Feeding response of Ips paraconfusus to phloem and phloem metabolites of Heterobasidion annosum-inoculated ponderosa pine,Pinus ponderosa

In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet -cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet -cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet -cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.     

Reserves Accumulated in Non-Photosynthetic Organs during the Previous Growing Season Drive Plant Defenses and Growth in Aspen in the Subsequent Growing Season

Plants store non-structural carbohydrates (NSC), nitrogen (N), as well as other macro and micronutrients, in their stems and roots; the role of these stored reserves in plant growth and defense under herbivory pressure is poorly understood, particularly in trees. Trembling aspen (Populus tremuloides) seedlings with different NSC and N reserves accumulated during the previous growing season were generated in the greenhouse. Based on NSC and N contents, seedlings were assigned to one of three reserve statuses: Low N–Low NSC, High N–Medium NSC, or High N–High NSC. In the subsequent growing season, half of the seedlings in each reserve status was subjected to defoliation by forest tent caterpillar (Malacosoma disstria) while the other half was left untreated. Following defoliation, the effect of reserves was measured on foliar chemistry (N, NSC) and caterpillar performance (larval development). Due to their importance in herbivore feeding, we also quantified concentrations of phenolic glycoside compounds in foliage. Seedlings in Low N-Low NSC reserve status contained higher amounts of induced phenolic glycosides, grew little, and supported fewer caterpillars. In contrast, aspen seedlings in High N-Medium or High NSC reserve statuses contained lower amounts of induced phenolic glycosides, grew faster, and some of the caterpillars which fed on these seedlings developed up to their fourth instar. Furthermore, multiple regression analysis indicated that foliar phenolic glycoside concentration was related to reserve chemistry (NSC, N). Overall, these results demonstrate that reserves accumulated during the previous growing season can influence tree defense and growth in the subsequent growing season. Additionally, our study concluded that the NSC/N ratio of reserves in the previous growing season represents a better measure of resources available for use in defense and growth than the foliar NSC/N ratios.     

Rainbow guiding of the lowest-order antisymmetric Lamb mode in phononic crystal plate

The modern acoustic circuits have experienced significant progress with the development of artificial structures, including phononic crystals, metamaterials or metasurfaces. Among the most intensive topics, the reconfigurable acoustic guides are achieved through several mechanisms. In this work, we report on the rainbow guiding for the lowest-order antisymmetric Lamb(A_0) mode in a phononic crystal plate, where the linear waveguides are constituted by erecting aligned pillars either solid or hollow. We show both numerically and experimentally that the whispering gallery modes(WGMs) in the hollow pillars can be generated by the defect mode that propagates in the waveguide. Then, the reemission of A_0 mode by the WGMs to the outer lateral areas can lead to spatial control of frequency selective wave guidance called "rainbow guiding". Our approach allows for an accurate control of the wave guiding and facilitates the integration of waveguides within other devices in the acoustic circuits.     

Interspecific Comparison of Constitutive Ash Phloem Phenolic Chemistry Reveals Compounds Unique to Manchurian Ash, a Species Resistant to Emerald Ash Borer

The emerald ash borer (Agrilus planipennis, EAB) is an invasive wood-borer indigenous to Asia and is responsible for widespread ash (Fraxinus spp.) mortality in the U.S. and Canada. Resistance and susceptibility to EAB varies among Fraxinus spp., which is a result of their co-evolutionary history with the pest. We characterized constitutive phenolic profiles and lignin levels in the phloem of green, white, black, blue, European, and Manchurian ash. Phloem was sampled twice during the growing season, coinciding with phenology of early and late instar EAB. We identified 66 metabolites that displayed a pattern of variation, which corresponded strongly with phylogeny. Previously identified lignans and lignan derivatives were confirmed to be unique to Manchurian ash, and may contribute to its high level of resistance to EAB. Other compounds that had been considered unique to Manchurian ash, including hydroxycoumarins and the phenylethanoids calceolarioside A and B, were detected in closely related, but susceptible species, and thus are unlikely to contribute to EAB resistance of Manchurian ash. The distinct phenolic profile of blue ash may contribute to its relatively high resistance to EAB.     

Phenolic Chemistry of Coast Live Oak Response to <Emphasis Type="Italic">Phytophthora ramorum</Emphasis> Infection

Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant to the pathogen. In this study, the chemical basis of host resistance was investigated. Three field experiments were carried out in California between December 2004 and September 2005. The levels of nine phenolic compounds (gallic acid, catechin, tyrosol, a tyrosol derivative, ellagic acid, and four ellagic acid derivatives) extracted from the phloem of trees that had been either artificially inoculated with P. ramorum or trees putatively infected with P. ramorum (based on canker symptoms) were quantified by high-performance liquid chromatography (HPLC). Significant differences in phenolic profiles were found between phloem sampled from the active margins of cankers, healthy phloem from asymptomatic trees, and phloem sampled 60 cm away from canker sites, although the magnitude and direction of the responses was not consistent across all experiments. Concentrations of gallic acid, tyrosol, and ellagic acid showed the greatest differences in these different tissues, but varied considerably across treatments. Gallic acid and tyrosol were tested in in vitro bioassays and showed strong dose-dependent inhibitory effects against P. ramorum, P. cinnamomi, P. citricola, and P. citrophthora. These results suggest that phloem chemistry varies in response to pathogen infection in California coast live oak populations and that changes in phloem chemistry may be related to apparently resistant phenotypes observed in the field. Frances S. Ockels and Alieta Eyles contributed equally to the paper     

Comparative study of the modification of arterial pressure in adult and aged subjects treated with hemofiltration. Preliminary results

Haemodynamics modifications in 49 patients divided in two groups consisting of 21 young people (average age 43 +/- 12 yrs.) and 28 elderly people (average age 72 +/- 7 yrs.) who have undergone at least three treatments with haemofiltration for congestive cardiac decompensation and chronic renal failure have been evaluated. Systolic and diastolic blood pressure and heart rate have been monitored for each patient in a length of time of iT, T30 min., T60 min., fT. The results show a statistically significant reduction of the systolic pressure during the time interval iT-T30 min. in subjects over 65, contrary to the control group. Such preliminary results can be justified by the haemodynamic modifications correlated to the elderly process. In any case the hypothesis cited by the authors need further testing even if confirming the indication of the dialytic treatment on patients over 65 through haemofiltration techniques.     

Effect of the Closure Type on the Evolution of the Physical‐Chemical and Sensory Characteristics of a Montepulciano d'Abruzzo Rosé Wine

The present work studied the effect of the kind of closure (a screw cap, a natural cork, and 2 synthetic closures) on the evolution of the oxygen content and on the physical‐chemical and sensory characteristics of a Montepulciano d'Abruzzo rosé wine during the 1st 12 mo of bottle aging. The chemical analyses concerned the parameters more involved in the oxidative reactions (SO₂, acetaldehyde, phenols, wine color), as well as the main fermentative volatile compounds. The kind of closure influenced the oxygen content in wines, free and total SO₂ concentration, and wine color (color intensity and hue). During bottle aging, free and total SO₂ concentration was significantly and negatively correlated with absorbance at 420 nm (A420), whereas the correlations with A520 were weak. Probably, the limited extent of the variations in red color (A520), when varying SO₂ concentration, were due to the low pH of this rosé wine. No effect of the kind of closure on phenols and the main fermentative volatile compounds was observed. The wines bottled with cork closures (N trials), after 12 mo of storage, had higher color intensity and hue, measured by spectrophotometry, and were visually distinguished from the other trials for the more intense pink reflections. On the whole, under the conditions of this work, all the used closures guaranteed a good preservability to the rosè wines during the 1st year of bottle aging, and the changes in composition did not significantly affect wine sensory characteristics. Therefore, these synthetic closures can represent an alternative to the cork closures for a medium to long term bottle aging of these wines.     

The experimental identification of magnetorheological dampers and evaluation of their controllers

Magnetorheological (MR) fluid dampers are semi-active control devices that have been applied over a wide range of practical vibration control applications. This paper concerns the experimental identification of the dynamic behaviour of an MR damper and the use of the identified parameters in the control of such a damper. Feed-forward and recurrent neural networks are used to model both the direct and inverse dynamics of the damper. Training and validation of the proposed neural networks are achieved by using the data generated through dynamic tests with the damper mounted on a tensile testing machine. The validation test results clearly show that the proposed neural networks can reliably represent both the direct and inverse dynamic behaviours of an MR damper. The effect of the cylinder's surface temperature on both the direct and inverse dynamics of the damper is studied, and the neural network model is shown to be reasonably robust against significant temperature variation. The inverse recurrent neural network model is introduced as a damper controller and experimentally evaluated against alternative controllers proposed in the literature. The results reveal that the neural-based damper controller offers superior damper control. This observation and the added advantages of low-power requirement, extended service life of the damper and the minimal use of sensors, indicate that a neural-based damper controller potentially offers the most cost-effective vibration control solution among the controllers investigated.     

Distinguishing Defensive Characteristics in the Phloem of Ash Species Resistant and Susceptible to Emerald Ash Borer

We examined the extent to which three Fraxinus cultivars and a wild population that vary in their resistance to Emerald Ash Borer (EAB) could be differentiated on the basis of a suite of constitutive chemical defense traits in phloem extracts. The EAB-resistant Manchurian ash (F. mandshurica, cv. Mancana) was characterized by having a rapid rate of wound browning, a high soluble protein concentration, low trypsin inhibitor activities, and intermediate levels of peroxidase activity and total soluble phenolic concentration. The EAB-susceptible white ash (F. americana, cv. Autumn Purple) was characterized by a slow wound browning rate and low levels of peroxidase activity and total soluble phenolic concentrations. An EAB-susceptible green ash cultivar (F. pennsylvanica, cv. Patmore) and a wild accession were similar to each other on the basis of several chemical defense traits, and were characterized by high activities of peroxidase and trypsin inhibitor, a high total soluble phenolic concentration, and an intermediate rate of wound browning. Lignin concentration and polyphenol oxidase activities did not differentiate resistant and susceptible species. Of 33 phenolic compounds separated by HPLC and meeting a minimum criterion for analysis, nine were unique to Manchurian ash, five were shared among all species, and four were found in North American ashes and not in the Manchurian ash. Principal components analysis revealed clear separations between Manchurian, white, and green ashes on the basis of all phenolics, as well as clear separations on the basis of quantities of phenolics that all species shared. Variation in some of these constitutive chemical defense traits may contribute to variation in resistance to EAB in these species.