Morphology and Anatomy of Foliar Nectaries and Associated Leaves in Mallotus (Euphorbiaceae)

The morphology and anatomy of the foliar nectaries and associated leaves offour species of Mallotus (Euphorbiaceae) were studied. Light microscopic observations of paraffin- and plastic-embedded specimens were complemented with scanning electron micrographs. Leaf anatomy of the four species is typical of large mesophytic plants. Aattened foliar nectaries are shown to be composed of specialized epidermal cells. The nonvascularized nectaries consist of narrow columnar cells each with a large nucleus, numerous vacuoles, and dense cytoplasm. Subglandular parenchyma cells have more pronounced nuclei, more vacuoles and denser cytoplasm than do typical laminar parenchyma. Structurally, these nectaries are similar to those found in other taxa of Euphorbiaceae and in other families of flowering plants. Brief field observations confirmed that ants are readily attracted to the nectar and probably function in a mutualistic relationship with the plants. The actual mechanism of nectar secretion was not studied

Effect of wind speed on the size distribution of gel particles in the sea surface microlayer: insights from a wind–wave channel experiment

Gel particles, such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP), are important organic components in the sea surface microlayer (SML). Here, we present results on the effect of different wind speeds on the accumulation and size distribution of TEP and CSP during a wind wave channel experiment in the Aeolotron. Total areas of TEP (TEPSML) and CSP (CSPSML) in the surface microlayer were exponentially related to wind speed. At wind speeds    8 m s−1. Wind speeds  >  8 m s−1 also significantly altered the size distribution of TEPSML in the 2–16 µm size range towards smaller sizes. The response of the CSPSML size distribution to wind speed varied through time depending on the biogenic source of gels. Wind speeds  >  8 m s−1 decreased the slope of CSPSML size distribution significantly in the absence of autotrophic growth. For the slopes of TEP and CSP size distribution in the bulk water, no significant difference was observed between high and low wind speeds. Changes in spectral slopes between high and low wind speed were higher for TEPSML than for CSPSML, indicating that the impact of wind speed on size distribution of gel particles in the SML may be more pronounced for TEP than for CSP, and that CSPSML are less prone to aggregation during the low wind speeds. Addition of an E. huxleyi culture resulted in a higher contribution of submicron gels (0.4–1 µm) in the SML at higher wind speed ( >  6 m s−1), indicating that phytoplankton growth may potentially support the emission of submicron gels with sea spray aerosol

Life fingerprints of nuclear reactions in the body of animals

Nuclear reactions are a very important natural phenomenon in the universe. On the earth, cosmic rays constantly cause nuclear reactions. High energy beams created by medical devices also induce nuclear reactions in the human body. The biological role of these nuclear reactions is unknown. Here we show that the in vivo biological systems are exquisite and sophisticated by nature in influence on nuclear reactions and in resistance to radical damage in the body of live animals. In this study, photonuclear reactions in the body of live or dead animals were induced with 50-MeV irradiation. Tissue nuclear reactions were detected by positron emission tomography (PET) imaging of the induced beta+ activity. We found the unique tissue "fingerprints" of beta+ (the tremendous difference in beta+ activities and tissue distribution patterns among the individuals) are imprinted in all live animals. Within any individual, the tissue "fingerprints" of 15O and 11C are also very different. When the animal dies, the tissue "fingerprints" are lost. The biochemical, rather than physical, mechanisms could play a critical role in the phenomenon of tissue "fingerprints". Radiolytic radical attack caused millions-fold increases in 15O and 11C activities via different biochemical mechanisms, i.e. radical-mediated hydroxylation and peroxidation respectively, and more importantly the bio-molecular functions (such as the chemical reactivity and the solvent accessibility to radicals). In practice biologically for example, radical attack can therefore be imaged in vivo in live animals and humans using PET for life science research, disease prevention, and personalized radiation therapy based on an individual's bio-molecular response to ionizing radiation

Comunidad de cianobacterias en los sedimentos del estuario del río Perla en China

Cyanobacterial community diversity in the sediment of the Pearl River Estuary in China was evaluated in this study by denaturing gradient gel electrophoresis (DGGE) during the wet and dry seasons. Nucleotide sequences obtained from DGGE bands were classified into five cyanobacterial clusters, including Synechococcus, Cyanobium, Chroococcus, Prochlorales and Tolypothrix. Synechococcus was identified as the dominant cyanobacterial group in the sediment samples; its distribution varied from the inner estuary to the outer estuary, with a wide range of salinity adaptation. Observed patterns of cyanobacterial communities changed markedly between sampling sites and seasons, suggesting that most cyanobacteria were not delivered via fresh water. Canonical correspondence analysis was conducted to determine the relationship between environmental variables and bacterial community structures during the dry season. The results suggested that the cyanobacterial community was significantly influenced by pH, salinity, PO4-P and NO3-N in sediments.La diversidad de la comunidad de cianobacterias en el sedimento del estuario del río Perla en China fue evaluada en este estudio por electroforesis en gel de gradiente desnaturalizante (DGGE) durante las estaciones húmeda y seca. Las secuencias de nucleótidos obtenidas de bandas DGGE se clasificaron en cinco grupos de cianobacterias, incluyendo Synechococcus, Cyanobium, Chroococcus, Prochlorales y Tolypothrix. Synechococcus fue identificado como el grupo dominante de cianobacterias en las muestras de sedimento, su distribución varió desde la parte interna del estuario hasta la externa, con un amplio rango de adaptación a la salinidad. Los patrones observados de las comunidades de cianobacterias cambiaron marcadamente entre diferentes sitios de muestreo en diferentes estaciones del año y sugirió que la mayoría de las cianobacterias no provenían a través del agua dulce. Se realizó un análisis de correspondencia canónica (CCA) para determinar la relación entre variables ambientales y estructuras de las comunidades bacterianas durante la estación seca. Los resultados sugirieron que las distintas comunidades de cianobacterias estaban significativamente influenciadas por el pH, salinidad, PO4-P y NO3-N en los sedimentos

Effect of temperature on the accumulation of marine biogenic gels in the surface microlayer near the outlet of nuclear power plants and adjacent areas in the Daya Bay, China

The surface microlayer (SML) in marine systems is often characterized by an enrichment of biogenic, gel-like particles, such as the polysaccharide-containing transparent exopolymer particles (TEP) and the protein-containing Coomassie stainable particles (CSP). This study investigated the distribution of TEP and CSP, in the SML and underlying water, as well as their bio-physical controlling factors in Daya Bay, an area impacted by warm discharge from two Nuclear power plants (Npp’s) and aquaculture during a research cruise in July 2014. The SML had higher proportions of cyanobacteria and of pico-size Chl a contrast to the underlayer water, particularly at the nearest outlet station characterized by higher temperature. Diatoms, dinoflagellates and chlorophyll a were depleted in the SML. Both CSP and TEP abundance and total area were enriched in the SML relative to the underlying water, with enrichment factors (EFs) of 1.5–3.4 for CSP numbers and 1.32–3.2 for TEP numbers. Although TEP and CSP showed highest concentration in the region where high productivity and high nutrient concertation were observed, EFs of gels and of dissolved organic carbon (DOC) and dissolved acidic polysaccharide (> 1 kDa), exhibited higher values near the outlet of the Npp’s than in the adjacent waters. The positive relation between EF’s of gels and temperature and the enrichment of cyanobacteria in the SML may be indicative of future conditions in a warmer ocean, suggesting potential effects on adjusting phytoplankton community, biogenic element cycling and air-sea exchange processe

Exploiting Delay Budget Flexibility for Efficient Group Delivery in the Internet of Things

Further accelerated by the Internet of Things (IoT) concept, various devices are being continuously introduced into diverse application scenarios. To achieve unattended updates of IoT smart object(s), there remains a challenging problem concerning how to efficiently deliver messages to specific groups of target nodes, especially considering node mobility. In this paper, the relay selection problem is investigated on the basis of directional movement with randomness (e.g. typically associated with the searching or migrating behaviour of animals). Unlike numerous works tackling one-to-one communication, we focus on efficient group delivery (one-to-many). A two-level delay budget model is considered to reflect the flexibility of delay tolerance, which brings potential efficiency gains for group delivery compared with using a single budget boundary. Following the description of the system model, a combinatorial bi-objective optimisation problem is formulated and solutions are proposed. Simulation results show that the greedy algorithm can achieve comparable performance to an evolutionary algorithm when the delivery satisfaction outweighs efficiency. Furthermore, we show that our proposed greedy scheme can outperform the state-of-theart when the delivery efficiency becomes increasingly important

A review in rational design of graphene toward advanced Li–S batteries

For lithium–sulfur (Li–S) batteries, the problems of polysulfides shuttle effect, slow dynamics of sulfur species and growth of lithium dendrite during charge/discharge processes have greatly impeded its practical development. Of core importance to advance the performances of Li–S batteries lies in the selection and design of novel materials with strong polysulfides adsorption ability and enhanced redox electrocatalytic behavior. Graphene, affording high electrical conductivity, superior carrier mobility, and large surface area, has presented great potentials in improving the performances of Li–S cells. However, the properties of intrinsic graphene are far enough to achieve the multiple management toward electrochemical catalysis of energy storage systems. In addition, a general and objective understanding of its role in Li–S systems is still lacking. Along this line, we summarize the design routes from three aspects, including defect engineering, dimension adjustment, and heterostructure modulation, to perfect the graphene properties. Thus-synthesized graphene materials are explored as multifunctional electrocatalysts targeting high-efficiency and long-lifespan Li–S batteries, based on which the regulating role of graphene is comprehensively analyzed. This project provides a perspective on the effective engineering management of graphene materials to boost Li–S chemistry, meanwhile promote the practical application process for graphene materials