Land management shapes drought responses of dominant soil microbial taxa across grasslands.

Soil microbial communities are dominated by a relatively small number of taxa that may play outsized roles in ecosystem functioning, yet little is known about their capacities to resist and recover from climate extremes such as drought, or how environmental context mediates those responses. Here, we imposed an in situ experimental drought across 30 diverse UK grassland sites with contrasting management intensities and found that: (1) the majority of dominant bacterial (85%) and fungal (89%) taxa exhibit resistant or opportunistic drought strategies, possibly contributing to their ubiquity and dominance across sites; and (2) intensive grassland management decreases the proportion of drought-sensitive and non-resilient dominant bacteria-likely via alleviation of nutrient limitation and pH-related stress under fertilisation and liming-but has the opposite impact on dominant fungi. Our results suggest a potential mechanism by which intensive management promotes bacteria over fungi under drought with implications for soil functioning.

Study of energetic properties of different tree organs in six Olea europaea L. cultivars.

Pruning is an important horticultural practice for the management of olive orchards (Olea europaea L.) that generates a considerable amount of residues every year. Olive orchards are increasingly expanding beyond the Mediterranean Basin to new growing Countries (Australia, California, Argentina, Chile and Uruguay) and this will certainly lead to larger availability of pruning material. Currently, the interest in use of olive tree pruning residues for energy purposes is increasing but unfortunately, the information on the differences among organs of the tree, in terms of calorific value and ash content, is scarce. Another unknown aspect is the effect of cultivar vigour on dry matter partition among different tree organs, these are important traits to establish the energetic quality of pruning residues. The aim of this research was to study energetic aspects of six olive cultivars, largely grown in the Sicilian olive industry and characterized by different vigour. The trees taken into consideration in the study were selected in an experimental orchard to avoid any effect due to differences in environmental conditions and management. The energetic characteristics, calorific value and ash content, were evaluated for the various tree organs particularly shoots, leaves and branches; also root system was evaluated, although the roots can only be used once the trees are uprooted. Significant differences were observed in the calorific values among the different tree organs and the cultivars. Regarding the ash, shoots and leaves showed the highest content with respect to the other organs, thus causing a possible tendency in slagging with fouling and corrosion of boiler components.

Does the location of the arterial input function affect quantitative CTP in patients with vasospasm?

BACKGROUND AND PURPOSE: In recent years, there has been increasing use of CTP imaging in patients with aneurysmal SAH to evaluate for vasospasm. Given the critical role of the arterial input function for generation of accurate CTP data, several studies have evaluated the effect of varying the arterial input function location in patients with acute stroke. Our aim was to determine the effect on quantitative CTP data when the arterial input function location is distal to significant vasospasm in patients with aneurysmal SAH. MATERIALS AND METHODS: A retrospective study was conducted of patients with aneurysmal SAH admitted from 2005 to 2011. Inclusion criteria were the presence of at least 1 anterior cerebral artery or MCA vessel with a radiologically significant vasospasm and at least 1 of these vessels without vasospasm. We postprocessed each CTP dataset 4 separate times by using standardized methods, only varying the selection of the arterial input function location in the anterior cerebral artery and MCA vessels. For each of the 4 separately processed examinations for each patient, quantitative data for CBF, CBV, and MTT were calculated by region-of-interest sampling of the vascular territories. Statistical analysis was performed by using a linear mixed-effects model. RESULTS: One hundred twelve uniquely processed CTP levels were analyzed in 28 patients (mean age, 52 years; 24 women and 4 men) recruited from January 2005 to December 2011. The average Hunt and Hess scale score was 2.89 ± 0.79. The average time to CTP from initial presentation was 8.2 ± 5.1 days. For each vascular territory (right and left anterior cerebral artery, MCA, posterior cerebral artery), there were no significant differences in the quantitative CBF, CBV, and MTT generated by arterial input function locations distal to significant vasospasm compared with nonvasospasm vessels (P > .05). CONCLUSIONS: Arterial input function placement distal to significant vasospasm does not affect the quantitative CTP data in the corresponding vascular territory or any other vascular territory in aneurysmal SAH.

Compositional divergence and convergence in arbuscular mycorrhizal fungal communities.

In spite of the controversy that they have generated, neutral models provide ecologists with powerful tools for creating dynamic predictions about beta-diversity in ecological communities. Ecologists can achieve an understanding of the assembly rules operating in nature by noting when and how these predictions are met or not met. This is particularly valuable for those groups of organisms that are challenging to study under natural conditions (e.g., bacteria and fungi). Here, we focused on arbuscular mycorrhizal fungal (AMF) communities and performed an extensive literature search that allowed us to synthesize the information in 19 data sets with the minimal requisites for creating a null hypothesis in terms of community dissimilarity expected under neutral dynamics. In order to achieve this task, we calculated the first estimates of neutral parameters for several AMF communities from different ecosystems. Communities were shown either to be consistent with neutrality or to diverge or converge with respect to the levels of compositional dissimilarity expected under neutrality. These data support the hypothesis that divergence occurs in systems where the effect of limited dispersal is overwhelmed by anthropogenic disturbance or extreme biological and environmental heterogeneity, whereas communities converge when systems have the potential for niche divergence within a relatively homogeneous set of environmental conditions. Regarding the study cases that were consistent with neutrality, the sampling designs employed may have covered relatively homogeneous environments in which the effects of dispersal limitation overwhelmed minor differences among AMF taxa that would lead to environmental filtering. Using neutral models we showed for the first time for a soil microbial group the conditions under which different assembly processes may determine different patterns of beta-diversity. Our synthesis is an important step showing how the application of general ecological theories to a model microbial taxon has the potential to shed light on the assembly and ecological dynamics of communities.

Island organization of TiO2 hierarchical nanostructures induced by surface wetting and drying.

We report on the reorganization and bundling of titanium oxide nanostructured layers, induced by wetting with different solvents and subsequent drying. TiO(2) layers are deposited by pulsed laser deposition and are characterized by vertically oriented, columnar-like structures resulting from assembling of nanosized particles; capillary forces acting during evaporation induce bundling of these structures and lead to a micrometer-size patterning with statistically uniform islands separated by channels. The resulting surface is characterized by a hierarchical, multiscale morphology over the nanometer-micrometer length range. The structural features of the pattern, i.e., characteristic length, island size, and channel width, are shown to depend on properties of the liquid (i.e., surface tension) and thickness and density of the TiO(2) layers. The studied phenomenon permits the controlled production of multiscale hierarchically patterned surfaces of nanostructured TiO(2) with large porosity and large surface area, characterized by superhydrophilic wetting behavior without need for UV irradiation.

Euclidean geometry explains why lengths allow precise body mass estimates in terrestrial invertebrates: the case of oribatid mites.

Indirect measures of soil invertebrate body mass M based on equations relating the latter to body length (l) are becoming increasingly used due to the required painstaking laboratory work and the technical difficulties involved in obtaining some thousands of reliable weight estimates for animals that can be very small. The implicit assumption of such equations is that dM/dV=delta, where V is body volume and delta is a constant density value. Classical Euclidean scaling implies that V is proportional to l(3) proportional to M. One may thus derive M from l when the latter can provide a good estimate of V and the assumption of a constant delta is respected. In invertebrates, equations relating weight to length indicate that the power model always provides the best fit. However, authors only focused on the empirical estimation of slopes linking the body mass to the length measure variables, sometimes fitting exponential and linear models that are not theoretically grounded. This paper explicates how power laws derive from fundamental Euclidean scaling and describes the expected allometric exponents under the above assumptions. Based on the classical Euclidean scaling theory, an equivalent sphere is defined as a theoretical sphere with a volume equal to that of the organism whose body mass must be estimated. The illustrated application to a data set on soil oribatid mites helps clarify all these issues. Lastly, a general procedure for more precise estimation of M from V and delta is suggested.

Electronic structure of cluster assembled nanostructured TiO(2) by resonant photoemission at the Ti L(2,3) edge.

The electronic structure of cluster assembled nanostructured TiO(2) thin films has been investigated by resonant photoemission experiments with photon energies across the Ti L(2,3) edge. The samples were produced by supersonic cluster beam deposition with a pulsed microplasma cluster source. The valence band shows resonance enhancements in the binding energy region between 4 and 8 eV, populated by O 2p and hybridized Ti 3d states, and in the region about 1 eV below the Fermi level associated with defects related Ti 3d states. The data show that in as-deposited films Ti atoms are mainly fully (sixfolds) coordinated to oxygen atoms in octahedral symmetry and only a small fraction is in a broken symmetry environment. Since resonant photoemission is closely linked to the local electronic and structural configurations around the Ti atom, it is possible to correlate the resonant photoemission intensity and lineshape with the presence of defects of the films and with the degree of hybridization between the titanium and oxygen atoms.

Nanocrystalline metal/carbon composites produced by supersonic cluster beam deposition.

In this work we show that supersonic cluster beam deposition is a viable method for the synthesis of nanocrystalline metal/carbon composites. By assembling carbon and metallic clusters seeded in a supersonic beam, we have grown films consisting of metal nanoparticles embedded in a nano-structured carbon matrix. Samples containing 3d transition metals (Ti, Ni) and noble metals (Au, Pd, Pt) with different metal abundances, particle size and dilution have been characterized by transmission electron microscopy. The influence of different metals on the structure of the carbon matrix has been investigated. Spatially resolved ultraviolet photoemission electron spectroscopy showed substantial surface oxidation of 3d transition metal clusters. On a micrometric scale, the spatial distribution of the metallic nanoparticles appeared to be homogeneous.

Raman investigation of the ionic liquid N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide and its mixture with LiN(SO2CF3)2.

A preliminary Raman investigation of the ionic liquid N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR(13)TFSI) and its 2/1 complex with the lithium salt LiN(SO(2)CF(3))(2) is reported. The study was performed over a temperature range extending from -100 to +60 degrees C, i.e., with PYR(13)TFSI in the crystalline and melt states. For comparison purposes, the study was extended to PYR(13)I, which is the precursor used in the synthesis of PYR(13)TFSI.

Impact of prenatal screening on the birth status of fetuses with Down syndrome at an urban hospital, 1972-1994.

PURPOSE: This hospital-based study has determined the change over time (1972-1974 and 1979-1994) in the methods of prenatal detection of fetuses with Down syndrome and the impact of elective termination on the portion that were liveborn. METHODS: Using a malformations surveillance program, all 265 affected fetuses and infants were identified among 161,560 births and elective terminations during the aforementioned period at Brigham and Women's Hospital in Boston, MA. RESULTS: From 1972 to 1974, Down syndrome was not diagnosed in any affected infants prenatally. In the early 1980s, amniocentesis was the primary method of diagnosis; later, maternal serum screening and ultrasonography were as likely to be the first method of detection. Most couples (86%) elected to terminate pregnancies with affected fetuses. CONCLUSIONS: The effect of prenatal detection and the choice of elective termination produced a significant decrease, between 1972 and 1994, in the portion of fetuses with Down syndrome who were liveborn.

Postmortem stability of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase in rat striatum.

The stability of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase was measured in homogenates of rat striatal tissue frozen from 0 to 24 h postmortem. ATPase, GTPase, and Mg2+-dependent guanylate cyclase activities showed no significant change over this period. Mn2+-dependent guanylate cyclase activity was stable for 10 h postmortem. Basal and dopamine-stimulated adenylate cyclase activity decreased markedly during the first 5 h. However, when measured in washed membrane preparations, these adenylate cyclase activities remained stable for at least 10 h. Therefore, the postmortem loss of a soluble activator, such as GTP, may decrease the adenylate cyclase activity in homogenates. These results are not consistent with an earlier suggestion that there is a postmortem degradation of the enzyme itself. Other kinetic parameters of dopamine-sensitive adenylate cyclase can also be measured independently of postmortem changes. Thus, it is possible to investigate kinetic parameters of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase in human brain obtained postmortem.

Pharmacological studies with an alkylating narcotic agonist, chloroxymorphamine, and antagonist, chlornaltrexamine.

The 6-bis(2)chloroethyl)amino derivatives of oxymorphone and naltrexone, chloroxymorphamine (COA) and chlornaltrexamine (CNA), respectively, produce an irreversible inhibition of [3H]naltrexone binding to mouse brain homogenates. Intracerebroventricular (i.c.v.) injection of COA (4 nmol/mouse) elicits analgesia which lasts 4 times longer than analgesia produced by equimolar and equieffective dose of oxymorphone. The analgesia induced by COA can be reversed and blocked by naloxone. Injections of both COA and CNA i.c.v. antagonize morphine-induced analgesia for 3 days. Similarly, when [3H]naltrexone binding is measured in brains from mice pretreated i.c.v. with COA or CNA, there is a significant decrease in total specific binding for 3 days after pretreatment. These data suggest that CNA and COA alkylate the opioid receptors to produce antagonist and agonist-antagonist effects, respectively. The implications of these findings are discussed with respect to their effect on our perception of the opioid receptor-narcotic agonist interaction and the mechanisms of tolerance and dependence.

Chloroxymorphamine, and opioid receptor site-directed alkylating agent having narcotic agonist activity.

Chloroxymorphamine, the 6beta-N,N-bis(2-chloroethyl) derivative of oxymorphone, is a potent nonequilibrium narcotic agonist in the longitudinal muscle preparation of guinea pig ileum. The corresponding naltrexone analog,chlornaltrexamine, is a potent nonequilibrium antagonist of morphine. These receptor sitedirected alkylating agents possess considerable potenial as pharmacologic and biochemical probes of apoid receptors.

Synthesis and pharmacologic characterization of an alkylating analogue (chlornaltrexamine) of naltrexone with ultralong-lasting narcotic antagonist properties.

Chlornaltrexamine (CNA) produces ultralong-lasting (3--6 days) narcotic antagonism in mice and persistent stereospecific binding to rat-brain homogenate. Protection studies in mice suggest that CNA mediates its narcotic antagonist effects by interacting with the same receptors that are occupied by naloxone. A single icv dose of CNA also has been found to inhibit the development of physical dependence in mice for at least 3 days. These studies suggest that CNA exerts its sustained effects by selective covalent association with opioid receptors.

Mechanisms of genetic resistance to Friend virus leukemia. III. Susceptibility of mitogen-responsive lymphocytes mediated by T cells.

Friend leukemia virus (FV) suppressed the proliferative responses of spleen, lymph node, marrow, and thymus cell populations to various T- and B-cell mitogens. Cells taken from mice, e.g. BALB/c genetically susceptible to leukemogenesis in vivo were much more susceptible to suppression of mitogenesis in vitro than similar cells from genetically resistant mice, e.g., C57BL/6. Nylon wool-purified splenic T cells from BALB/c and C3H mice lost susceptibility to FV-induced suppression of mitogenesis but became suppressible by addition of 10% unfiltered spleen cell. Thus, FV mediates in vitro suppression of lymphocyte proliferation indirectly by "activating" a suppressor cell. The suppressor cell adhered to nylon wool but not to glass wool or rayon wool columns. Pretreatment of spleen cells with carbonyl iron and a magnet did not abrogate the suppressor cell function. Suppressor cells were not eliminated by treatment with rabbit antimouse immunoglobulin (7S) and complement (C). However, high concentrations of anti-Thy-1 plus C destroyed suppressor cells of the spleen; thymic suppressor cells were much more susceptible to anti-Thy-1 serum. Nude athymic mice were devoid of suppressor cells and their B-cell proliferation was relatively resistant to FV-induced suppression in vitro. The suppressor cells in the thymus (but not in the spleen) were eliminated by treatment of mice with cortisol. Thus, FV appears to mediate its suppressive effect on mitogen-responsive lymphocytes by affecting "T-suppressor cells." Spleen cells from C57BL/6 mice treated with 89Sr to destroy marrow-dependent (M) cells were much more suppressible by FV in virto than normal C57BL/6 spleen cells. However, nylon-filtered spleen cells of 89Sr-treated C57BL/6 mice were resistant to FV-induced suppression in vitro, indicating that the susceptibility of spleen cells from 89Sr-treated B6 mice is also mediated by suppressor cells. Normal B6 splenic T cells were rendered susceptible to FV-induced suppression of mitogenesis by addition of 10% spleen cells from 89Sr-treated B6 mice. Thus, M cells appear to regulate the numbers and/or functions of T-suppressor cells which in turn mediate the immunosuppressive effects of FV in vitro. Neither mitogen-responsive lymphocytes nor T-suppressor cells are genetically resistant or susceptible to FV. The genetic resistance to FV is apparently a function of M cells, both in vitro as well as in vivo.