Modification of wood with silicon compounds. Treatment systems based on organic silicon compounds — a review

A wide variety of organo-silicon compounds has been described for application on wood. Some compounds such as organo-functional silanes which are mostly applied in combination with tetraalkoxysilanes (sol-gel process) as well as chlorosilanes and trimethylsilyl derivatives were proposed for a full impregnation treatment of wood. Other systems have been developed for surface treatment of wood such as plasma coating with hexametyldisiloxane and micro-emulsions which mainly contain silane/siloxane mixtures. The effects related to the various treatments vary from an increase in dimensional stability, durability and fire resistance to an enhanced hydrophobation of wood. In the cases of decay and fire resistance a combination of silicon based systems with other chemicals was required to obtain satisfactory results. Due to the excellent water repellent ability and weathering stability of some treatments, application of silicon treated wood under conditions of hazard class III (EN 335 outside above ground exposure) is recommended.Abbreviations ASE anti-shrink efficiency - ATR-FT-IR attenuated total reflectance — Fourier transform infrared spectroscopy - CP MAS-NMR cross polarisation magic angle spinning nuclear magnetic resonance spectroscopy - DTA differential thermal analysis - DTMOS decyltrimethoxysilane - EDX energy dispersive x-ray analysis - EETMOS -(3,4 epoxycyclohexyl) ethyl trimethoxysilane - EMC equilibrium moisture content - ESCA electron spectroscopy for chemical analysis - HFOETMOS 2-heptadecafluorooctylethyltrimethoxysilane - HMDSO hexamethyldisiloxane - IPTEOS 3-isocyanatepropyl triethoxysilane - MPTMOS -methacryloxypropyl trimethoxysilane - MTMOS methyltrimethoxysilane - PDMS polydimethylsiloxane - PTMOS propyltrimethoxysilane - TEOS tetraethoxysilane / triethyl orthosilicate - TFPTMOS 3,3,3-trifluoropropyltrimethoxysilane - TGA thermo-gravimetric analysis - TMSAH 3-(trimethoxysilyl)propyl (carboxymethyl) decylmethyl ammonium hydroxide inner salt - TMSCl trimethylsilyl chloride - TPT tetraisopropyl titanate - VTMOS vinyl trimethoxysilane - WPG weight percent gain - WRE water repellent efficiency     

In vitro comparison of tibial plateau leveling osteotomy with and without use of a tibial plateau leveling jig

OBJECTIVE: To evaluate the influence of a tibial plateau leveling jig on osteotomy orientation, fragment reduction, and postoperative tibial plateau angle (TPA) during tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: In vitro experimental study. ANIMALS: Large-breed canine cadavers (n=20). METHODS: TPLO was performed on 40 hindlimbs using 4 methods. Group 1: Jig; dogs in dorsal recumbency with the osteotomy parallel to the distal jig pin. Groups 2-4: No jig; dogs in lateral recumbency with the osteotomy in a vertical orientation (group 2: tibia parallel to the table top; group 3: controlled superimposition of the femoral condyles; group 4: internal rotation of the tibia). Postoperative TPA, fragment reduction, and osteotomy orientation relative to the tibial plateau were compared. Positive or negative values denoted deviation from parallel relative to the tibial plateau. RESULTS: Postoperative TPA, fragment reduction, and proximodistal osteotomy orientation were not significantly different between groups. Craniocaudal osteotomy orientation was significantly different (P<.005) from the tibial plateau. Median deviations were -4.0 degrees (group 1), 11.8 degrees (group 2), 11.2 degrees (group 3), and 0.2 degrees (group 4). Group 1 was not significantly different from group 4. CONCLUSIONS: A jig is not essential for osteotomy orientation, tibial plateau rotation, or fragment reduction. Comparable results were achieved performing a vertical osteotomy with the tibia slightly internally rotated (10 degrees -15 degrees) and parallel to the table surface. CLINICAL RELEVANCE: TPLO without use of a jig reduces surgical trauma, is less time consuming, and reduces cost.     

Temporal development and collapse of an Arctic plant-pollinator network

Background  

The temporal dynamics and formation of plant-pollinator networks are difficult to study as it requires detailed observations of how the networks change over time. Understanding the temporal dynamics might provide insight into sustainability and robustness of the networks and how they react to environmental changes, such as global warming. Here we study an Arctic plant-pollinator network in two consecutive years using a simple mathematical model and describe the temporal dynamics (daily assembly and disassembly of links) by random mechanisms.     

Evaluating the most suitable nonlinear growth model for turbot (Scophthalmus maximus) in aquaculture 2 (weight application): Multi‐criteria model selection and growth prediction

Seeking the most suitable model to describe the growth of turbot, we analysed growth data of two different turbot (Scophthalmus maximus) strains reared communally in a recirculating aquaculture system. We fitted 10 different nonlinear growth models to individual weight gain data (n = 2,010) during the grow‐out phase. Analyses were carried out for each strain, for sexes within strains and for a pooled data set containing both strains and sexes. To assess the model performance, three different criteria are used. Further, a growth‐simulation was performed to evaluate the shape of the generated curve. This way we could assess the capability of the models to predict future growth. The 3‐parametric Gompertz model achieved the best fit in 42.9% of all cases tested and the lowest Bayesian information criterion in 100% of cases. The model produced realistically shaped curves and asymptotic values matching the biological attributes of the species. In contrast, 5‐parametric functions projected unrealistically shaped curves and predicted improbable mature sizes. Our results show that increasing number of parameters do not lead to increasing goodness of fit, but tend to result in overfitting, and demonstrate the advantages of the 3‐parametric Gompertz model for describing the growth of turbot.     

(Q)SAR tools for the prediction of mutagenic properties: Are they ready for application in pesticide regulation?

The assessment of human health risks resulting from the presence of metabolites in groundwater and food residues has become an important element in pesticide authorisation. In this context, the evaluation of mutagenicity is of particular interest and a paradigm shift from exposure‐triggered testing to in silico‐based screening has been recommended in the European Food Safety Authority (EFSA) Guidance on the establishment of the residue definition for dietary risk assessment. In addition, it is proposed to apply in silico predictions when experimental mutagenicity testing is not possible due to a lack of sufficient quantities of the pesticide metabolite. This, combined with animal welfare and economic considerations, has led to a situation where an increasing number of in silico studies are submitted to regulatory authorities. Whilst there is extensive experience with in silico predictions for mutagenicity in the chemical and pharmaceutical industry, their suitability in pesticide regulation is still insufficiently considered. Therefore, we herein discuss critical issues that need to be resolved to successfully implement (Quantitative) Structure‐Activity Relationship ((Q)SAR) as an accepted tool in pesticide regulation. For illustration purposes, the results of a pilot study are included. The presented study highlights a need for further improvement regarding the predictivity and applicability domain of (Q)SAR systems for pesticides and their metabolites, but also raises other questions such as model selection, establishment of acceptance criteria, harmonised approaches to the combination of model outputs into overall conclusions, adequate reporting and data sharing. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Cropland change in southern Romania: a comparison of logistic regressions and artificial neural networks

Changes in cropland have been the dominating land use changes in Central and Eastern Europe, with cropland abandonment frequently exceeding cropland expansion. However, surprisingly little is known about the rates, spatial patterns, and determinants of cropland change in Eastern Europe. We study cropland changes between 1995 and 2005 in Argeş County in Southern Romania with two distinct modeling techniques. We apply and compare spatially explicit logistic regressions with artificial neural networks (ANN) using an integrated socioeconomic and environmental dataset. The logistic regressions allow identifying the determinants of cropland changes, but cannot deal with non-linear and complex functional relationships nor with collinearity between variables. ANNs relax some of these rigorous assumptions inherent in conventional statistical modeling, but likewise have drawbacks such as the unknown contribution of the parameters to the outcome of interest. We compare the outcomes of both modeling techniques quantitatively using several goodness-of-fit statistics. The resulting spatial predictions serve to delineate hotspots of change that indicate areas that are under more eminent threat of future abandonment. The two modeling techniques address two controversial issues of concern for land-change scientists: (1) to identify the spatial determinants that conditioned the observed changes and (2) to deal with complex functional relationships between influencing variables and land use processes. The spatially explicit insights into patterns of cropland change and in particular into hotspots of change derived from multiple methods provide useful information for decision-makers.     

Establishment of Tabulated Values for Standardized Ileal Digestibility of Crude Protein and Essential Amino Acids in Common Feedstuffs for Pigs

Literature data on apparent ileal digestibility of crude protein (CP) and amino acids in pigs from 79 references (203 observations) including 13 different common feedstuffs, and other data on basal endogenous ileal loss of CP and amino acids from 32 references (36 observations) were analysed statistically. The analyses revealed that the cannulation method as well as the method for determining endogenous ileal losses of CP and amino acids affected the results. After correction for these effects a new set of tabulated values for apparent and standardized ileal digestibility of crude protein and essential amino acids was generated. The results were in most cases in good agreement with three recently published tables for standardized ileal digestibility of amino acids in feedstuffs. Therefore, it was concluded that the data obtained in the present work, together with those given in the recently published tables, would be a suitable basis for a general table for standardized ileal digestibility of CP and amino acids in common feedstuffs for pigs.     

Regionalization of Magnetic Susceptibility Measurements Based on a Multiple Regression Approach

The article presents results of a case study in northeastern Germany, where magnetic susceptibility assessment was carried out at grid-wise field measurements. The measurements were clustered into three different depth levels, which represent the humus layer, the transition zone between humus layer and mineral horizon, and the mineral horizon. Taking these three depth levels, a multiple regression-based regionalization approach was applied, testing and using additional environmental parameters derived from geology, topography, and stand type with the aim to develop a comprehensive model for spatial variability of magnetic susceptibility. Spatial variation of magnetic susceptibility was predicted with a high precision by the multiple linear regression models. A slightly differing set of model parameters was selected for the single depth levels. In tendency, magnetic susceptibility values in depth level 6–10 cm were best explained by the distance to Bitterfeld and by soil properties. In depth level 11–15 cm, variables which describe the orographic conditions and stand properties gain in importance. In depth level 21–25 cm, variables indicating soil and site properties disappear completely. Here, aspect and land surface characteristics play a major role together with stand properties. A spatial stratification of the model for a distance of up to 25 km to the former emitters provided a further improvement of the model quality considering the prediction of small-scale variations of magnetic susceptibility.     

Analysis of the prevalence of distichiasis in the dog breed Elo

The Elo is a recently established dog breed in which the eye anomaly distichiasis has been frequently observed. Out of a total of 234 Elo dogs ophthalmologically examined over four years, 27.8% of the dogs showed between 1 and 31 distichia. There were twice as many distichia in the upper than in the lower eyelid. Litter size, the number of examinations of Elo dogs per ophthalmologist and the proportion of genes of the Eurasian dog had a significant influence on the prevalence of distichiasis. The error probability for the inbreeding coefficient and the proportion of genes of the Old English Sheepdog were just above the significance limit of p = 0.05. No significance was found for the remaining effects. Heritability for distichiasis was estimated using a linear animal model. After transformation of the linear observed estimate onto the underlying liability scale the heritability estimate was h2 = 0.43.