikel (refereegranskat)abstract
- Despite the high economic and ecological importance of forests, our knowledge of the genomic evolution of trees under salt stress remains very limited. Here we report the genome sequence of the desert poplar, Populus euphratica, which exhibits high tolerance to salt stress. Its genome is very similar and collinear to that of the closely related mesophytic congener, P. trichocarpa. However, we find that several gene families likely to be involved in tolerance to salt stress contain significantly more gene copies within the P. euphratica lineage. Furthermore, genes showing evidence of positive selection are significantly enriched in functional categories related to salt stress. Some of these genes, and others within the same categories, are significantly upregulated under salt stress relative to their expression in another salt-sensitive poplar. Our results provide an important background for understanding tree adaptation to salt stress and facilitating the genetic improvement of cultivated poplars for saline soils.
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| 2. |
- Wang, Cao, et al.
(författare)
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Microstructure homogeneity control in spark plasma sintering of Al2O3 ceramics
- 2010
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 31:1-2, s. 231-235
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous microstructure control in the SPS (spark plasma sintering) sintered big size Al2O3 ceramic was realized by the synergy effect of grain boundary tailoring and proper pressure profile design. Two-step pressure profile itself did not show any efficient densification enhancement if no grain boundary modifier MgO added. The two-step pressure profile can effectively reduce average grain size and grain size difference over the sintered specimen, while MgO doping can reduce the average grain size in the whole sintered samples. Finally, a general strategy to overcome the intrinsic temperature gradient in SPS is suggested.
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| 3. |
- Zhe, XW, et al.
(författare)
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Hypertriglyceridemic waist is associated with increased carotid atherosclerosis in chronic kidney disease patients
- 2012
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Ingår i: Nephron. Clinical practice. - : S. Karger AG. - 1660-2110. ; 122:3-4, s. 146-152
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Patients with chronic kidney disease (CKD) have an unacceptably high risk of death, primarily as a result of cardiovascular disease (CVD). The ‘hypertriglyceridemic waist' phenotype has been proposed as a simple and strong predictor of CVD risk. Therefore, we investigated the relationship between the hypertriglyceridemic waist phenotype and carotid atherosclerosis in CKD patients. <b><i>Methods:</i></b> In a cross-sectional study, we enrolled 785 prevalent CKD patients [416 males, aged 44.6 years (21.7-69.4), glomerular filtration rate 52.5 ml/min/1.73 m<sup>2</sup> (5.3-119.4)]. We divided the patients into three groups: group 1: waist circumference >90 cm in men or >85 cm in women and triglycerides ≥2 mmol/l (n = 109); group 3: waist circumference ≤90 cm in men or ≤85 cm in women and triglycerides <2 mmol/l (n = 379), and group 2: the remaining patients (n = 297). Routine biochemical parameters and carotid artery intima-media thickness (IMT) were measured. <b><i>Results:</i></b> The prevalence of the hypertriglyceridemic waist phenotypes was 13.8% in the CKD patients. Triglyceride, total cholesterol, HDL-cholesterol and LDL-cholesterol concentrations in group 1 were significantly higher than those in group 3. Carotid artery IMT of the hypertriglyceridemic waist group was the highest. <b><i>Conclusion:</i></b> The hypertriglyceridemic waist phenotype was associated with worse carotid atherosclerosis in CKD patients. This suggests that the hypertriglyceridemic waist phenotype may be useful for predicting CVD risk in CKD patients.
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| 5. |
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| 6. |
- Gao, Feng, et al.
(författare)
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Trap-Induced Losses in Hybrid Photovoltaics
- 2014
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 8:4, s. 3213-3221
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the loss mechanisms in hybrid photovoltaics based on blends of poly(3-hexylthiophene) with CdSe nanocrystals of various sizes. By combining the spectroscopic and electrical measurements on working devices as well as films, we identify that high trap-mediated recombination is responsible for the loss of photogenerated charge carriers in devices with small nanocrystals. In addition, we demonstrate that the reduced open-circuit voltage for devices with small nanocrystals is also caused by the traps.
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| 7. |
- Liang, Lijun, et al.
(författare)
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Theoretical studies on the dynamics of DNA fragment translocation through multilayer graphene nanopores
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:92, s. 50494-50502
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by several potential advantages over common sequencing technologies, solid-state nanopores, in particular graphene nanopores, have recently been extensively explored as biosensor materials for DNA sequencing. Studies carried out on monolayer graphene nanopores aiming at single-base resolution have recently been extended to multilayer graphene (MLG) films, indicating that MLG nanopores are superior to their monolayer counterparts for DNA sequencing. However, the underlying dynamics and current change in the DNA translocation to thread MLG nanopores remain poorly understood. In this paper, we report a molecular dynamics study of DNA passing through graphene nanopores of different layers. We show that the DNA translocation time could be extended by increasing the graphene layers up to a moderate number (7) under a high electric field and that the current in DNA translocation undergoes a stepwise change upon DNA going through an MLG nanopore. A model is built to account for the relationship between the current change and the unoccupied volume of the MLG nanopore. We demonstrate that the dynamics of DNA translocation depends specifically on the interaction of nucleotides with the graphene sheet. Thus, our study indicates that the resolution of DNA detection could be improved by increasing the number of graphene layers in a certain range and by modifying the surface of the graphene nanopores.
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| 8. |
- Prakash, G. K. Surya, et al.
(författare)
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Long-Lived Trifluoromethanide Anion: A Key Intermediate in Nucleophilic Trifluoromethylations.
- 2014
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 53:43, s. 11575-11578
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Tidskriftsartikel (refereegranskat)abstract
- The trifluoromethanide anion is the postulated key intermediate in nucleophilic trifluoromethylation reactions. However, for more than six decades, the trifluoromethanide anion was widely believed to exist only as a short-lived transient species in the condensed phase. It has now been prepd. in bulk for the first time in THF soln. The trifluoromethanide anion with the [K(18-crown-6)]+ cation was unequivocally characterized by low-temp. 19F and 13C NMR spectroscopy. Its intermediacy in nucleophilic trifluoromethylation reactions was directly evident by its reaction chem. with various electrophilic substrates. Variable-temp. NMR spectroscopy, along with quantum mech. calcns., support the persistence of the trifluoromethanide anion. [on SciFinder(R)]
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| 9. |
- Prakash, G. K. Surya, et al.
(författare)
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The Trifluoromethyl Group as a Conformational Stabilizer and Probe: Conformational Analysis of Cinchona Alkaloid Scaffolds.
- 2014
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 136:29, s. 10418-10431
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of the CF3 group on the C9 atom in quinidine can significantly increase the conformational interconversion barrier of the cinchona alkaloid scaffold. With this modification the conformational behavior of cinchona alkaloids in various solvents can be conveniently studied via 19F NMR spectroscopy. Based on the reliable conformational distribution information obtained, the accuracy of both theor. (PCM) and empirical (Kamlet-Taft) solvation models was assessed using linear free energy relation methods. The empirical solvation model provides accurate prediction of solvent effects, while PCM demonstrated a relatively low reliability. Using similar empirical solvation models along with Karplus-type equations, the conformational behavior of quinidine and 9-epi-quinidine also was studied. A model SN2 reaction was presented to reveal the important role of solvent-induced conformational behavior of cinchona alkaloids in their reactivity. [on SciFinder(R)]
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| 10. |
- Wang, Cao, et al.
(författare)
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FEM analysis of the temperature and stress distribution in spark plasma sintering : Modelling and experimental validation
- 2010
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Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 49:2, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- A fully thermal-electrical-mechanical coupled and dynamic finite element model (FEM) is implemented to analyze of the temperature and stress distribution in spark plasma sintering (SPS) process. The real densification behaviour is also integrated by the moving mesh technique. The simulation studies were conducted using COMSOL and a range of die sizes, heating rates and uniaxial stresses were considered. The further validation experiments are implemented to validate the simulation results. The detailed microstructure investigations generally demonstrate that the temperature and stress profile obtained in present model are correct. But further development of complicated models is still needed for more precise prediction of sintering condition and microstructure development in SPS.
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