80 research outputs found
Fractional strong matching preclusion for two variants of hypercubes
Let F be a subset of edges and vertices of a graph G. If G-F has no fractional perfect matching, then F is a fractional strong matching preclusion set of G. The fractional strong matching preclusion number is the cardinality of a minimum fractional strong matching preclusion set. In this paper, we mainly study the fractional strong matching preclusion problem for two variants of hypercubes, the multiply twisted cube and the locally twisted cube, which are two of the most popular interconnection networks. In addition, we classify all the optimal fractional strong matching preclusion set of each
3D Spheroids of Human Primary Urine-Derived Stem Cells in the Assessment of Drug-Induced Mitochondrial Toxicity
Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes of drugs, particularly some life-long antiretroviral drugs for HIV+ individuals. However, no suitable in vitro assays are available to test long-term Mito-Tox (≥4 weeks). The goal of this study is to develop a 3D spheroid system of human primary urine-derived stem cells (USC) for the prediction of drug-induced delayed Mito-Tox. The cytotoxicity and Mito-Tox were assessed in 3D USC spheroids 4 weeks after treatment with antiretroviral drugs: zalcitabine (ddC; 0.1, 1 and 10 µM), tenofovir (TFV; 3, 30 and 300 µM) or Raltegravir (RAL; 2, 20 and 200 µM). Rotenone (RTNN, 10 µM) and 0.1% DMSO served as positive and negative controls. Despite only mild cytotoxicity, ddC significantly inhibited the expression of oxidative phosphorylation enzyme Complexes I, III, and IV; and RAL transiently reduced the level of Complex IV. A significant increase in caspase 3 and ROS/RNS level but a decrease in total ATP were observed in USC treated with ddC, TFV, RAL, and RTNN. Levels of mtDNA content and mitochondrial mass were decreased in ddC but minimally or not in TFV- and RAL-treated spheroids. Thus, 3D USC spheroid using antiretroviral drugs as a model offers an alternative platform to assess drug-induced late Mito-Tox
Divergent nitrogen and phosphorus allocation strategies in terrestrial plant leaves and fine roots: a global meta-analysis
1. The quantification of the allocation of nitrogen (N) and phosphorus (P) among plant organs is essential to improve our understanding of plant growth, life-history strategies, and ecosystem nutrient and energy cycles. However, allocation strategies of N and P between terrestrial plant leaves and fine roots are unclear.
2. Here, we compiled a global dataset comprising 807 terrestrial plant species to analyze the stoichiometric scaling of N and P between leaves and fine roots across species, families, plant groups, biomes, and locations.
3. We found that N and P, and N:P ratios manifest different scaling exponents (α-values) between leaves and fine roots. Specifically, overall αN and αP were >1 and <1, respectively, and αN:P = 1, indicating a higher proportional increase of N to fine roots and P to leaves. However, there were differences in αN, αP, and αN:P among major species, families, plant groups, biomes, and locations. In addition, αN and αN:P increased with latitude; there was no clear trend for αP. Mean annual temperature accounted for the greatest proportion of variation in αN, whereas soil total P accounted for the greatest proportion of variation in αP and αN:P.
4. Synthesis. Our results demonstrate a divergent N and P allocation strategy between leaves and fine roots in terrestrial plants. This study improves our understanding of the effects of the environment (including changes in global climate, and life history strategies) on nutrient allocation patterns between these two important plant organs.This work was funded by the European Research Council Synergy project SyG-2013-610028 IMBALANCE-P, the Catalan Government grants AGAUR-2020PANDE00117 and SGR 2017-1005, the Spanish Government grant PID2019-110521GB-I00, the Fundac ió n Ra mó n A reces gr a nt ELEMEN TA L-CLIM ATE, t he N at io na l Sc ie nc e Fund for Excellent Young Scholars (31822010), the B iod iver s it y Sur ve y a nd A ssess me nt Pro ject o f t he M inis tr y o f Ecology and Environment, C hina (2019HJ2096001006), National Scientific and Technological Program on Basic Resources Investigation (2019FY102002) and the Innovation Base Project of Gansu Province (20190323).Peer reviewe
Foreign patents surge and technology spillovers in China (1985-2009): evidence from the patent and trade markets
The paper investigates the determinants of foreign patent surge and the effects of technology spillovers in China based on an industry-level sample of 19 countries and regions from 1985 to 2009. We explore two hypotheses to explain the increasing foreign propensity to patent and the effects of technology spillovers in China, the market covering hypotheses and competitive threat hypotheses. The results show strong support for the competitive threat hypothesis. However, the foreign patenting surge in China does not mean China has more access to outsource advanced technology; on the contrary the technology spillover from foreign countries in China is limited.
The paper investigates the determinants of foreign patent surge and the effects of technology spillovers in China based on an industry-level sample of 19 countries and regions from 1985 to 2009. We explore two hypotheses to explain the increasing foreign propensity to patent and the effects of technology spillovers in China, the market covering hypotheses and competitive threat hypotheses. The results show strong support for the competitive threat hypothesis. However, the foreign patenting surge in China does not mean China has more access to outsource advanced technology; on the contrary the technology spillover from foreign countries in China is limited
Single nucleus genome sequencing reveals high similarity among nuclei of an endomycorrhizal fungus
Nuclei of arbuscular endomycorrhizal fungi have been described as highly diverse due to their asexual nature and absence of a single cell stage with only one nucleus. This has raised fundamental questions concerning speciation, selection and transmission of the genetic make-up to next generations. Although this concept has become textbook knowledge, it is only based on studying a few loci, including 45S rDNA. To provide a more comprehensive insight into the genetic makeup of arbuscular endomycorrhizal fungi, we applied de novo genome sequencing of individual nuclei of Rhizophagus irregularis. This revealed a surprisingly low level of polymorphism between nuclei. In contrast, within a nucleus, the 45S rDNA repeat unit turned out to be highly diverged. This finding demystifies a long-lasting hypothesis on the complex genetic makeup of arbuscular endomycorrhizal fungi. Subsequent genome assembly resulted in the first draft reference genome sequence of an arbuscular endomycorrhizal fungus. Its length is 141 Mbps, representing over 27,000 protein-coding gene models. We used the genomic sequence to reinvestigate the phylogenetic relationships of Rhizophagus irregularis with other fungal phyla. This unambiguously demonstrated that Glomeromycota are more closely related to Mucoromycotina than to its postulated sister Dikarya
Coordination of care in the Chinese health care systems: a gap analysis of service delivery from a provider perspective
The Structure and Effectiveness of Health Systems: Exploring the Impact of System Integration in Rural China
Facing the challenges of aging populations, increasing chronic diseases prevalence and health system fragmentation, there have been several pilots of integrated health systems in China. But little is known about their structure, mechanism and effectiveness. The aim of this paper is to analyze health system integration and develop recommendations for achieving integration.Huangzhong and Hualong counties in Qinghai province were studied as study sites, with only Huangzhong having implemented health system integration. Questionnaires, interviews, and health insurance records were sources of data. Social network analysis was employed to analyze integration, through structure measurement and effectiveness evaluation.Health system integration in Huangzhong is higher than in Hualong, so is system effectiveness. The patient referral network in Hualong has more "leapfrog" referrals. The information sharing networks in both counties are larger than the other types of networks. The average distance in the joint training network of Huangzhong is less than in Hualong. Meanwhile, there are deficiencies common to both systems.Both county health systems have strengths and limitations regarding system integration. The use of medical consortia in Huangzhong has contributed to system effectiveness. Future research might consider alternative more context specific models of health system integration
Behavior of Selenium during Chemical-Looping Gasification of Coal Using Copper-Based Oxygen Carrier
The migration and transformation behavior of selenium during coal chemical looping gasification (CLG) under the impact of a CuO/Bentonite (Ben) oxygen carrier (OC) were studied in a batch fluidized bed reactor. In the CLG process, the total percentage of selenium released in gaseous phase was 73.06%. In the conventional gasification process, 91.71% of the total selenium was released in a gaseous state. The addition of CuO/Ben OC apparently promoted the transformation from gaseous selenium to particulate selenium. The oxygen–carbon ratio (O/C) played an important role in affecting the fraction of gaseous selenium released in the gasification process, with results showing that the amount of selenium adsorbed by CuO/Ben OC was added along with the increase in OC. By means of X-ray photoelectron spectroscopy (XPS) characterization, we found that the reduced CuO/Ben OC contained a small amount of Cu2Se due to the oxidation and adsorption of selenium onto their porous surface. The regeneration performance of the CuO/Ben OC was favorable after 10 regeneration cycles of the CLG process. The increase in the pore volumes and specific surface areas contributed to the enhanced capacity of retaining selenium for CuO/Ben OC
Individual and Combined Effects of CaCl2 and UV-C on the Biosynthesis of Resveratrols in Grape Leaves and Berry Skins
The individual and combined effects of calcium chloride (CaCl2) and ultraviolet C (UV-C) light on the synthesis of resveratrol in grape leaves and berry skins were investigated. Results showed that all treatments could increase leaf resveratrol contents at least about 5 times, but the combination treatment was the most efficient. Moreover, compared with UV-C treatment, the combination treatment delayed the decline of resveratrol contents. The expression levels of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), coumaroyl-CoA ligase (4CL), and stilbene synthase (STS) and 3-O-beta-glycosyltransferases, which are related to the synthesis of resveratrol, increased in response to these treatments, paralleling the change in resveratrol content. All treatments also induced the biosynthesis of resveratrol in berry skins at room temperature. The berries of these treatments held at room temperature for 1 day were further stored under low temperature (-1 +/- 0.5 degrees C, RH 9596) for 27 days, and the results showed that all treatments continuously increased berry skin resveratrol content, with the combination treatment being most efficient. During cold storage, resveratrol content remained at high levels and reached a maximum (about 247.7 mu g/g FIN) at 13 days, then showed a slight decline, though it remained high by the end of storage. Berry firmness and total soluble solids content showed slight changes during cold storage, but there were no differences among the treatments. Thus, the combination treatment of CaCl2 and UV-C could be an efficient method for increasing resveratrol content of table grapes during storage under low temperature. This would be potentially beneficial for producing functional fruits
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