CO_2 semiannual oscillation in the middle troposphere and at the surface

Using in situ measurements, we find a semiannual oscillation (SAO) in the midtropospheric and surface CO_2. Chemistry transport models (2-D Caltech/JPL model, 3-D GEOS-Chem, and 3-D MOZART-2) are used to investigate possible sources for the SAO signal in the midtropospheric and surface CO_2. From model sensitivity studies, it is revealed that the SAO signal in the midtropospheric CO_2 originates mainly from surface CO_2 with a small contribution from transport fields. It is also found that the source for the SAO signal in surface CO_2 is mostly related to the CO_2 exchange between the biosphere and the atmosphere. By comparing model CO_2 with in situ CO_2 measurements at the surface, we find that models are able to capture both annual and semiannual cycles well at the surface. Model simulations of the annual and semiannual cycles of CO_2 in the tropical middle troposphere agree reasonably well with aircraft measurements

Influence of El Niño on Midtropospheric CO_2 from Atmospheric Infrared Sounder and Model

The authors investigate the influence of El Niño on midtropospheric CO_2 from the Atmospheric Infrared Sounder (AIRS) and the Model for Ozone and Related Chemical Tracers, version 2 (MOZART-2). AIRS midtropospheric CO_2 data are used to study the temporal and spatial variability of CO_2 in response to El Niño. CO_2 differences between the central and western Pacific Ocean correlate well with the Southern Oscillation index. To reveal the temporal and spatial variability of the El Niño signal in the AIRS midtropospheric CO_2, a multiple regression method is applied to the CO_2 data from September 2002 to February 2011. There is more (less) midtropospheric CO_2 in the central Pacific and less (more) midtropospheric CO_2 in the western Pacific during El Niño (La Niña) events. Similar results are seen in the MOZART-2 convolved midtropospheric CO_2, although the El Niño signal in the MOZART-2 is weaker than that in the AIRS data

A novel phosphorylation site on orexin receptor 1 regulating orexinA-induced GRK2-biased signaling

Drug discovery efforts targeting G protein–coupled receptors (GPCRs) have succeeded in developing multiple medications for treating various human diseases including cancer, metabolic disorders, and inflammatory disorders. These medications are broadly classified as either agonists or antagonists that respectively promote or inhibit receptor activation by endogenous stimuli. However, there has been a growing appreciation that GPCR biased signaling between G protein- and β-arrestin-dependent signaling in particular is a promising method for improving drug efficacy and therapy. Orexin receptor 1 (OX1R), a member of the GPCRs, is an important drug target in the central nervous system. In this study, we identified a novel regulatory phosphorylation site (Ser-262) on OX1R that abolished its capability to interact with GRK2, but did not affect its interaction with G proteins, GRK5, or β-arrestin1/2 activation, indicating that Ser-262 is a key amino acid for OX1R internalization that contributes to induction of GRK2-dependent biased signaling via orexin A. Our findings could potentially lead to the development of new drug targets for the prevention and treatment of insomnia, narcolepsy, and substance abuse, with fewer side effects than existing therapies

Detecting Stepping-Stone Intrusion and Resisting Intruders’ Manipulation via Cross-Matching Network Traffic and Random Walk

Attackers can exploit compromised hosts to launch attacks over the Internet. This protects an intruder, placing them behind a long connection chain consisting of multiple compromised hosts. Such attacks are called stepping-stone intrusions. Many algorithms have been proposed to detect stepping-stone intrusions, but most detection algorithms are weak in resisting intruders’ session manipulation, such as chaff-perturbation. This paper proposes a novel detection algorithm: Packet Cross-Matching and RTT-based two-dimensional random walk. Theoretical proof shows network traffic cross matching can be effective in resisting attackers’ chaff attack. Our experimental results over the AWS cloud show that the proposed algorithm can resist attackers’ chaff attacks up to a chaff rate of 100%

Therapeutic potential of exosome‐based personalized delivery platform in chronic inflammatory diseases

In the inflammatory microenvironment, there are numerous exosomes secreted by immune cells (Macrophages, neutrophils, dendritic cells), mesenchymal stem cells (MSCs) and platelets as intercellular communicators, which participate in the regulation of inflammation by modulating gene expression and releasing anti-inflammatory factors. Due to their good biocompatibility, accurate targeting, low toxicity and immunogenicity, these exosomes are able to selectively deliver therapeutic drugs to the site of inflammation through interactions between their surface-antibody or modified ligand with cell surface receptors. Therefore, the role of exosome-based biomimetic delivery strategies in inflammatory diseases has attracted increasing attention. Here we review current knowledge and techniques for exosome identification, isolation, modification and drug loading. More importantly, we highlight progress in using exosomes to treat chronic inflammatory diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), atherosclerosis (AS), and inflammatory bowel disease (IBD). Finally, we also discuss their potential and challenges as anti-inflammatory drug carriers

Study on the Distribution and Community Characteristics of the Endangered Plant Picea neoveitchii Mast. in Hubei Province

In this paper, the geographical distribution, community characteristics and DBH class structure of Picea neoveitchii Mast. population were investigated and analyzed by systematical and ecological approaches. In addition, the endangered mechanism and the protection measures were put forward by analyzing the Picea neoveitchii Mast. resource distribution in Hubei Province to provide effective scientific basis for further research. The results showed that Picea neoveitchii Mast. was found in Baokang, Enshi, Shennongjia and Zhuxi of Hubei Province, there were 9 distribution points and only a wild forest was found in Baokang. The community of Baokang County was not rich in species composition and 32 species, 29 genera and 21 families were examined. Meanwhile, temperate zone was the main flora element of this community, the phaenerophytes plant was most dominant and there were few hemicryptophytes and it lacked therophytes. In this community, Picea neoveitchii Mast. was in a dominant position, including lots of treelets, so the age structure of the population was growing

Twins in Cd(1-x)Zn(x)S solid solution: Highly efficient photocatalyst for hydrogen generation from water

Cd-1 xZnxS solid solution with nano-twin structures are synthesized and exhibit superior photocatalytic activities for H-2 evolution from water under visible light irradiation (lambda >= 430 nm) without noble metal co-catalysts. Such Cd0.5Zn0.5S nanocrystals show the highest activity for hydrogen evolution with an extremely high apparent quantum yield (AQY = 43%) at 425 nm, achieving a hydrogen evolution rate of 1.79 mmol h(-1) without noble metals. The hydrogen evolution rate of 1.70 mmol h(-1) was achieved under simulated sunlight conditions (without infrared light). The "back to back" potential formed by parallel nano-twins in the Cd1-xZnxS crystals can significantly improve the separation of the photo-generated electrons/holes (preventing their recombination) thus enhancing the photocatalytic activity. Photodeposition experiments of noble metals strongly support such a mechanism. It is found that noble metals were selectively photo-deposited at central regions between the twin boundaries. The concentration of free electrons at the central region of twins was markedly higher and the twins can effectively separate the H-2 evolution sites (electrons) from oxidation reaction sites (holes)

Toward Facet Engineering of CdS Nanocrystals and Their Shape-Dependent Photocatalytic Activities

Controlling the shape or morphology of semiconductor nanocrystals is central to their enhanced physical and chemical properties. Herein, using CdS as a model photocatalyst, we demonstrate that the crystal habit of a visible-light-active semiconductor can be quantitatively controlled through synthesis kinetics. Growth rate control of {0001} facets (<i>r</i>₁) and {101̅1} facets (<i>r</i>_1′) of CdS nanocrystals was achieved by simply employing a syringe pump, which enables us to finely tune the crystal shape from nanocones, to nanofrustums, and further to nanoplates. These shape-controlled samples, showing altered proportions of {0001} to {101̅1} facets, were used to investigate the crystal-facet dependence of solar hydrogen production. The results indicate that CdS nanoplates with the largest {0001} facets showed the highest photocatalytic activity. This work not only advances our knowledge on the growth mechanism of semiconductor crystals but also illustrates a robust method to targeted crystal design of semiconductors toward optimizing their associated catalytic activities