Two new species of gorgonian octocorals from the Tropical Eastern Pacific Biogeographic Region (Cnidaria,Anthozoa, Gorgoniidae)

The gorgoniid Eugorgia is exclusively an eastern Pacific genus. It has a wide geographic and bathymetric range of distribution, found from California to Perú and extends down to 65 m deep. Two new species are herein described. The morphological characters were analyzed and illustrated by light and scanning electron microscopy. Eugorgia beebei sp. n. can be distinguished by its white, ascending, sparse colony growth. Eugorgia mutabilis sp. n. can be distinguished by its white colony that changes color after collection, and the conspicuous sharp-crested disc sclerites. From a morphological point of view the new species are related to the daniana-group, the rubens-group and the siedenburgae-group of Eugorgia; their affiliations, and the proposal of a new group are discussed. These new species increases the number of species in the genus to 15, and contribute to the knowledge of the eastern Pacific octocoral biodiversity.     

Deep soil heterogeneity and fine root distribution in forests and pastures of eastern Amazonia

Little is known about deep soil heterogeneity, or its relationship with fine root distribution. Beneath a mature, closed-canopy forest of eastern Amazonia, and the pastures and secondary forests that are derived from this forest, soil soft spots and hollow chambers occur to at least 9 meters depth. We measured the vertical distribution of these soil patches, and compared chemical characteristics, mycorrhizal infection, and root density of soil soft spots with the surrounding matrix of more homogeneous soil. Soil soft spots and chambers varied little with depth, but occupied the greatest soil volume (0.8 to 1.2%) from 4 to 6 m depth in the mature forest. Soft spots had lower pH, P availability and arbuscular mycorrhizal infection, and higher K availability than surrounding soil. Root length density was 2 to 15 times higher in soft spots than in surrounding soil. In the pastures, roots were found only in soil soft spots at depths of >3 m. Pastures and secondary forest had more soil chambers in the upper meter of soil than mature forest, but were otherwise indistinguishable in their patterns of deep soil heterogeneity. Soil soft spots may be vestiges of cutter ant nest chambers, while hollow chambers are cutter ant chambers and root channels. Chambers may act as conduits for root penetration and water penetration to deep soil.Abbreviations AM arbuscular mycorrhizae - RLD root length density (root length per unit of soil volume)     

Theoretical Study of the TiO2 and MgO Surface Acidity and the Adsorption of Acids and Bases

We present ab-initio periodic Hartree–Fock calculations (crystal program) of small molecules on TiO₂ and MgO. The adsorption of the molecules may be molecular or dissociative. This depends on their acid and basic properties in the gas phase. For the molecular adsorption, the molecules are adsorbed as bases on Ti(+IV) sites, the adsorption energies correlate with the proton affinities. The dissociations on the surface correlate with the gas phase cleavages: thus, the dissociation of MeOH leads to a preferential basic cleavage (the fragment HO– is adsorbed on a Ti⁺⁴ ion and the fragment Me⁺ is adsorbed on a O²– ion of the oxide). The opposite result is obtained with MeSH. Another important factor is the adsorbate–adsorbate interaction: favorable cases are a sequence of H-bonds for the hydroxyl groups resulting from the water dissociation and the mode of adsorption for the ammonium ions. Lateral interactions also force the adsorbed CO₂ molecules to bend over the surface so that their mutual orientation resembles the geometry of the CO₂ dimer. With respect to water adsorption, MgO appears to be a basic oxide. As experimentally observed, NH₃ adsorbs preferentially on TiO₂ and CO₂ on MgO. However, this difference of reactivity should not be expressed in terms of acid vs. basic behaviour but in terms of hard and soft acidity. The MgO surface is a 'soft' acidic surface that reacts preferentially with the soft base, CO₂.     

Fine needle aspiration (FNA) in the diagnosis of soft tissue tumours; a review of 22 years experience

FNA plays an important role in preoperative diagnosis of soft tissue tumours. A close clinical/morphologic cooperation is essential. FNA should be performed on the most accessible part of the tumour, avoiding penetration of the deep portions of the tumour. Needles 0.7 mm (22 G) are recommended. For deep lesions, needles with a stylet should be used. After the FNA, tattooing of the aspiration channel is recommended, and the channel is surgically removed together with the tumour, if a sarcoma. Material from the FNA can be used for additional examinations, i.e. electron microscopy, immunohistochemistry, DNA ploidy analysis and chromosomal analysis. Those techniques are of great importance in the differential diagnosis, particularly in the paediatric small/round cell tumours. the majority of sarcomas can be defined as low grade or high grade malignant in FNA. For malignancy grading the following parameters are used: cellularity, pleomorphism, chromatin pattern, nucleolar structure, mitotic figures and necroses. Cytodiagnostic details of the most common soft tissue tumours and their differential diagnoses are presented.     

Local Recurrence of Soft Tissue Sarcoma Revisited: Is there a Role for “Selective” Radiation?

BackgroundRadiation therapy (RT) is often utilized in cases of high-grade soft tissue sarcoma (STS), but there remain situations where treatment is with surgical excision alone. Our goals were to determine (1) the local recurrence (LR) rate with and without perioperative RT and (2) associations between local recurrence, patient, tumor, and treatment variables.MethodsWe performed a retrospective review of 165 consecutive STS patients. A Cox proportional hazards model was used to investigate variables associated with local recurrence.ResultsLR occurred in 15/78 (19%) without RT, 4/29 (14%) with postoperative RT, and 0/58 with preoperative RT (p=0.002). We found increased rates of local recurrence at 24 months for myxofibrosarcoma (p=0.001) and no-RT (p=0.003). Myxofibrosarcoma accounted for 33 (20%) of the study patients and 12 (63%) of the local recurrences.ConclusionThe LR rate in patients treated with surgery alone was disproportionately attributable to myxofibrosarcoma (11/23 cases, 48%). Other subtypes demonstrated a lower rate of LR in the absence of RT (4/55 cases, 7%), and no LR occurred when final margins were >2 mm. In certain circumstances treatment with a negative margin surgical resection followed by close observation is justifiable. RT is effective and should continue to be considered routinely in myxofibrosarcoma or when surgical margins are inadequate. Level of Evidence: III     

Role of Soft Matter in the Sandwich Vein of Dragonfly Wing in Its Configuration and Aerodynamic Behaviors

The microstructure of the main longitudinal veins of the dragonfly wing and the aerodynamic behaviors of the wing were investigated in this paper.The microstructure of longitudinal vein presents two circumferential chitin layers and a protein-fiber soft layer.The dragonfly wing is corrugated due to the spatial arrangement of longitudinal veins.It was found that the corrugation angle could significantly influence the lift/drag ratio across a range of attack angles by the wind tunnel experiments.The results of the finite element analysis indicate that the protein soft layer of vein facilitates the change of the corrugation angle by allowing substantial relative twisting deformation between two neighboring veins,which is not possible in veins without a soft sandwich layer.     

1-辛烯-3-醇防治采后桃果实软腐病的作用

【目的】桃果实易受匍枝根霉(Rhizopus stolonifer)侵染引起软腐病,导致果实采后腐烂损失严重。目前人工合成的化学杀菌剂是控制桃果实采后病害的主要方法,但长期使用容易带来食品安全隐患、病原菌抗药性和环境污染等问题。通过研究生物源抑菌成分1-辛烯-3-醇对桃果实软腐病的控制作用,为减少化学农药使用和控制采后桃果实软腐病提供理论基础。【方法】使用1-辛烯-3-醇熏蒸接种匍枝根霉(R.stolonifer)后的桃果实,对果实抗病相关基因表达和酶活性进行测定。通过离体试验,研究1-辛烯-3-醇熏蒸对匍枝根霉(R.stolonifer)菌丝和孢子的影响。【结果】55.80μg/mL 1-辛烯-3-醇熏蒸处理可以显著降低桃果实的发病率和病斑直径(P<0.05),提高几丁质酶(chitinase,CHI)和β-1,3葡聚糖酶(β-1,3-glucanase,GLU)的活性以及病程相关基因非表达子1(nonexpressor of pathogenesis-related protein 1,NPR1)、病程相关蛋白1(pathogenesis-related protein 1,PR1)、CHI和GLU的基因表达量。离体试验结果显示,1-辛烯-3-醇可抑制平板上匍枝根霉(R.stolonifer)菌丝的生长,使菌丝体细胞结构遭到破坏,同时显著降低麦角固醇含量(P<0.05),抑制孢囊孢子的萌发和芽管伸长,并通过破坏孢子的膜结构,引起活性氧(reactive oxygen species,ROS)暴发与线粒体损伤。【结论】以上结果证实,1-辛烯-3-醇熏蒸处理不仅能直接破坏匍枝根霉(R.stolonifer)的菌丝与孢子,还可通过诱导桃果实的系统获得性抗性(systemic acquired resistance,SAR)抑制采后软腐病的蔓延。     

生物实验学习软环境的创设

以情境认知和学习理论为指导,结合生物实验学习实际运用的成效,阐述了生物实验学习软环境创设的操作要领。     

Evolution of dispersal in spatially and temporally variable environments: The importance of life cycles

Spatiotemporal variability of the environment is bound to affect the evolution of dispersal, and yet model predictions strongly differ on this particular effect. Recent studies on the evolution of local adaptation have shown that the life cycle chosen to model the selective effects of spatiotemporal variability of the environment is a critical factor determining evolutionary outcomes. Here, we investigate the effect of the order of events in the life cycle on the evolution of unconditional dispersal in a spatially heterogeneous, temporally varying landscape. Our results show that the occurrence of intermediate singular strategies and disruptive selection are conditioned by the temporal autocorrelation of the environment and by the life cycle. Life cycles with dispersal of adults versus dispersal of juveniles, local versus global density regulation, give radically different evolutionary outcomes that include selection for total philopatry, evolutionary bistability, selection for intermediate stable states, and evolutionary branching points. Our results highlight the importance of accounting for life‐cycle specifics when predicting the effects of the environment on evolutionarily selected trait values, such as dispersal, as well as the need to check the robustness of model conclusions against modifications of the life cycle.