14 research outputs found
Physiological Responses of Synechocystis sp PCC 6803 under Clinorotation
Photosystem efficiency and the characteristic on oxidative stress were examined to elucidate the metabolic responses of Synechocystis sp. PCC 6803 to short-term clinorotation. Results compiled when using clinostat to simulate microgravity for 60 h, showed that clinorotation clearly prohibited the photochemical quantum yield, but promoted the synthesis of chlorophyll and total protein. This may be a compensatory mechanism for the algal cell to maintain its normal metabolism. An increased malondialdehyde (MDA) content of algal cell upon clinorotation, together with an enhanced catalase (CAT) activity was observed during the whole period of clinorotation. One conclusion is that short-term clinorotation acts as a kind of stress, and that these physiological responses may be a special way for an algal cell to adapt itself to a different environment other than earth gravity.Photosystem efficiency and the characteristic on oxidative stress were examined to elucidate the metabolic responses of Synechocystis sp. PCC 6803 to short-term clinorotation. Results compiled when using clinostat to simulate microgravity for 60 h, showed that clinorotation clearly prohibited the photochemical quantum yield, but promoted the synthesis of chlorophyll and total protein. This may be a compensatory mechanism for the algal cell to maintain its normal metabolism. An increased malondialdehyde (MDA) content of algal cell upon clinorotation, together with an enhanced catalase (CAT) activity was observed during the whole period of clinorotation. One conclusion is that short-term clinorotation acts as a kind of stress, and that these physiological responses may be a special way for an algal cell to adapt itself to a different environment other than earth gravity
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
The role of grid-size energy storage in enabling a community-level energy hub: Case study in Zuid-Oost Amsterdam Region
To follow the rapid advance of the Energy Transition, the technology and application of the renewable energy resources and energy storage devices have been developed in an unstoppable speed. When the application of energy storage technology starts to prosper gradually over the world, there are some problems showing up while lots of advantages are being advocated. There are plenty of batteries staying unused or being wasted for over half of the lifetime of the system, especially for the behind-the-meter energy storage system. The business models are usually built just for one or two primary services for customers and grid that makes only a limited part of time occupied, leaving the essential untapped values aside. And also, it is common that the energy storage system is coupled with PV panels or wind turbines. In this case, how to increase the on-site solar energy self-consumption becomes an attractive issue considering the sizeable financial benefit it can bring. What is more, when putting the attention on the neighborhood or community level where there is more than one participator in this picture, how to create the extra value or bonus benefit using the existed system and equipment can be an interesting topic. This report will focus on the grid-size battery installed behind the meter within a commercial community. A methodology of the energy hub with two different lays providing all kinds of services will be proposed. As the result, the value of grid-size energy storage in enabling a community-level energy hub for both battery-owner and neighbors will be explored to cope with all the above problems. There will be a case study conducted in the selected Zuid-Oost Amsterdam region. In the end, how much benefit the energy hub can create for not only the battery-owner but also for the whole community and society will be discussed.Electrical Engineering | Electrical Power Engineerin
戰國末秦漢之際黃老學說之探討
[[abstract]]本文研究的目的,乃鑑於黃老學說資料闕如,大多語焉不詳,而經法等四篇佚書出土
,研究黃老的文字才漸多,且具眉目,但是猶未有全盤探討黃老源起、興盛、沒落的
專著。加以黃老學說顯示了由先秦到漢朝學術的過渡融合性質,研究本題,有助於澄
清漢朝學術的動向,所以搦筆合墨,完成此篇。
本文研究方法以考證材料及義理闡析兩者交互為用,並採用沿波上下的歷史觀點,陳
述黃老學說在戰國末秦漢之際的流衍。
第一章緒論,首先確立經法四篇佚書的性質屬黃老學派。
第二章黃老學說的源起,分析黃老學說與老子、稷下學派、申韓列名、黃帝傳說及黃
帝書的關係,考察黃老學說的來源。
第三章黃老學說的人物,著作考旨在確定研究黃老學說的可靠資料。
第四章黃老學說的思想分析,就黃老學的人物,著作考證的範圍以闡發幽旨。
第五章敘述漢初黃老學說的盛況。
第六章黃老學說的沒落及內在限制,分析黃老學說沒落的緣由。
第七章結論,探討黃老學說的影響,並比較本文與先進研究黃老學說的異同。
本文以為,黃老學說可能發揚於稷下宋鉼、尹文後學手中,而現今研究黃老的可靠資
料,僅有經法四篇佚書,呂氏春秋、淮南子、文子、鶡冠子等書暫不應列屬黃老學派
。
本文引用參考文獻,以馬王堆漢墓出土之經法四篇帛書為主,復引用先秦以來經、史
、子、集各書,及今人研究黃老之篇章,以完成探討。
Investigation of the moisture damage and the erosion depth on asphalt
Moisture erosion is one of the key factors leading to asphalt pavement damage, and the erosion depth indicates the moisture damage level but it is usually neglected. In order to study the moisture erosion and the erosion depth, this study characterized the chemical structure, rheological property and adhesion property of asphalt at different depths after immersion for different periods. To further explore the diffusion mechanism of eroded asphalt, a Log-log numerical model was established based on the Fick's second law to calculate the diffusion coefficient throughout the depth. The results indicate that it takes just four hours for water to penetrate a 25 μm asphalt film. The relation between erosion depth and immersion period presents three stages, and the process can be fitted with a polynomial model. At the macroscopic level, there is a lag between the changes in adhesion property with chemical structure and rheological property. Additionally, the periodicity of moisture erosion process was verified by the calculation of diffusion factor. In summary, the diffusion mechanism of eroded asphalt by moisture can provide a theoretical basis for the development of laboratory moisture erosion test specification, thus avoiding the waste of raw materials.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen
Investigation of the Rheological Properties and Chemical Structure of Asphalt under Multiple Aging Conditions of Heat, UV and Aqueous Solution
During the service period, asphalt materials are affected by various natural factors, including heat, ultraviolet light, oxygen and moisture, etc., resulting in the reduction of pavement performance, the increase of pavement distress and shortening of service life. This study aims to investigate the aging performance of asphalt under multiple aging conditions of heat, UV and aqueous solution. Thermal-oxygen aging, UV aging and hydrostatic erosion tests were carried out sequentially on asphalt. The rheological properties, chemical structure and element composition of asphalt were characterized before and after aging, and the effect mechanism of multiple conditions was discussed. The results show that the multiple conditions of heat and UV can increase the rutting resistance and weaken the cracking resistance of asphalt. However, the effect degree of UV decreases gradually with the deepening of aging degree. Additionally, the effect of water on the physicochemical properties is less than that of UV; however, water can increase the sensitivity of physicochemical properties to UV. In summary, this study explored the short-term cycling effect of heat, light and water on asphalt and provided an idea for simulation test of asphalt under multiple aging condition.Materials and Environmen
Intrinsic-Strain Engineering by Dislocation Imprint in Bulk Ferroelectrics
We report an intrinsic strain engineering, akin to thin filmlike approaches, via irreversible high-temperature plastic deformation of a tetragonal ferroelectric single-crystal BaTiO3. Dislocations well-aligned along the [001] axis and associated strain fields in plane defined by the [110]/[1¯10] plane are introduced into the volume, thus nucleating only in-plane domain variants. By combining direct experimental observations and theoretical analyses, we reveal that domain instability and extrinsic degradation processes can both be mitigated during the aging and fatigue processes, and demonstrate that this requires careful strain tuning of the ratio of in-plane and out-of-plane domain variants. Our findings advance the understanding of structural defects that drive domain nucleation and instabilities in ferroic materials and are essential for mitigating device degradation.RST/Storage of Electrochemical Energ
An Improved Method for Mapping Tidal Flats Based on Remote Sensing Waterlines: A Case Study in the Bohai Rim, China
Tidal flats form boundaries between marine and terrestrial environments, and reported rapid decreases in their extent require improved measures of their status. Current methods for delineating tidal flats have low accuracy because of the limited precision of available imagery, and they cannot identify zones within tidal flats. Three zones within tidal flats are ecologically distinct due to their varied inundation. These include the supratidal, intertidal, and subtidal zones. In this study, we present a more precise method for mapping tidal flats. We used Chinese HJ-1A/B satellite images with a semiautomatic extraction method to generate a sufficient number of waterline estimates taken at various tide heights to delineate the full extent of tidal flats. Then, the full set of waterline estimates is analyzed with the Digital Shoreline Analysis System (DSAS) using Jenks Natural Breaks to identify three zones within tidal flats. We demonstrated the utility of this approach by mapping tidal flats of the Bohai Rim, China. In 2014, the estimate of available tidal flats in the region was 3093 km(2), among which the area of supratidal, intertidal, and subtidal zones accounted for 5.0%, 84.3%, and 10.7%, respectively. A confusion matrix for accuracy assessment revealed a 93.8% overall accuracy for the resulting tidal flat map. Our method enables tidal flats to be mapped and monitored precisely and comprehensively, providing baseline data on the extent of this disappearing ecosystem that can be used to inform coastal planning and sustainable development
Unraveling the genome structure of cyanobacterial podovirus A-4L with long direct terminal repeats
The freshwater cyanobacterial virus (cyanophage) A-4L, a podovirus, can infect the model cyanobacterium Anabaena sp. strain PCC 7120 resulting in a high burst size and forming concentric plaques on its lawns. The complete genome sequence of A-4L was determined by the combination of high-throughput sequencing, terminal transferase-mediated polymerase chain reaction and restriction mapping. It contains 41,750 bp with 810 bp direct terminal repeats and 38 potential open reading frames. As compared with other cyanobacterial podoviruses in diverse ecosystems, the A-4L has the longest terminal repeat and shares similar genome organizations with freshwater members. Furthermore, phylogenetic analysis based on concatenated sequences of eight core proteins indicated that freshwater cyanobacterial podoviruses were clustered together and distinct from marine counterparts, suggesting a clear divergence in the cyanobacterial podovirus lineage between freshwater and marine ecosystems. Our findings uncover the unique genome structure of A-4L which contains long direct terminal repeats, and create the first model system to address knowledge gaps in understanding cyanobacterial virus-host interactions at the molecular level. (C) 2015 Elsevier B.V. All rights reserved
Morphological alterations and acetylcholinesterase and monoamine oxidase inhibition in liver of zebrafish exposed to Aphanizomenon flos-aquae DC-1 aphantoxins
Aphanizomenon flos-aquae is a cyanobacterium that produces neurotoxins or paralytic shellfish poisons (PSPs) called aphantoxins, which present threats to environmental safety and human health via eutrophication of water bodies worldwide. Although the molecular mechanisms of this neurotoxin have been studied, many questions remain unsolved, including those relating to in vivo hepatic neurotransmitter inactivation, physiological detoxification and histological and ultrastructural alterations. Aphantoxins extracted from the natural strain of A. flos-aquae DC-1 were analyzed by high-performance liquid chromatography. The main components were gonyautoxins 1 and 5 (GTX1, GTX5) and neosaxitoxin (neoSTX), which comprised 34.04%, 21.28%, and 12.77% respectively. Zebrafish (Danio rerio) were exposed intraperitoneally to 5.3 or 7.61 mu g STX equivalents (eq)/kg (low and high doses, respectively) of A. flos-aquae DC-1 aphantoxins. Morphological alterations and changes in neurotransmitter conduction functions of acetylcholinesterase (AChE) and monoamine oxidase (MAO) in zebrafish liver were detected at different time points 1-24 h post-exposure. Aphantoxin significantly enhanced hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and histological and ultrastructural damage in zebrafish liver at 3-12 h post-exposure. Toxin exposure increased the reactive oxygen species content and reduced total antioxidative capacity in zebrafish liver, suggesting oxidative stress. AChE and MAO activities were significantly inhibited, suggesting neurotransmitter inactivation/conduction function abnormalities in zebrafish liver. All alterations were dose- and time-dependent. Overall, the results indicate that aphantoxins/PSPs induce oxidative stress through inhibition of AChE and MAO activities, leading to neurotoxicity in zebrafish liver. The above parameters may be useful as bioindicators for investigating aphantoxins/PSPs and cyanobacterial blooms in nature. (C) 2014 Published by Elsevier B.V