Predicting aboveground biomass in Arctic landscapes using very high spatial resolution satellite imagery and field sampling

Remote sensing based biomass estimates in Arctic areas are usually produced using coarse spatial resolution satellite imagery, which is incapable of capturing the fragmented nature of tundra vegetation communities. We mapped aboveground biomass using field sampling and very high spatial resolution (VHSR) satellite images (QuickBird, WorldView-2 and WorldView-3) in four different Arctic tundra or peatland sites with low vegetation located in Russia, Canada, and Finland. We compared site-specific and cross-site empirical regressions. First, we classified species into plant functional types and estimated biomass using easy, non-destructive field measurements (cover, height). Second, we used the cover/height-based biomass as the response variable and used combinations of single bands and vegetation indices in predicting total biomass. We found that plant functional type biomass could be predicted reasonably well in most cases using cover and height as the explanatory variables (adjusted R² 0.21–0.92), and there was considerable variation in the model fit when the total biomass was predicted with satellite spectra (adjusted R² 0.33–0.75). There were dissimilarities between cross-site and site-specific regression estimates in satellite spectra based regressions suggesting that the same regression should be used only in areas with similar kinds of vegetation. We discuss the considerable variation in biomass and plant functional type composition within and between different Arctic landscapes and how well this variation can be reproduced using VHSR satellite images. Overall, the usage of VHSR images creates new possibilities but to utilize them to full potential requires similarly more detailed in-situ data related to biomass inventories and other ecosystem change studies and modelling.     

Testing the homogenizing effect of low copper sulfate concentrations on the size distribution of Portulaca oleracea seedlings in vitro

Traditionally, toxicological bioassays rely upon the differences in mean-based statistical tests between the exposed and unexposed plants, and exceptional plant individuals are treated as statistical outliers. Recently, low toxicant concentrations have been observed to affect gene regulation in exposed plant stands and to change the frequency of the largest individuals even if mean plant size remains unchanged. In this paper, we present the results that the latter phenomenon is not restricted to a single toxicant and plant species. Our data analysis consists of two statistical methods that may be of general interest. We utilized the one-tailed Moses extreme reactions test by comparing exposed groups to control plants with and without the trimming of a certain amount of potential outliers from both treatments compared. We also propose that Mann-Whitney U or other tests at ordinal scale can be utilized to analyze if the largest plant individuals in exposed and control treatments come from a single ‘survivor’ population. We conclude that the results supported the hypothesis that very low toxicant concentrations may have ecological effects on fast-growing plant species. Finally, we discuss the limitations of the statistical methods currently in use.     

Phosphorescent metalloporphyrins as labels in time-resolved luminescence microscopy: effect of mounting on emission intensity

In this study, we present an investigation of the effects of mounting media on the phosphorescence of metalloporphyrin stained microscopy samples. The samples were: (1) Platinum(II) coproporphyrin (=PtCP) stained porous Sephadex beads; (2) compact polystyrene microspheres coated with IgG-PtCP conjugate; and (3) immunocytochemically labeled human peripheral blood neutrophils. The human neutrophils in a mixed leukocyte population were fixed, permeabilized, and then immunolabeled with PtCP conjugate of monoclonal mouse IgG directed to the intracellular antigen myeloperoxidase. The samples were mounted in twelve different mounting media and studied with quantitative time-resolved luminescence imaging microscopy with respect to the intensity and stability of the phosphorescence signal. The results indicate that microscopy samples stained with PtCP exhibit the brightest phosphorescence emission in non-mounted form or when mounted in non-aqueous permanent mounting media.     

The influence of heat treatment and finishing on the mechanical and dielectric properties of glass fabric-epoxy resin laminar composites

The aim of this investigation was to define the optimum conditions of obtaining glass fabric-epoxy resin laminar composites with mechanical and dielectric properties that satisfy the quality needed for production of printed circuit boards for microelectronics. Commercial materials: glass woven fabric, different types of silane finish and epoxy resin were the starting materials in obtaining composites. The conditions needed for the thermal removal of the original size from glass fabric were investigated. The optimal heat treatment should be performed at temperatures less than 550 °C, while cooling rates should be as low as possible. In this manner, the fabric has less than 0.1% of residual size, and the mechanical properties remain satisfactory. Different types of adhesion promoters based on silanes were applied on heat-treated glass fabric as finishes. The quality of the composite material made of thermally and chemically treated glass fabric and epoxy resin was controled by measuring the tensile and dielectric strength of the composite. Depending on which properties of composite are of primary concern, mechanical or dielectric, a finish with an amino functional group and lower heat-treatment temperature or epoxy-modified coatings and higher heat-treatment temperature should be used for obtaining glass-fabric epoxy resin laminar composites.     

In vitro and in vivo investigation of taste-masking effectiveness of Eudragit E PO as drug particle coating agent in orally disintegrating tablets

Abstract

Context: Considering that bitter taste of drugs incorporated in orally disintegrating tablets (ODTs) can be the main reason for avoiding drug therapy, it is of the utmost importance to achieve successful taste-masking. The evaluation of taste-masking effectiveness is still a major challenge.

Objective: The objective of this study was to mask bitter taste of the selected model drugs by drug particle coating with Eudragit^® E PO, as well as to evaluate taste-masking effectiveness of prepared ODTs using compendial dissolution testing, dissolution in the small-volume shake-flask assembly and trained human taste panel.

Materials and methods: Model drugs were coated in fluidized bed. Disintequik? ODT was used as a novel co-processed excipient for ODT preparation. Selected formulations were investigated in vitro and in vivo using techniques for taste-masking assessment.

Results and discussion: Significantly slower drug dissolution was observed from tablets with coated drug particles during the first 3?min of investigation. Results of in vivo taste-masking assessment demonstrated significant improvement in drug bitterness suppression in formulations with coated drug. Strong correlation between the results of drug dissolution in the small-volume shake-flask assembly and in vivo evaluation data was established (R?≥?0.970).

Conclusion: Drug particle coating with Eudragit^® E PO can be a suitable approach for bitter taste-masking. Strong correlation between in vivo and in vitro results implicate that small-volume dissolution method may be used as surrogate for human panel taste-masking assessment, in the case of physical taste-masking approach application.     

A model for the pyrolysis of two Nordic structural timbers

Performance-based design of the timber structures' fire resistance is often based on the reduced cross section and thus relying on empirical and numerical assessment of the charring propagation. The current work aims to construct models for the pyrolysis of spruce and pinewoods to allow coupled simulations of the cross-section reduction and burning rate in fire models. Kinetic models are formulated based on thermogravimetric data and supported by the heats of pyrolysis and combustion measurements by differential scanning calorimetry and microscale combustion calorimetry, respectively. The results from these small-scale measurements are consistent with each other, and the heats of pyrolysis and combustion are determined for the wood primary components by fitting the simulations to the experimental results. Heat release models are constructed based on the small-scale tests, and cone calorimeter experiments are used for the estimation of the physical properties and for the heat release model validation.     

Analysis of Fatigue and Crack Growth in Carbon-Fiber Epoxy Matrix Composite Laminates

A study of high frequency fatigue in carbon-fiber reinforced composites has been undertaken. A comparison has been made between the fatigue behavior of crossply (0° / 90°) and angleply (± 45°) carbon/epoxy unnotched and notched laminates. Additionally, a micromechanical analysis of fracture surfaces performed by scanning electron microscopy was carried out to evaluate the micromechanisms that occurred during fatigue. Experimental observations indicate that fatigue damage consists of a combination of matrix cracks, longitudinal splitting, fiber fracture, and delamination. In order to minimize the effects of residual strain due to temperature rise, a method is proposed for determining real fatigue strength at the level of variable load not lower than the fatigue limit, at which residual strains are minimal.     

Citalopram in the treatment of obsessive-compulsive disorder: an open pilot study

PURPOSE: To evaluate QT dispersion in hypertensive patients, with and without left ventricular hypertrophy, and compare with normal persons. METHODS: Thirty eight patients (21 male and 17 female, age 55 +/- 15 years) underwent echocardiography and simultaneous 12 lead, vertically aligned, electrocardiogram at 50 mm/s speed. No patient was on antiarrhythmic therapy. There were 19 non-hypertensive patients that constituted the control group (G-I). Group II was constituted by the other 19 patients, who were hypertensives. This group was further divided in group II-A (9 patients without left ventricular hypertrophy) and group II-B (10 patients with left ventricular hypertrophy). QT dispersion was obtained by the difference between the longest and the shortest QT registered. RESULTS: QT dispersion was significantly increased on hypertensive patients, both with and without left ventricular hypertrophy, when compared to controls (G-I 31 +/- 9 ms, G-II 52 +/- 15 ms. P < 0.0001; G-IIa 46 +/- 10 ms and G-IIb 56 +/- 18 ms X G-I, p < 0.0005). In hypertensive patients, there was no statistically significant difference between group II-A and group II-B. CONCLUSION: We conclude that QT dispersion is significantly increased on hypertensive patients when compared to non-hypertensive individuals and that such increase, occurs before left ventricular hypertrophy develops. These findings suggest that, in hypertensive patients, electrical changes in left ventricular myocardium can precede structural and morphological abnormalities. Such findings offer new insights into the mechanisms related to enhanced mortality among hypertensive patients.     

Hydroxyapatite coating of cellulose sponges attracts bone-marrow-derived stem cells in rat subcutaneous tissue

The presence of bone-marrow-derived stem cells was investigated in a wound-healing model where subcutaneously implanted cellulose sponges were used to induce granulation tissue formation. When cellulose was coated with hydroxyapatite (HA), the sponges attracted circulating haemopoietic and mesenchymal progenitor cells more efficiently than uncoated cellulose. We hypothesized that the giant cells/macrophages of HA-coated sponges recognize HA as foreign material, phagocyte or hydrolyse it and release calcium ions, which are recognized by the calcium-sensing receptors (CaRs) expressed on many cells including haemopoietic progenitors. Our results showed, indeed, that the HA-coated sponges contained more CaR-positive cells than untreated sponges. The stem cells are, most probably, responsible for the richly vascularized granulation tissue formed in HA-coated sponges. This cell-guiding property of HA-coated cellulose might be useful in clinical situations involving impaired wound repair.     

Performance evaluation of the phosphorescent porphyrin label: solid-phase immunoassay of alpha-fetoprotein

Phosphorescent conjugates of antibodies, neutravidin, and biotin (pentylamine derivative) were synthesized using previously described monofunctional labeling reagent of platinum(II) coproporphyrin-I with isothiocyanate reactive group (PtCP-NCS). These conjugates, which can be considered as standard reagents for a range of bioanalytical applications, were evaluated in solid-phase immunoassay schemes with the clinical analyte a-fetoprotein (AFP). A custom-designed time-resolved phosphorescence plate reader based on a compact and low-cost 532-nm laser and optimized for measurement of porphyrin labels was used. Using optimized tracers, instrumentation and assay protocols, subpicomolar detection limits were obtained both for PtCP label in solution and for AFP in solid-phase immunoassay. This sensitivity is comparable with standard time-resolved fluorescence immunoassays with lanthanide labels. The performance of metalloporphyrin labels, instrumentation, and solid-phase immunoassays as an alternative to the established detection platforms is discussed.