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| 2. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
- Feitosa, Mary F., et al.
(författare)
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Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries
- 2018
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Ingår i: PLOS ONE. - : Public library science. - 1932-6203. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in approximate to 131 K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P <1.0 x 10(-5)). In Stage 2, these SNVs were tested for independent external replication in individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10(-8)). For African ancestry samples, we detected 18 potentially novel BP loci (P< 5.0 x 10(-8)) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2 have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension.
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| 5. |
- Gao, Haichang, et al.
(författare)
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Extended Security Analysis of Hollow Captchas
- 2018
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Ingår i: Journal of Internet Technology. - Taiwan, Republic of China : National Dong Hwa University * Computer Center. - 1607-9264 .- 2079-4029. ; 19:4, s. 1075-1088
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Tidskriftsartikel (refereegranskat)abstract
- Text-based Captchas are now most widely used security technology for differentiating between computers and humans. Hollow Captchas have emerged as one of the latest designs, and they have been deployed by more and more major companies. Besides Yahoo!, Tencent, Sina, China Mobile and Baidu, some other websites, especially for higher security requirement shopping websites are also using this scheme. A main feature of such schemes is to use contour lines to form connected hollow characters with the aim of improving security and usability simultaneously. It is hard for standard techniques to segment and recognize such connected characters, which are however easy for human eyes. In this paper, we provide a systematic security analysis of hollow Captchas. We show that with a simple but novel attack, we can break most hollow Captchas with a relatively high success rate, including those deployed by the major companies. Our attack for the first time combines segmentation and recognition in a single step. We also discuss lessons and guidelines for designing better Captchas.
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| 6. |
- Higgins, Charlotte, et al.
(författare)
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Planning tools and methods for systems facing high levels of distributed energy resources
- 2023
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Konferensbidrag (refereegranskat)abstract
- It is important for utilities to plan for Distributed Energy Resources (DER) uptake by representing and modelling their characteristics using appropriate assumptions, methods and tools. Large-scale DER deployment impacts power flows and power system performance in various complex ways as well as potentially contributing to ancillary services. In this paper, we explore state of the art planning methods and tools being developed and deployed by utilities internationally, for systems facing high levels of distributed energy resources. This is part of technical working group C1 6.42 and our findings will be further expanded in the full technical brochure to be published in 2023. A survey of 17 international utilities was carried out to inform our study. In network planning, DER can broadly be treated similar to any other energy source. However, complexity arises particularly from several aspects: 1) how to model the impact of diverse, distributed DER at transmission and distribution network level and 2) how to model and characterise the impact of higher uncertainty from DER. This has led to a wider range of study conditions being considered using clustered time series and probabilistic methods to efficiently capture varying geospatial generation and demand during different times and seasons.Novel modelling approaches to representing DER in steady state and dynamic/transient studies have also been developed. These can have strengths and weaknesses and simulations of severe grid disturbances often fail to reproduce the widespread tripping of DER that can occur in reality, for example. Plant specific tuning for DER models and EMT modelling of high penetration networks are under development to better model behaviour under transient conditions. In order to provide greater whole-system representation, EMTP type numerical tools have been used to solve load flow problems with both transmission systems and distribution systems integrated into one network model. Hybrid/co-simulation approaches and dynamic phasor techniques are also being explored. More sophisticated and innovative statistical methods are also being applied to understand the impacts of DER and other uncertainty. Development of resilience standards and a more standardised approach to resilience modelling will support the improved consideration and contribution of DER in a resilient, decarbonised grid.
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| 7. |
- Li, Zhen, et al.
(författare)
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Soil incubation methods lead to large differences in inferred methane production temperature sensitivity
- 2024
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Ingår i: Environmental Research Letters. - 1748-9326. ; 19:4
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Tidskriftsartikel (refereegranskat)abstract
- Quantifying the temperature sensitivity of methane (CH4) production is crucial for predicting how wetland ecosystems will respond to climate warming. Typically, the temperature sensitivity (often quantified as a Q10 value) is derived from laboratory incubation studies and then used in biogeochemical models. However, studies report wide variation in incubation-inferred Q10 values, with a large portion of this variation remaining unexplained. Here we applied observations in a thawing permafrost peatland (Stordalen Mire) and a well-tested process-rich model (ecosys) to interpret incubation observations and investigate controls on inferred CH4 production temperature sensitivity. We developed a field-storage-incubation modeling approach to mimic the full incubation sequence, including field sampling at a particular time in the growing season, refrigerated storage, and laboratory incubation, followed by model evaluation. We found that CH4 production rates during incubation are regulated by substrate availability and active microbial biomass of key microbial functional groups, which are affected by soil storage duration and temperature. Seasonal variation in substrate availability and active microbial biomass of key microbial functional groups led to strong time-of-sampling impacts on CH4 production. CH4 production is higher with less perturbation post-sampling, i.e. shorter storage duration and lower storage temperature. We found a wide range of inferred Q10 values (1.2–3.5), which we attribute to incubation temperatures, incubation duration, storage duration, and sampling time. We also show that Q10 values of CH4 production are controlled by interacting biological, biochemical, and physical processes, which cause the inferred Q10 values to differ substantially from those of the component processes. Terrestrial ecosystem models that use a constant Q10 value to represent temperature responses may therefore predict biased soil carbon cycling under future climate scenarios.
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| 8. |
- Roberts, Jason D., et al.
(författare)
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Ankyrin-B dysfunction predisposes to arrhythmogenic cardiomyopathy and is amenable to therapy
- 2019
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Ingår i: Journal of Clinical Investigation. - : AMER SOC CLINICAL INVESTIGATION INC. - 0021-9738 .- 1558-8238. ; 129:8, s. 3171-3184
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Tidskriftsartikel (refereegranskat)abstract
- Arrhythmogenic cardiomyopathy (ACM) is an inherited arrhythmia syndrome characterized by severe structural and electrical cardiac phenotypes, including myocardial fibrofatty replacement and sudden cardiac death. Clinical management of ACM is largely palliative, owing to an absence of therapies that target its underlying pathophysiology, which stems partially from our limited insight into the condition. Following identification of deceased ACM probands possessing ANK2 rare variants and evidence of ankyrin-B loss of function on cardiac tissue analysis, an ANK2 mouse model was found to develop dramatic structural abnormalities reflective of human ACM, including biventricular dilation, reduced ejection fraction, cardiac fibrosis, and premature death. Desmosomal structure and function appeared preserved in diseased human and murine specimens in the presence of markedly abnormal beta-catenin expression and patterning, leading to identification of a previously unknown interaction between ankyrin-B and beta-catenin. A pharmacological activator of the WNT/beta-catenin pathway, SB-216763, successfully prevented and partially reversed the murine ACM phenotypes. Our findings introduce what we believe to be a new pathway for ACM, a role of ankyrin-B in cardiac structure and signaling, a molecular link between ankyrin-B and beta-catenin, and evidence for targeted activation of the WNT/beta-catenin pathway as a potential treatment for this disease.
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| 9. |
- Setlur, Sunita R., et al.
(författare)
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Estrogen-dependent signaling in a molecularly distinct subclass of aggressive prostate cancer
- 2008
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Ingår i: Journal of the National Cancer Institute. - Oxford : Oxford University Press. - 0027-8874 .- 1460-2105. ; 100:11, s. 815-825
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The majority of prostate cancers harbor gene fusions of the 5'-untranslated region of the androgen-regulated transmembrane protease serine 2 (TMPRSS2) promoter with erythroblast transformation-specific transcription factor family members. The common fusion between TMPRESS2 and v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG) is associated with a more aggressive clinical phenotype, implying the existence of a distinct subclass of prostate cancer defined by this fusion. METHODS: We used complementary DNA-mediated annealing, selection, ligation, and extension to determine the expression profiles of 6144 transcriptionally informative genes in archived biopsy samples from 455 prostate cancer patients in the Swedish Watchful Waiting cohort (1987-1999) and the United States-based Physicians(') Health Study cohort (1983-2003). A gene expression signature for prostate cancers with the TMPRSS2-ERG fusion was determined using partitioning and classification models and used in computational functional analysis. Cell proliferation and TMPRSS2-ERG expression in androgen receptor-negative (NCI-H660) prostate cancer cells after treatment with vehicle or estrogenic compounds were assessed by viability assays and quantitative polymerase chain reaction, respectively. All statistical tests were two-sided. RESULTS: We identified an 87-gene expression signature that distinguishes TMPRSS2-ERG fusion prostate cancer as a discrete molecular entity (area under the curve = 0.80, 95% confidence interval [CI] = 0.792 to 0.81; P < .001). Computational analysis suggested that this fusion signature was associated with estrogen receptor (ER) signaling. Viability of NCI-H660 cells decreased after treatment with estrogen (viability normalized to day 0, estrogen vs vehicle at day 8, mean = 2.04 vs 3.40, difference = 1.36, 95% CI = 1.12 to 1.62) or ERbeta agonist (ERbeta agonist vs vehicle at day 8, mean = 1.86 vs 3.40, difference = 1.54, 95% CI = 1.39 to 1.69) but increased after ERalpha agonist treatment (ERalpha agonist vs vehicle at day 8, mean = 4.36 vs 3.40, difference = 0.96, 95% CI = 0.68 to 1.23). Similarly, expression of TMPRSS2-ERG decreased after ERbeta agonist treatment (fold change over internal control, ERbeta agonist vs vehicle at 24 hours, NCI-H660, mean = 0.57- vs 1.0-fold, difference = 0.43-fold, 95% CI = 0.29- to 0.57-fold) and increased after ERalpha agonist treatment (ERalpha agonist vs vehicle at 24 hours, mean = 5.63- vs 1.0-fold, difference = 4.63-fold, 95% CI = 4.34- to 4.92-fold). CONCLUSIONS: TMPRSS2-ERG fusion prostate cancer is a distinct molecular subclass. TMPRSS2-ERG expression is regulated by a novel ER-dependent mechanism.
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| 10. |
- Shaw, Jeff, et al.
(författare)
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Inflammatory processes are specifically enhanced in endothelial cells by placental-derived TNF-α : Implications in preeclampsia (PE)
- 2016
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Ingår i: Placenta. - : Elsevier BV. - 0143-4004. ; 43, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Introduction There is a consensus that factors released by the placenta to maternal circulation, including TNF-α, play a key role in activating the maternal endothelium in pregnancies with preeclampsia (PE). Dual perfusion preserves the structural organization of the placenta to a greater degree than other in vitro systems and has been used by our group and others to examine placental pathophysiology associated with PE. The objective of this study was to use the dual perfusion model to test whether TNF-α released by the placenta to maternal perfusate affects pro-inflammatory cytokine secretion by, and activation of, endothelial cells, thereby furthering our understanding of placental and endothelial dysfunction in PE. Method We used maternal perfusate, two endothelial cell lines (HUVECs and HEECs), and a TNF-α blocking antibody to test whether placental-derived TNF-α plays a significant role in altering the expression and secretion of pro-inflammatory cytokines in endothelial cells as well as the expression of activation markers in this cell type. Results The presence of maternal perfusate significantly enhanced IL-6, IL-8, and MCP-1 secretion, levels of their mRNA, as well as mRNA levels of markers of endothelial activation (E-selectin, ICAM-1, and VCAM-1). The addition of a TNF-α blocking antibody significantly inhibited the maternal perfusate-mediated enhancement of cytokine secretion by, and expression of activation markers, in both HUVECs and HEECs. Discussion These results demonstrate that TNF-α significantly contributed to endothelial cell pro-inflammatory cytokine secretion and activation suggesting that blocking TNF-α action may mitigate the effects of maternal endothelial dysfunction in PE.
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