Polarization control of isolated high-harmonic pulses

High-harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, thus far, the shortest isolated attosecond pulses have only been produced with linear polarization, which limits the range of physics that can be explored. Here, we demonstrate robust polarization control of isolated extreme-ultraviolet pulses by exploiting non-collinear high-harmonic generation driven by two counter-rotating few-cycle laser beams. The circularly polarized supercontinuum is produced at a central photon energy of 33 eV with a transform limit of 190 as and a predicted linear chirp of 330 as. By adjusting the ellipticity of the two counter-rotating driving pulses simultaneously, we control the polarization state of isolated extreme-ultraviolet pulses—from circular through elliptical to linear polarization—without sacrificing conversion efficiency. Access to the purely circularly polarized supercontinuum, combined with full helicity and ellipticity control, paves the way towards attosecond metrology of circular dichroism.The experimental work was carried out at National Tsing Hua University, Institute of Photonics Technologies, supported by the Ministry of Science and Technology, Taiwan (grants 105-2112-M-007-030-MY3, 105-2112-M-001-030 and 104-2112-M-007-012-MY3). The concept of isolated circularly polarized attosecond pulses was developed by C.H.-G., D.D.H., M.M.M., C.G.D., H.C.K., A.B. and A.J.-B.. C.H.-G. acknowledges support from the Marie Curie International Outgoing Fellowship within the EU Seventh Framework Programme for Research and Technological Development (2007–2013), under Research Executive Agency grant agreement no. 328334. C.H.-G. and L.P. acknowledge support from Junta de Castilla y León (SA046U16) and the Ministerio de Economía y Competitividad (FIS2013-44174-P, FIS2016-75652-P). C.H.-G. acknowledges support from a 2017 Leonardo Grant for Researchers and Cultural Creators (BBVA Foundation). M.M.M. and H.C.K. acknowledge support from the Department of Energy Basic Energy Sciences (award no. DE-FG02-99ER14982) for the concepts and experimental set-up. For part of the theory, A.B., A.J.-B., C.G.D., M.M.M. and H.C.K. acknowledge support from a Multidisciplinary University Research Initiatives grant from the Air Force Office of Scientific Research (award no. FA9550-16-1-0121). A.J.-B. also acknowledges support from the US National Science Foundation (grant no. PHY-1734006). This work utilized the Janus supercomputer, which is supported by the US National Science Foundation (grant no. CNS-0821794) and the University of Colorado, Boulder. This research made use of the high-performance computing resources of the Castilla y León Supercomputing Center (SCAYLE, www.scayle.es), financed by the European Regional Development Fund (ERDF). J.L.E. acknowledges support from the National Science Foundation Graduate Research Fellowship (DGE-1144083). L.R. acknowledges support from the Ministerio de Educación, Cultura y Deporte (FPU16/02591)

Transcriptional Regulation by CHIP/LDB Complexes

It is increasingly clear that transcription factors play versatile roles in turning genes “on” or “off” depending on cellular context via the various transcription complexes they form. This poses a major challenge in unraveling combinatorial transcription complex codes. Here we use the powerful genetics of Drosophila combined with microarray and bioinformatics analyses to tackle this challenge. The nuclear adaptor CHIP/LDB is a major developmental regulator capable of forming tissue-specific transcription complexes with various types of transcription factors and cofactors, making it a valuable model to study the intricacies of gene regulation. To date only few CHIP/LDB complexes target genes have been identified, and possible tissue-dependent crosstalk between these complexes has not been rigorously explored. SSDP proteins protect CHIP/LDB complexes from proteasome dependent degradation and are rate-limiting cofactors for these complexes. By using mutations in SSDP, we identified 189 down-stream targets of CHIP/LDB and show that these genes are enriched for the binding sites of APTEROUS (AP) and PANNIER (PNR), two well studied transcription factors associated with CHIP/LDB complexes. We performed extensive genetic screens and identified target genes that genetically interact with components of CHIP/LDB complexes in directing the development of the wings (28 genes) and thoracic bristles (23 genes). Moreover, by in vivo RNAi silencing we uncovered novel roles for two of the target genes, xbp1 and Gs-alpha, in early development of these structures. Taken together, our results suggest that loss of SSDP disrupts the normal balance between the CHIP-AP and the CHIP-PNR transcription complexes, resulting in down-regulation of CHIP-AP target genes and the concomitant up-regulation of CHIP-PNR target genes. Understanding the combinatorial nature of transcription complexes as presented here is crucial to the study of transcription regulation of gene batteries required for development

A Glial Variant of the Vesicular Monoamine Transporter Is Required To Store Histamine in the Drosophila Visual System

Unlike other monoamine neurotransmitters, the mechanism by which the brain's histamine content is regulated remains unclear. In mammals, vesicular monoamine transporters (VMATs) are expressed exclusively in neurons and mediate the storage of histamine and other monoamines. We have studied the visual system of Drosophila melanogaster in which histamine is the primary neurotransmitter released from photoreceptor cells. We report here that a novel mRNA splice variant of Drosophila VMAT (DVMAT-B) is expressed not in neurons but rather in a small subset of glia in the lamina of the fly's optic lobe. Histamine contents are reduced by mutation of dVMAT, but can be partially restored by specifically expressing DVMAT-B in glia. Our results suggest a novel role for a monoamine transporter in glia that may be relevant to histamine homeostasis in other systems

Essential Medicines at the National Level : The Global Asthma Network's Essential Asthma Medicines Survey 2014

Patients with asthma need uninterrupted supplies of affordable, quality-assured essential medicines. However, access in many low- and middle-income countries (LMICs) is limited. The World Health Organization (WHO) Non-Communicable Disease (NCD) Global Action Plan 2013-2020 sets an 80% target for essential NCD medicines' availability. Poor access is partly due to medicines not being included on the national Essential Medicines Lists (EML) and/or National Reimbursement Lists (NRL) which guide the provision of free/subsidised medicines. We aimed to determine how many countries have essential asthma medicines on their EML and NRL, which essential asthma medicines, and whether surveys might monitor progress. A cross-sectional survey in 2013-2015 of Global Asthma Network principal investigators generated 111/120 (93%) responses41 high-income countries and territories (HICs); 70 LMICs. Patients in HICs with NRL are best served (91% HICs included ICS (inhaled corticosteroids) and salbutamol). Patients in the 24 (34%) LMICs with no NRL and the 14 (30%) LMICs with an NRL, however no ICS are likely to have very poor access to affordable, quality-assured ICS. Many LMICs do not have essential asthma medicines on their EML or NRL. Technical guidance and advocacy for policy change is required. Improving access to these medicines will improve the health system's capacity to address NCDs.Peer reviewe

China's CO2 pipeline development strategy under carbon neutrality

Under China's goal of carbon neutrality, there is a huge demand for carbon dioxide (CO2) capture, utilization, and storage technology (CCUS). CO2 transport, as a crucial link in the CCUS industrial chain, will inevitably rely on the construction of long-distance CO2 pipelines and infrastructure. Due to the late start and small scale of China's CO2 pipeline construction, and the relative lag in related technologies and policies, it is urgent to make systematical planning and achieve relevant technological breakthroughs for the future construction of CO2 pipeline network as a public infrastructure. Therefore, a three-stage pipeline development path is proposed based on the analysis of the spatial distribution characteristics and the temporal pattern of large-scale commercial development of CO2 carbon sources and storage in China. Moreover, solutions and suggestions are proposed upon the developments analysis in China from the perspectives of pipeline transportation technology, safety evaluation, materials and equipment, and integrity. The results show that the construction of CO2 pipeline network as an important CCUS infrastructure will accelerate with the development of the global CCUS industry; the spatial distribution of CO2 emission sources and storage is unbalanced in China, with 65.8% from the eastern and central China, and CO2 flooding and geological storage contributing to most of large-scale CO2 pipeline transportation. The conclusions are as follows. First, the three-stage development path is a million-ton demonstration project of supercritical CO2 transmission pipeline before China peaks carbon emissions. After the achievement of carbon peak, a 10 million-ton regional network architecture of CO2 pipeline network centered on basins will be built, and trunk pipelines between regions will be formed before achieving carbon neutrality, establishing the national carbon transmission network with a transportation capacity of 10 × 108 ton, and a total mileage of approximately 6 × 104 km. Second, we should carry out research on the technology and equipment for the full phase CO2 pipeline transportation onshore and offshore, improve the domestic pipeline transportation technology, and promote the continuous improvement of the regulatory system in the pipeline transportation industry, so as to facilitate the implementation of demonstration projects

Strategies and Countermeasures for Ensuring Energy Security in China

Energy security is important for the security system of a country. Affected by global geopolitics and the COVID-19 pandemic, China’s energy security is currently facing severe challenges. Reducing the import scale of oil and gas based on the comprehensive and efficient utilization of domestic energy to ensure energy security remains a topic that requires research for promoting China’s high-quality and sustainable development. This study first reviews the evolution of the energy security concept and summarizes the energy security strategies of typical countries. Then the energy security in China is defined from five dimensions: sustainable development, guaranteed supply, scientific support, economic affordability, and guaranteed system. Moreover, the situation faced by China’s energy security is studied and corresponding strategies are proposed. We propose that China should make efforts to stabilize the production of traditional energies, ensure the supply of imported oil and gas, promote renewable energy consumption to complement the current energy mix, encourage cooperative innovation of energy science and technology, and improve the energy development mechanism. Furthermore, we propose several policy suggestions to ensure China’s energy security from the aspects of top-level plan, integrated development of gas and renewable energies, scientific innovation of renewable energies, and international cooperation

Energy Revolution and Security Guarantee of China’s Energy Economy

Energy is the blood for economic operation. Energy structure adjustment may significantly impact the macroeconomic operation of a country. This study quantitatively estimates the effect of energy structure adjustment on energy prices and further evaluates the impact of the resulted price changes on macroeconomic operations using an econometric model and statistical methods. The results indicate that 1% increase of the proportion of natural gas consumption in the total energy consumption raises energy prices by 0.8% while 1% increase of the coal consumption ratio lowers energy prices by 0.2%. Moreover, technological progress, energy investment growth, increased marketization, and energy efficiency improvement are conducive to reducing energy prices. We conclude that China’s energy revolution is less likely to affect the security of the energy economy and the energy price rise remains within the acceptable range of national economy and energy consumption. To better ensure the security of energy economy in the process of China’s energy revolution, we propose that China should focus on technology innovation and deepen the reforms in the energy market to improve the competitiveness of the energy market. These measures are beneficial for mitigating the energy price increase pressure from energy revolution