1,308 research outputs found

    Farming the planet with better nitrogen use

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    Feeding an increasingly affluent population is a huge challenge facing global agriculture. In contrast to “large-scale farming” in developed economies (e.g. Europe and the United States), developing countries are dominated by “smallholder farms” relying on traditional farming practices but increasingly with substantial nitrogen overuse leading to severe environmental degradation and adverse human health. Here, we explore the potential for better nitrogen use by synthesizing the global relationship between farm size and nitrogen use for 16 major crops, assess the impact of farm size on nitrogen flows, and link these with air quality modelling to produce an integrated assessment of nitrogen-related environmental and health outcomes related to farm size. We find that increasing farm size in developing countries can contribute to more efficient and sustainable farming practices, which could decrease nitrogen overuse, ammonia emissions and nitrogen deposition by 20-25%, increase nitrogen use efficiency by 2-8%, and save over 142,000 premature deaths per year related to PM2.5 air pollution. Although a large one-time investment is required for increasing farm size, there would be substantial progress towards achieving Sustainable Development Goals, associated with food security, a clean environment and improved human health

    A FN-MdV pathway and its role in cerebellar multimodular control of sensorimotor behavior

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    The cerebellum is crucial for various associative sensorimotor behaviors. Delay eyeblink conditioning (DEC) depends on the simplex lobule-interposed nucleus (IN) pathway, yet it is unclear how other cerebellar modules cooperate during this task. Here, we demonstrate the contribution of the vermis-fastigial nucleus (FN) pathway in controlling DEC. We found that task-related modulations in vermal Purkinje cells and FN neurons predict conditioned responses (CRs). Coactivation of the FN and the IN allows for the generation of proper motor commands for CRs, but only FN output fine-tunes unconditione

    Computational neuroscience: a frontier of the 21st century

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    The human brain is a biological organ, weighing about three pounds or 1.4 kg, that determines our behaviors, thoughts, emotions and consciousness. Although comprising only 2% of the total body weight, the brain consumes about 20% of the oxygen entering the body. With the expensive energy demand, the brain enables us to perceive and act upon the external world, as well as reflect on our internal thoughts and feelings. The brain is actually never at ‘rest’. Brain activities continue around the clock, ranging from functions enabling human–environment interactions to housekeeping during sleep, including processes such as synaptic homeostasis and memory formation. Whereas one could argue that sciences in the last century were dominated by physics and molecular biology, in the current century one of our major challenges is to elucidate how the brain works. A full understanding of brain functions and malfunctions is likely the most demanding task we will ever have

    Unparticle Effects on Top Quark Pair Production at Photon Collider

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    The unparticle effects on ttˉt\bar t production at the future photon collider are investigated. Distributions of ttˉt\bar t invariant mass and that for transverse momentum of top quark with respect to Standard Model and unparticle production are predicted. An odd valley with scalar unparticle contribution appears for some values of d_{\U}, which is due to the big cancellation between the contribution from SM and that from unparticle. This character may be used to study the properties of scalar unparticle. Our investigations also show that scalar unparticle may play a significant role in ttˉt \bar t production at photon collider if it exists.Comment: 13 pages, 5figure

    Gene expression in lungs of mice lacking the 5-hydroxytryptamine transporter gene

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    <p>Abstract</p> <p>Background</p> <p>While modulation of the serotonin transporter (5HTT) has shown to be a risk factor for pulmonary arterial hypertension for almost 40 years, there is a lack of in vivo data about the broad molecular effects of pulmonary inhibition of 5HTT. Previous studies have suggested effects on inflammation, proliferation, and vasoconstriction. The goal of this study was to determine which of these were supported by alterations in gene expression in serotonin transporter knockout mice.</p> <p>Methods</p> <p>Eight week old normoxic mice with a 5-HTT knock-out (5HTT-/-) and their heterozygote(5HTT+/-) or wild-type(5HTT+/+) littermates had right ventricular systolic pressure(RVSP) assessed, lungs collected for RNA, pooled, and used in duplicate in Affymetrix array analysis. Representative genes were confirmed by quantitative RT-PCR and western blot.</p> <p>Results</p> <p>RVSP was normal in all groups. Only 124 genes were reliably changed between 5HTT-/- and 5HTT+/+ mice. More than half of these were either involved in inflammatory response or muscle function and organization; in addition, some matrix, heme oxygenase, developmental, and energy metabolism genes showed altered expression. Quantitative RT-PCR for examples from each major group confirmed changes seen by array, with an intermediate level in 5HTT +/- mice.</p> <p>Conclusion</p> <p>These results for the first time show the in vivo effects of 5HTT knockout in lungs, and show that many of the downstream mechanisms suggested by cell culture and ex vivo experiments are also operational in vivo. This suggests that the effect of 5HTT on pulmonary vascular function arises from its impact on several systems, including vasoreactivity, proliferation, and immune function.</p

    Antitumor activity and mechanisms of action of total glycosides from aerial part of Cimicifuga dahurica targeted against hepatoma

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    <p>Abstract</p> <p>Background</p> <p>Medicinal plant is a main source of cancer drug development. Some of the cycloartane triterpenoids isolated from the aerial part of <it>Cimicifuga dahurica </it>showed cytotoxicity in several cancer cell lines. It is of great interest to examine the antiproliferative activity and mechanisms of total triterpenoid glycosides of <it>C. dahurica </it>and therefore might eventually be useful in the prevention or treatment of Hepatoma.</p> <p>Methods</p> <p>The total glycosides from the aerial part (TGA) was extracted and its cytotoxicity was evaluated in HepG2 cells and primary cultured normal mouse hepatocytes by an MTT assay. Morphology observation, Annexin V-FITC/PI staining, cell cycle analysis and western blot were used to further elucidate the cytotoxic mechanism of TGA. Implanted mouse H<sub>22 </sub>hepatoma model was used to demonstrate the tumor growth inhibitory activity of TGA <it>in vivo</it>.</p> <p>Results</p> <p>The IC<sub>50 </sub>values of TGA in HepG2 and primary cultured normal mouse hepatocytes were 21 and 105 μg/ml, respectively. TGA induced G<sub>0</sub>/G<sub>1 </sub>cell cycle arrest at lower concentration (25 μg/ml), and triggered G<sub>2</sub>/M arrest and apoptosis at higher concentrations (50 and 100 μg/ml respectively). An increase in the ratio of Bax/Bcl-2 was implicated in TGA-induced apoptosis. In addition, TGA inhibited the growth of the implanted mouse H<sub>22 </sub>tumor in a dose-dependent manner.</p> <p>Conclusion</p> <p>TGA may potentially find use as a new therapy for the treatment of hepatoma.</p

    Smoking and COX-2 Functional Polymorphisms Interact to Increase the Risk of Gastric Cardia Adenocarcinoma in Chinese Population

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    BACKGROUND: Over-expression and increased activity of cyclooxygenase (COX)-2 induced by smoking has been implicated in the development of cancer. This study aimed to explore the interaction between smoking and functional polymorphisms of COX-2 in modulation of gastric cardia adenocarcinoma (GCA) risk. METHODS AND FINDINGS: Three COX-2 polymorphisms, including -1195G>A (rs689466), -765G>C (rs20417), and 587Gly>Arg (rs3218625), were genotyped in 357 GCA patients and 985 controls. In the multivariate logistic regression analysis, we found that the -1195AA, -765GC, and 587Arg/Arg genotypes were associated with increased risk of GCA (OR = 1.50, 95% CI = 1.05-2.13; OR = 2.06, 95% CI = 1.29-3.29 and OR = 1.67, 95% CI = 1.04-2.66, respectively). Haplotype association analysis showed that compared with G(-1195)-G(-765)- G(Gly587Arg), the A(-1195)-C(-765)-A(Gly587Arg) conferred an increased risk of GCA (OR = 2.49, 95% CI = 1.54-4.01). Moreover, significant multiplicative interactions were observed between smoking and these three polymorphisms of -1195G>A, -765G>C, and 587Gly>Arg, even after correction by false discovery rate (FDR) method for multiple comparisons (FDR-P(interaction) = 0.006, 5.239×10(-4) and 0.017, respectively). Similarly, haplotypes incorporating these three polymorphisms also showed significant interaction with smoking in the development of GCA (P for multiplicative interaction = 2.65×10(-6)). CONCLUSION: These findings indicated that the functional polymorphisms of COX-2, in interaction with smoking, may play a substantial role in the development of GCA
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