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1.
Under normal physiological conditions the brain primarily utilizes glucose for ATP generation. However, in situations where glucose is sparse, e.g., during prolonged fasting, ketone bodies become an important energy source for the brain. The brain’s utilization of ketones seems to depend mainly on the concentration in the blood, thus many dietary approaches such as ketogenic diets, ingestion of ketogenic medium-chain fatty acids or exogenous ketones, facilitate significant changes in the brain’s metabolism. Therefore, these approaches may ameliorate the energy crisis in neurodegenerative diseases, which are characterized by a deterioration of the brain’s glucose metabolism, providing a therapeutic advantage in these diseases. Most clinical studies examining the neuroprotective role of ketone bodies have been conducted in patients with Alzheimer’s disease, where brain imaging studies support the notion of enhancing brain energy metabolism with ketones. Likewise, a few studies show modest functional improvements in patients with Parkinson’s disease and cognitive benefits in patients with—or at risk of—Alzheimer’s disease after ketogenic interventions. Here, we summarize current knowledge on how ketogenic interventions support brain metabolism and discuss the therapeutic role of ketones in neurodegenerative disease, emphasizing clinical data.  相似文献   
2.
Shift in thinking to address the 21st century hunger gap   总被引:1,自引:1,他引:0  
The present water policy debate is dominated by the 30 yr old mission to secure water supply and sanitation to all people. The water needed to produce a nutritionally acceptable diet for one person is however 70 times as large as the amount needed for domestic water supply. The food security dilemma is largest in arid climate regions, a situation constituting a formidable challenge. It is suggested that an additional 5 600 km3/yr of consumptive water use will be needed to produce an adequate amount of food by 2050 – i.e almost a doubling of today’s consumptive use of 6800 km3/yr. Past misinterpretations and conceptual deficiencies show the importance of a shift in thinking. Combining the scale of the challenge and the time scale of the efforts to feed humanity and eradicate hunger leads to an impression of great urgency. This urgency strengthens the call for international research both for supporting agricultural upgrading, and for much better handling of issues of environmental sustainability. What stands out is the need of a new generation of water professionals, able to handle complexity and able to incorporate water implications of land use and of ecosystem health in integrated water resources management. It will for those reasons be essential and urgent to upgrade the educational system to producing this new generation.  相似文献   
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The Al2O3–SiO2 system has been reassessed using a solution model for mullite extending from sillimanite to a hypothetical state of alumina. The property of sillimanite, to be used to describe one of the end-members, was extracted from an analysis of the T – P phase diagram for Al2SiO5 polymorphs. It was possible to represent the information on the range of stability of mullite, including some showing that mullite extends to higher SiO2 contents than represented by the composition of 3:2 mullite. An attempt was made to model the liquid with the ionic two-sublattice model using a new species AlO2−1. The pressure dependence of Al2SiO5 polymorphs was optimized by a new model recently implemented in Thermo-Calc.  相似文献   
5.
To successfully manage today’s complex production systems it is essential to study operators’ perception of the system. The paper presents perceived production complexity assessed at seven manufacturing companies with the CompleXity Index (CXI) method. While other methods have measured product variants, layout, work content, tools and information items, CXI combines them into three areas. These three complexity areas (Station design, Work variance and Disturbance handling) help to create an understanding of the complex system by visualising how they contribute to complexity, and show the need to support the operators’ ability to handle the varying work.  相似文献   
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Recent studies have applied Grottfredson and Hirschi’s General Theory of Crime to investigate whether college students’ inclinations toward internet software piracy is related to low self-control and opportunity (i.e., computer ownership). Given the widespread use of the internet to illegally obtain copies of music and movies, it is important to understand the factors in this form of piracy as well. This study applied the self-control perspective to examine the attitudes of high school students toward the internet piracy of music and movies. Attitudes toward the internet piracy of music and movies were related to self-control, biological sex, internet experience, affiliation with deviant peers, and grade level in this study of high school students. This information is important because studies of internet piracy had not yet confirmed the presence and predictability of internet piracy in high school students. This study also suggests that piracy prevention efforts may be most appropriately focused on high school age individuals and directed toward increasing self-control.  相似文献   
8.
The aim of this review is to provide an overview of proteomic studies in animal models of diabetes and to give some insight into the different methods available today in the rapidly developing field of proteomics. A summary of 31 papers published between 1997 and 2007 is presented. For instance, proteomics has been used to study the development of both type 1 and type 2 diabetes, diabetic complications in tissues like heart, kidney and retina and changes after treatment with anti-diabetic drugs like peroxisome proliferator-activated receptors agonists. Together, these studies give a good overview of a number of experimental approaches. Proteomics holds the promise of providing major contributions to the field of diabetes research. However, to achieve this, a number of issues need to be resolved. Appropriate data representation to facilitate data comparison, exchange, and verification is required, as well as improved statistical assessment of proteomic experiments. In addition, it is important to follow up the results with functional studies to be able to make biologically relevant conclusions. The potential of proteomics to dissect complex human disorders is now beginning to be realized. In the future, this will result in new important information concerning diabetes.  相似文献   
9.
Maidebura  Y. E.  Malin  T. V.  Zhuravlev  K. S. 《Semiconductors》2022,56(6):340-345
Semiconductors - The transformation of a two-dimensional GaN layer into three-dimensional islands (2D–3D transition) under increasing temperature in a flow of ammonia is investigated...  相似文献   
10.
Dense sintering of SiC nanopowder under low temperature and pressure remains a big challenge, because of the great resistance caused by the severe agglomeration of nanopowder. A novel sintering strategy is proposed to prepare SiC composite ceramics by sintering the mixture of SiC nanopowder and SiC micron powder at low temperature and pressure. The SiC micron powder was in the size of 100 µm with little sintering activity, which was designed as a pressure conductor to promote the densification of SiC nanopowder. Experimental results showed that the SiC micron powder had a significant effect on increasing of the sintering density of nanopowder and improving the mechanical properties of SiC ceramics. An SiC composite ceramic with a relative density of 98%, a Vickers hardness of 22.6 GPa, and a fracture toughness of 5.43 MPa m1/2 could be sintered by spark plasma sintering under 1700°C and 30 MPa by adding 30 wt.% 100 µm SiC micron powder as reinforcements.  相似文献   
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