An immunohistochemical study of the role of matrix metalloproteinases and their tissue inhibitors in chronic mitral valvular disease (valvular endocardiosis) in dogs

While the pathogenesis of chronic valvular disease (CVD) in dogs remains unclear, alterations in the activity of specific metalloproteinase enzymes and their inhibitors within the valve stroma are suspected of having a role. This study describes the immunohistochemical distribution pattern of matrix metalloproteinase (MMP) types 2, 9 and 14 and their tissue inhibitors, termed tissue inhibitors of metalloproteinase (TIMP), types 2 and 3, in normal canine mitral valves (MVs) (n=10) and in dogs with mild (n=7), moderate (n=14) and severe (n=9) CVD. In normal MVs, MMP-2 and -14, and TIMP-2 were expressed in isolated stromal cells. Tissue inhibitor of metalloproteinase-3 exhibited moderate intracellular and mild extracellular expression. With increasing severity of CVD, the expression of MMP-2 decreased. The number of stromal cells expressing MMP-14 increased, predominantly in the margins of the nodular lesions. Tissue inhibitor of metalloproteinase-2 and -3 expression increased both intra- and extracellularly. Matrix metalloproteinase-9 was not detected in normal or diseased valves. In conclusion, CVD was characterised by alterations in the distribution and intensity of valvular MMP and TIMP expression, suggesting that depressed catabolism and the accumulation of extracellular matrix components within affected valves contributes to their structural alteration and consequent loss of function.     

Improvement of thermo-mechanical properties of basalt fiber using heat resistant polymeric coatings

Heat resistant coatings of textile materials are required so that they can fulfill the high security demand in the case of resistance to fire and improve thermo-mechanical properties. These coatings also enhance the interface properties of textiles in the composites. Liquid phase coatings, based on polysilazane and polysiloxane polymers were deposited onto the basalt fiber (BF) yarn using impregnation coating method. Tensile testing under thermal stress was conducted to examine the thermo-mechanical properties of both coated and uncoated yarns. The thermo-mechanical study indicated that the heat resistant coatings enhanced 40–70 % tensile strength and 25–40 % stiffness of original BF yarns up to 400 °C. BF yarn retained 65–90 % of its tensile strength at 500 °C due to coatings, whereas the uncoated BF yarn lost 85 % strength at this temperature. Thermo gravimetric analysis (TGA) showed that the coatings have good thermal stability. In addition, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, optical microscopy and fourier transform infrared (FTIR) spectroscopy analyses were executed in order to evaluate the surface microstructure as well as surface chemical compositions of the BF yarns.     

Wet-chemical silvering of inert polyethylene terephthalate yarn in a spool dyeing apparatus

Inert polyethylene terephthalate (PET) yarns, which were spooled crosswise onto a cylindrical dyeing bobbin, were silvered successfully with a wet-chemical method by using a newly developed one-bath method on a laboratory scale. In order to characterize the silver coating such as design, homogeneity, and crack formation, the surface morphology (SM) was analyzed using scanning electron microscopy (SEM). The chemical compositions of the surface (percentage of carbon, oxygen, nitrogen, silicium, and silver) were investigated with energy-dispersive x-ray spectroscopy (EDX). Furthermore, the testing of textile-chemical and textile-physical properties such as the washing-fastness, tensile strength, and electrical conductivity was carried out.     

Auswirkungen des Agroforestry-Anbausystems auf den Mineralstickstoffgehalt und das Matrixpotential in einer Parabraunerde sowie das Wachstum von Acer Pseudoplatanus

Effects of the agroforestry land use system on mineral nitrogen content and water potential in a Haplic Luvisol and on growth of Acer pseudoplatanus Results from three years are presented for an agroforestry system with Acer pseudoplatanus without (bare soil, treated with herbicides) and with undercropping, which was either Lolium perenne or Trifolium repens. The soil, a Haplic Luvisol derived from loess, had been intensively cultivated by agricultural crops before. Without undercropping leaching of nitrate was observed especially in the first, but also in the following years of the experimental period. This is due to the low and late N-demand of trees. Remaining contents of mineral nitrogen in the soil were sufficient for an optimal tree growth. With Lolium perenne as undercrop the mineral nitrogen content in the soil decreased in 0–60 cm depth as a result of N-uptake already in the first year. Leaching was observed from 60–90 cm depth. In the following years mineral nitrogen contents of the soil remained low, and were not sufficient for an optimal tree growth. Tree growth was further affected because of competition for water between gras and trees. With Trifolium repens mineral nitrogen in the soil was much higher than the demand for trees and undercrop due to symbiontic N-fixation by clover with subsequent mineralization. Although low water potentials were recorded similar to gras, competition for water did not diminish tree growth. Hence, optimal tree growth is guaranteed, but leaching of nitrate cannot be avoided. For all treatments leaching of N occured also in early spring. Up to now, there was no difference of tree growth between bare soil and Trifolium repens as undercrop, tree growth was much affected by Lolium perenne as undercrop.     

Soil organic matter composition and soil lightness

Relationships between soil lightness, soil organic matter (SOM) composition, content of organic C, CaCO₃, and texture were studied using 42 top‐soil horizons from different soil types located in southern Germany. SOM composition was determined by CPMAS ¹³C NMR spectroscopy, soil color was measured by diffuse‐reflectance spectrophotometry and given in the CIE L*a*b* color coordination system (Commission Internationale de l'Eclairage, 1978). Multiple‐regression analysis showed, that soil lightness of top‐soil horizons is principally determined by OC concentration, but CaCO₃ and soil texture are also major variables. Soil lightness decreased with increasing OC content. Carbonate content had an important effect on soil lightness even at low concentrations due to its lightening property. Regressions between soil lightness and organic C content were strongly linear, when the soils were differentiated according to texture and CaCO₃ content. The aryl‐C content was the only SOM component which correlated significantly with soil lightness (r_S = –0.87). In the linear regressions carried out on the different soil groups, soil aryl‐C content was a more significant predictor for soil lightness than total OC content.     

Der Einfluß künstlicher vertikaler Grobporen in einer verdichteten Bodenmatrix auf das Wachstum von Winterweizen I. Wachstum von Winterweizen auf einer Parabraunerde aus Löß

The influence of artificial vertical macropores in a compacted soil on the growth of winterwheat. I. Growth of winterwheat on an alfisol derived from loess In field experiments on a compacted alfisol it was investigated, how artificially made vertical macropores in the compacted structure influence water extraction and growth of winterwheat compared to the compacted structure without vertical macropores and to the loosened structure. The experiments were carried out in two subsequent years with different precipitation (308, 0 and 440, 1 mm in the period of November until August of both growth periods). The influence of the different soil structure was most pronounced during periods of increasing water tension. Compared to the compacted structure, water extraction as well as yield was improved by the vertical artificial macropores to a similar extend as by the loosened structure. Both structures increased water extraction from deeper parts of the soil (25-50 cm). The beneficial effects of the vertical macropores were more pronounced in the dry compared to the wet year. Despite of the unequal distribution of roots in the compacted structure with vertical macropores, water extraction from the soil between the macropores was not negatively affected.     

The prevalence of antimicrobial susceptibility of veterinary pathogens isolated from cattle and pigs: national antibiotic resistance monitoring 2002/2003 of the BVL

The national antimicrobial resistance monitoring determines the current quantitative resistance level of life-stock pathogens, in order to permit the evaluation and surveillance of the distribution of resistances on a valid basis. During the examination period from June 2002 to July 2003, a total of 1849 pathogens was collected, following a representative German-wide pattern in collaboration with 29 laboratories. The selection of examined bacterial strains included different specimen causing respiratory diseases in fattening pigs (Pasteurella multocida, Bordetella bronchiseptica) and cattle (Pasteurella multocida, Mannheimia haemolytica), respectively, as well as strains causing mastitis in dairy cows (Staphylococcus spp., Streptococcus spp., E. coli). Determination of the in-vitro susceptibility (minimal inhibitory concentration) to at least 17 antimicrobial agents was performed centrally by the BVL using the microdilution broth method. The findings approximately match results of an analogous study conducted in 2001, and correspondingly revealed significantly lower resistance-values in comparison to data published for Germany so far. No correlation could be established between the incidence of resistance and differing stock densities. By means of the resistance monitoring data gathered by the BVL, the risk potential of antimicrobials applied in Germany can be reliably defined. This valuable information about the epidemiological situation of resistance in Germany can be helpful to veterinarians as a decision guidance when choosing appropriate means of therapy. Accordingly, the results stated by the BVL are apt to provide an important contribution to improving the safety of food-animal products. The experiences obtained from the monitoring also show that valid data about the antimicrobial susceptibility can only be raised on an interdisciplinary approach (federal agencies, county diagnostic laboratories, universities, industry). Currently, the BVL put into practice a study with an extended spectrum of bacterial species and indications.     

The past and future of modeling forest dynamics: from growth and yield curves to forest landscape models

Context

Quantitative models of forest dynamics have followed a progression toward methods with increased detail, complexity, and spatial extent.

Objectives

We highlight milestones in the development of forest dynamics models and identify future research and application opportunities.

Methods

We reviewed milestones in the evolution of forest dynamics models from the 1930s to the present with emphasis on forest growth and yield models and forest landscape models We combined past trends with emerging issues to identify future needs.

Results

Historically, capacity to model forest dynamics at tree, stand, and landscape scales was constrained by available data for model calibration and validation; computing capacity; model applicability to real-world problems; and ability to integrate biological, social, and economic drivers of change. As computing and data resources improved, a new class of spatially explicit forest landscape models emerged.

Conclusions

We are at a point of great opportunity in development and application of forest dynamics models. Past limitations in computing capacity and in data suitable for model calibration or evaluation are becoming less restrictive. Forest landscape models, in particular, are ready to transition to a central role supporting forest management, planning, and policy decisions.

Recommendations

Transitioning forest landscape models to a central role in applied decision making will require greater attention to evaluating performance; building application support staffs; expanding the included drivers of change, and incorporating metrics for social and economic inputs and outputs.