466 research outputs found
The effect of within-crop habitat manipulations on the conservation biological control of aphids in field-grown lettuce
Within-crop habitat manipulations have the potential to increase the biological
control of pests in horticultural field crops. Wildflower strips have been shown to
increase the abundance of natural enemies, but there is little evidence to date of an
impact on pest populations. The aim of this study was to determine whether withincrop
wildflower strips can increase the natural regulation of pests in horticultural
field crops. Aphid numbers in plots of lettuce grown adjacent to wildflower strips
were compared with those in plots grown in the absence of wildflowers. The presence
of wildflower strips led to a decrease in aphid numbers on adjacent lettuce plants
during June and July, but had less impact in August and September. The decrease in
aphid numbers was greatest close to the wildflower strips and, the decrease in aphid
numbers declined with increasing distance from the wildflower strips, with little
effect at a distance of ten metres. The main natural enemies found in the crop were
those that dispersed aerially, which is consistent with data from previous studies on
cereal crops. Analysis and interpretation of natural enemy numbers was difficult due
to low recovery of natural enemies, and the numbers appeared to follow changes in
aphid abundance rather than being directly linked to the presence of wildflower
strips. Cutting the wildflower strips, to remove floral resources, had no impact on the
reduction in aphid numbers achieved during June and July, but decreased the effect
of the wildflower strips during August and September. The results suggest that
wildflower strips can lead to increased natural regulation of pest aphids in outdoor
lettuce crops, but more research is required to determine how this is mediated by
natural enemies and how the impact of wildflower strips on natural pest regulation
changes during the growing season
The weird and the wonderful – The scientific study of a miniature mummy
A human-faced oddity purported to be a ‘human baby, animal mummy or fake’ constructed in an ancient Egyptian style, was analysed at the KNH Centre for Biomedical Egyptology, University of Manchester, UK. Radiographic analysis using conventional radiography (X-ray) and computed tomography (CT) highlighted the nature of the bundle contents and identified marked similarities to mummified animal remains from ancient Egypt. Small samples were analysed using microscopy, environmental scanning electron microscopy (ESEM) and energy dispersive spectroscopy (EDS). ESEM was used to assess the homogeneity of the sample and the materials used in its construction. EDS was conducted for analysis of the elemental composition.Comparatively few miniature mummies of this type are known and they represent an intriguing area of mummy studies. The results of this research have allowed comparisons with contemporary human and animal mummies to be made.Based on residues of tin plating found on the underside of the mask, it is possible that this feature is a recent addition. Further analysis of the materials used in the construction of the artefact is required to ascertain if the mask is a contemporary feature
Fluorescence Microscopy of Hardboards
We developed a microscopic technique and used it to explore the internal structure and resin distribution in hardboards. The technique will enable us better to understand the behavior of hard-boards in use. Glycol methacrylate (JB-4 embedding medium) proved to be satisfactory for preparing 10- to 15-μm sections of hardboards with a steel knife on a sliding microtome. This thickness of sample, when viewed in transmitted near-ultraviolet light, allowed a clear visualization of hardboard internal structure and resin distribution through the board thickness. We examined wet-formed and dry-formed hardboard samples. Wet-formed high-density and medium-density boards usually showed fibers consolidated into a compact structure and a uniform resin distribution. Dry-formed high-density boards had a compact structure and medium-density boards a less compact structure; both characteristically showed uneven resin distribution
Electron Microscopy Study of Hardboards
Wet-formed and dry-formed aspen fiber hardboards are examined by transmission electron microscopy to obtain information on the hardboard internal structure and fiber-resin interactions. These factors, when related to strength and dimensional properties of hardboards, may be helpful in determining hardboard quality and suitability for structural use.During hardboard manufacturing, the wood cells break apart at the middle lamella and come in contact again when subjected to pressure during hot-pressing. Occasionally fibers remain attached in bundles. Various stages of middle lamella degradation can be observed. When totally disintegrated, middle lamella appears as dark granular material. Voids of variable size exist in medium- and high-density wet- and dry-formed hardboards. In wet-formed boards the resin (which has high electron opaqueness and appears black) shows even distribution. In dry-formed boards the resin shows uneven distribution; it is present as large accumulations in some areas but absent in others
Nax−y Hy Ti2−x Fex O4 ·nH2 O nanosheets with lepidocrocite-like layered structure synthesized by hydrothermal treatment of ilmenite sand
Nax−yHyTi2−xFexO4·nH2O nanosheets with lepidocrocite-like layered structure were produced through alkaline hydrothermal treatment at very low temperatures (130°C) from ilmenite sand. The crystal structure, morphology and optical properties were investigated by X-Ray diffraction, transmission electron microscopy, selected area electron diffraction, energy dispersive spectroscopy and UV-Vis spectroscopy. The product shows leaf-like nanosheet morphology with thickness <30 nm and lengths <1 µm. Three lepidocrocite-like titanates (Imm2 space group) with similar a and c lattice parameters but different interlayer distances (b/2) were identified. This appears to be the first preparation of lepidocrocite-like layered nanosheets by a simple, energy efficient (low temperature) and low cost (starting from mineral sand) procedure
Enhancement of titanate nanotubes dispersion for reinforcement of nylon-II nanocomposites
The purpose of the present study was to investigate the effect of titanate nanotubes (TINTs) dispersion in the mechanical properties of Nylon 11 (polyamide 11) polymer. According ,to the existing literature small amounts of TTNTs used as reinforcement in polymer matrix improve properties such as tensile strength and stiffness. However, the addition of these nanoparticles may also lead to a decrease of strength of the composite if the nanotubes are not well dispersed in the polymer matrix. In this work two different routes were investigated to enhance the disl?ersion of TTNTs used as a reinforcement of nylon matrix nanocomposites: (1) chemical functionalization with 3-arninopropyltriethoxysilane; and (2) treatment with 2 kinds of surfactant - a cationic (CTAB) and an anionic (SDS). Characterization of the nanotubes was done by infrared spectroscopy, CHN elemental analysis, measurement of the specific surface area, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. Nylon-II matrix nanocomposites were manufactured by microextrusion-microinjection and reinforced with 0.5 to 2.0 wt.-% of functionalized and surfactant treated nanotubes. Finally, mechanical and thermal properties as well as the microstructure of the nanocomposites were evaluated. The presentation will discuss the results and potential applications of these materials
Enhancement of titanate nanotubes dispersion for reinforcement of nylon-II nanocomposites
The purpose of the present study was to investigate the effect of titanate nanotubes (TINTs) dispersion in the mechanical properties of Nylon 11 (polyamide 11) polymer. According ,to the existing literature small amounts of TTNTs used as reinforcement in polymer matrix improve properties such as tensile strength and stiffness. However, the addition of these nanoparticles may also lead to a decrease of strength of the composite if the nanotubes are not well dispersed in the polymer matrix. In this work two different routes were investigated to enhance the disl?ersion of TTNTs used as a reinforcement of nylon matrix nanocomposites: (1) chemical functionalization with 3-arninopropyltriethoxysilane; and (2) treatment with 2 kinds of surfactant - a cationic (CTAB) and an anionic (SDS). Characterization of the nanotubes was done by infrared spectroscopy, CHN elemental analysis, measurement of the specific surface area, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. Nylon-II matrix nanocomposites were manufactured by microextrusion-microinjection and reinforced with 0.5 to 2.0 wt.-% of functionalized and surfactant treated nanotubes. Finally, mechanical and thermal properties as well as the microstructure of the nanocomposites were evaluated. The presentation will discuss the results and potential applications of these materials
Metabolomic biomarkers predictive of early structural lung disease in cystic fibrosis
Neutrophilic airway inflammation plays a role in early structural lung disease in cystic fibrosis (CF), but the mechanisms underlying this pathway are incompletely understood
A screening tool to identify risk for bronchiectasis progression in children with cystic fibrosis
BACKGROUND: The marked heterogeneity in cystic fibrosis (CF) disease complicates the selection of those most likely to benefit from existing or emergent treatments. OBJECTIVE: We aimed to predict the progression of bronchiectasis in preschool children with CF. METHODS: Using data collected up to 3 years of age, in the Australian Respiratory Early Surveillance Team for CF cohort study, clinical information, chest computed tomography (CT) scores, and biomarkers from bronchoalveolar lavage were assessed in a multivariable linear regression model as predictors for CT bronchiectasis at age 5–6. RESULTS: Follow‐up at 5–6 years was available in 171 children. Bronchiectasis prevalence at 5–6 was 134/171 (78%) and median bronchiectasis score was 3 (range 0–12). The internally validated multivariate model retained eight independent predictors accounting for 37% (adjusted R (2)) of the variance in bronchiectasis score. The strongest predictors of future bronchiectasis were: pancreatic insufficiency, repeated intravenous treatment courses, recurrent lower respiratory infections in the first 3 years of life, and lower airway inflammation. Dichotomizing the resulting prediction score at a bronchiectasis score of above the median resulted in a diagnostic odds ratio of 13 (95% confidence interval [CI], 6.3–27) with positive and negative predictive values of 80% (95% CI, 72%–86%) and 77% (95% CI, 69%–83%), respectively. CONCLUSION: Early assessment of bronchiectasis risk in children with CF is feasible with reasonable precision at a group level, which can assist in high‐risk patient selection for interventional trials. The unexplained variability in disease progression at individual patient levels remains high, limiting the use of this model as a clinical prediction tool
Assessment of a polygenic hazard score for the onset of pre-clinical Alzheimer’s disease
Background: With a growing number of loci associated with late-onset (sporadic) Alzheimer’s disease (AD), the polygenic contribution to AD is now well established. The development of polygenic risk score approaches have shown promising results for identifying individuals at higher risk of developing AD, thereby facilitating the development of preventative and therapeutic strategies. A polygenic hazard score (PHS) has been proposed to quantify age-specific genetic risk for AD. In this study, we assessed the predictive power and transferability of this PHS in an independent cohort, to support its clinical utility. Results: Using genotype and imaging data from 780 individuals enrolled in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, we investigated associations between the PHS and several AD-related traits, including 1) cross-sectional Aβ-amyloid (Aβ) deposition, 2) longitudinal brain atrophy, 3) longitudinal cognitive decline, 4) age of onset. Except in the cognitive domain, we obtained results that were consistent with previously published findings. The PHS was associated with increased Aβ burden, faster regional brain atrophy and an earlier age of onset. Conclusion: Overall, the results support the predictive power of a PHS, however, with only marginal improvement compared to apolipoprotein E alone
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