| 21. |
- Yang, Liping
(författare)
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Cellular and Molecular Pathways Governing Hematopoietic Stem Cell Fate
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hematopoietic Stem Cells (HSCs) have been defined to have abilities of both self-renewal and multi-lineage differen-tiation. The balance between these abilities is rigorously controlled under steady-state status (homeostasis) and when the normal processes of self-renewal and differentiation become deregulated, a disorder of blood system (such as leukemias) can occur. HSCs are enriched in lineage negative (Lin-), SCA-1 positive and c-KIT positive (LSK) cells in mouse bone marrow (BM), as well as in the Lin(-)CD34(+) cells in human BM or cord blood. However, the LSK compartment is heterogeneous, containing long-term (LT) and short-term (ST) self-renewing HSCs as well as non-self-renewing multipotent progen-itors (MPPs) and demanding further subfractionation of this population to allow for detailed functional investiga-tions. Even though these different subpopulations are phenotypically and functionally characterized, it is still poorly understood how LT-HSCs make a cell fate decision to differentiate into ST-HSCs and further to MPPs, as well as how the cellular and molecular pathways regulate HSC fate decisions. In this thesis, we identified two distinct subpopulations within BM and fetal liver LSK compartment: ST-HSC population identified as LSKCD34(+/hi)FLT3(-) cells and lymphoid primed multipotent progenitors (termed LMPPs) represented by LSKCD34(+)FLT3(hi) cells. LSKCD34(+/hi)FLT3(-) cells are capable of rapid but short-term reconstitution, high colony-forming units-spleen (CFU-S) and radio-protective activities while LSKCD34(+)FLT3(hi) cells can give rise to lymphoid and myeloid cells but have no self-renewal activity and little or no megakaryocytic-erythrocytic (MkE) potentials. This was further supported by gene expression analysis revealing a modulation of genetic programs in the transition from the ST-HSC to the LMPP, with down-regulation of MkE and up-regulation of lymphoid gene programs. The work has also investigated the regulatory roles of extrinsic modulators on HSC function. We found that HSC self-renewal is negatively regulated by activation of the IFN-gamma and Fas pathways, through the promotion of HSC differentiation.
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| 22. |
- Yang, Liping, et al.
(författare)
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Effects of fat, beef and fiber in diets on activities of sphingomyelinase, ceramidase and caspase-3 in rat colonic mucosa
- 2002
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Ingår i: Medical Principles and Practice. - : S. Karger AG. - 1011-7571 .- 1423-0151. ; 11:3, s. 150-156
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The present study investigates the activity changes of sphingomyelinase (SMase), ceramidase and caspase-3 in colonic mucosa of rats induced by high fat and red meat diets. Method. For a period of 3 weeks, rats were fed protein without fat (control), high fat only, high fat with beef, and high fat with fiber (cellulose) diets. The fat content (22.4%) was constant in the three high fat diets. Then, the colonic mucosae were scraped and homogenized and the activities of SMase, ceramidase and caspase-3 determined. Results: Compared to the control diet, the fat diet and fat with beef diet reduced intestinal alkaline SMase by 80 and 84%, respectively; ceramidase activity by 60 and 92%, respectively, and caspase-3 activity by 40 and 75%, respectively. The activities of acid and neutral SMases were also decreased by fat and fat with beef diets but to a smaller extent than those of alkaline SMase. Supplement of fiber in the fat diet had no effect on the changes of alkaline SMase activity but prevented fat-induced decreases in acid and neutral SMase activities and partially prevented those of ceramidase and caspase-3 activities. The activity of intestinal alkaline phosphatase was not changed by any of the diets. Conclusion: Fat, beef and fiber significantly affect the enzymes responsible for sphingomyelin metabolism and apoptosis in the colon. The effects may have implications in colonic tumorigenesis related to dietary factors.
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| 23. |
- Yang, Liping, et al.
(författare)
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Effects of red meat and fiber in high fat diet on activities of sphingomyelinase, ceramidase and caspase-3 in rat colonic mucosa.
- 2002
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Ingår i: Journal of Nutritional Biochemistry. - 1873-4847. ; 13:8, s. 499-504
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Tidskriftsartikel (refereegranskat)abstract
- Red meat and fiber rich foods are the dietary factors most consistently related to colon carcinogenesis. Although several components in these dietary sources may contribute, the biochemical mechanism by which red meat and fiber affect colorectal carcinogenesis has not yet been established. Sphingomyelin metabolism is a novel signal transduction pathway that may have an impact on colonic tumorigenesis. The present study investigated the activity changes of sphingomyelinase (SMase), ceramidase and caspase-3 in colonic mucosa of rats fed on a high fat control diet, the control diet with beef and the control diet with fiber (cellulose). After a three week feeding period the colonic mucosa were scraped and homogenized and enzyme activities were determined. The fiber diet significantly increased the activities of neutral and acid SMases but had no effect on those of alkaline SMase and neutral ceramidase. The beef diet, on the other hand, significantly reduced neutral ceramidase activity, but had no effect on the activities of any SMase. In addition, the beef diet significantly reduced and the fiber diet increased caspase-3 activity in the colonic mucosa when compared with the control diet. The changes of caspase-3 activities were abolished by preincubating the samples with caspase-3 inhibitor. No significant changes of intestinal alkaline phosphatase could be found among the three dietary groups. In conclusion, fiber and red meat in the high fat diet affected in an opposite way the enzymes responsible for sphingomyelin metabolism and apoptosis in the colon. The effects may have implications in colorectal tumorigenesis.
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| 24. |
- Yang, Liping, et al.
(författare)
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Identification of Lin(-)Sca1(+)kit(+)CD34(+)Flt3- short-term hematopoietic stem cells capable of rapidly reconstituting and rescuing myeloablated transplant recipients
- 2005
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Ingår i: Blood. - Washington : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 105:7, s. 2717-2723
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Tidskriftsartikel (refereegranskat)abstract
- In clinical bone marrow transplantation, the severe cytopenias induced by bone marrow ablation translate into high risks of developing fatal infections and bleedings, until transplanted hematopoietic stem and progenitor cells have replaced sufficient myeloerythroid offspring. Although adult long-term hematopoietic stem cells (LT-HSCs) are absolutely required and at the single-cell level sufficient for sustained reconstitution of all blood cell lineages, they have been suggested to be less efficient at rapidly reconstituting the hematopoietic system and rescuing myeloablated recipients. Such a function has been proposed to rather be mediated by less well-defined short-term hematopoietic stem cells (ST-HSCs). Herein, we demonstrate that Lin(-)Sca1(+)kit(hi)CD34+ short-term reconstituting cells contain 2 phenotypically and functionally distinct subpopulations: Lin(-)Sca1(+)kit(hi)CD34(+)flt3- cells fulfilling all criteria of ST-HSCs, capable of rapidly reconstituting myelopoiesis, rescuing myeloablated mice, and generating Lin(-)Sca1(+)kit(hi)CD34(+)flt3+ cells, responsible primarily for rapid lymphoid reconstitution. Representing the first commitment steps from Lin(-)Sca1(+)kit(hi) CD34(-)flt3- LT-HSCs, their identification will greatly facilitate delineation of regulatory pathways controlling HSC fate decisions and identification of human ST-HSCs responsible for rapid reconstitution following HSC transplantations.
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| 25. |
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| 26. |
- Yang, Shujuan, et al.
(författare)
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Enhanced permeability, mechanical and antibacterial properties of cellulose acetate ultrafiltration membranes incorporated with lignocellulose nanofibrils
- 2020
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Ingår i: International Journal of Biological Macromolecules. - : ELSEVIER. - 0141-8130 .- 1879-0003. ; 151, s. 159-167
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose acetate (CA) ultrafiltration membranes are attracting more attention in wastewater purification due to its biodegradability and eco-friendly. The application of CA membranes, however, is limited by high susceptibility to bacterial corrosion and lack of mechanical tolerance that results in loss of life. To solve the above problems, we first fabricated the CA-based composite membranes incorporated with bamboo-based lignocellulose nanofibrils (LCNFs) by a strategy of phase inversion. LCNFs was prepared by using a combined method of one-step chemical pretreatment and add hydrolysis coupled with high-pressure homogenization. The as-prepared CA/LCNFs composite membranes with 4 wt% lignin in the LCNFs exhibited high tensile strength of 7.08 MPa and strain-at-break of 12.21%, and high filtration permeability of 188.23 L. m(-2).h(-1) as ultrafiltration membranes for wastewater treatment, which could obviously inhibit the growth of Escherichia Coli.
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| 27. |
- Yao, Lei, et al.
(författare)
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Atmospheric new particle formation from sulfuric acid and amines in a Chinese megacity
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 361:6399, s. 278-281
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric new particle formation (NPF) is an important global phenomenon that is nevertheless sensitive to ambient conditions. According to both observation and theoretical arguments, NPF usually requires a relatively high sulfuric acid (H2SO4) concentration to promote the formation of new particles and a low preexisting aerosol loading to minimize the sink of new particles. We investigated NPF in Shanghai and were able to observe both precursor vapors (H2SO4) and initial clusters at a molecular level in a megacity. High NPF rates were observed to coincide with several familiar markers suggestive of H2SO4-dimethylamine (DMA)water (H2O) nucleation, including sulfuric acid dimers and H2SO4-DMA clusters. In a cluster kinetics simulation, the observed concentration of sulfuric acid was high enough to explain the particle growth to similar to 3 nanometers under the very high condensation sink, whereas the subsequent higher growth rate beyond this size is believed to result fromthe added contribution of condensing organic species. These findings will help in understanding urban NPF and its air quality and climate effects, as well as in formulating policies to mitigate secondary particle formation in China.
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| 28. |
- You, Fang, et al.
(författare)
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Icon Design Recommendations for Central Consoles of Intelligent Vehicles
- 2020
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Ingår i: Human Interaction, Emerging Technologies and Future Applications II. - Cham : Springer. - 9783030442668 - 9783030442675 ; , s. 285-291
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Konferensbidrag (refereegranskat)abstract
- Advances in vehicle technology open up both opportunities and challenges for human-machine interface (HMI) design in intelligent vehicles. Design guidelines for icons in central consoles of vehicles have been discussed in human-computer interaction community, but more study and innovation are needed in icon design. In this paper, we investigated the displayed line thickness and size of icons in the intelligent vehicle’s central control screen, based on international design guidelines and standards. The experiment involved 17 participants performing simulated in-vehicle secondary task. The result from the experiments shows that the usability of icons increases and the driver’s workload decreases as the icons get larger. We also found a set of recommended values for size and line thickness of icons in this context. Future work will focus on providing design guidelines for other aspects of HMI design in intelligent vehicles.
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| 29. |
- You, Fang, et al.
(författare)
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Interface Color Design of Intelligent Vehicle Central Console
- 2021
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Ingår i: Advances in Usability, User Experience, Wearable and Assistive Technology. - Cham : Springer Nature. - 9783030800901 - 9783030800918 ; , s. 784-792
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Konferensbidrag (refereegranskat)abstract
- The development of intelligent automobiles puts forward higher requirements for HMI design. The information obtained by drivers through vision accounts for 80%. As a key part of visual perception, color affects driving performance. This article investigates vehicle interface design about icon-background contrast. Three colors commonly used in car-machine interface are chosen: red, green and blue, and contrast is divided into five levels under daytime and nighttime. The participants tested three colors and the five contrasts in an experiment using classic paradigm of secondary tasks. We collected data from their driving behavior and subjective experience, trying to find a most appropriate value. The results show that recommended contrast values under different lighting conditions are 3:1 to 4:1 for red, blue, and green during the day; 3:1 for red at night, and 5:1 for blue and green, so that the vehicle central console color design references are formed.
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| 30. |
- Zhang, Fan, et al.
(författare)
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Proliferative and Survival Effects of PUMA Promote Angiogenesis
- 2012
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Ingår i: Cell Reports. - : Elsevier (Cell Press). - 2211-1247. ; 2:5, s. 1272-1285
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Tidskriftsartikel (refereegranskat)abstract
- The p53 upregulated modulator of apoptosis (PUMA) is known as an essential apoptosis inducer. Here, we report the seemingly paradoxical finding that PUMA is a proangiogenic factor critically required for the proliferation and survival of vascular and microglia cells. Strikingly, Puma deficiency by genetic deletion or small hairpin RNA knockdown inhibited developmental and pathological angiogenesis and reduced microglia numbers in vivo, whereas Puma gene delivery increased angiogenesis and cell survival. Mechanistically, we revealed that PUMA plays a critical role in regulating autophagy by modulating Erk activation and intracellular calcium level. Our findings revealed an unexpected function of PUMA in promoting angiogenesis and warrant more careful investigations into the therapeutic potential of PUMA in treating cancer and degenerative diseases.
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