Wood–plastic composites (WPCs) have received increasing attention during the last decades, because of many advantages related to their use. Some of their main applications are represented by outdoor ...furnishing and decking; therefore, it is important to assess their behaviour under UV exposure. In this work, polypropylene/wood flour composites were prepared and their resistance to photooxidation investigated. The composites were prepared by extrusion and compression moulding, and were subjected to mechanical tests, FTIR analysis and molecular weight measurements. The results showed that the composites retained a higher fraction of the original mechanical properties after accelerated weathering; the wood flour did not significantly degrade throughout the irradiation time slot of the investigation and the composites kept a higher percentage of the original molecular weight.
Serum interleukin 10 (IL10) levels were assessed in patients with multiple sclerosis who were either in a stable or active clinical condition. The levels were compared with values in healthy ...controls. Lower IL10 levels than in controls were seen in multiple sclerosis patients, regardless of clinical disease activity. Low IL10 levels were also seen in patients with systemic lupus erythematosus. No clear-cut relationships emerged between IL10 levels and those of tumour necrosis factor alpha and transforming growth factor beta, or between IL10 and lymphocyte subsets in peripheral blood.
This work investigated the effects of land cover and land-use change (LUC) on the ability of a soil to store carbon (C) and reduce carbon dioxide (CO
2) emissions, in a Mediterranean area. Using a ...paired-site approach, we estimated the effect of land-cover change on the C stock from 1972 to 2008 in a natural reserve (Grotta di Santa Ninfa) in western Sicily. We selected 15 paired sites representative of five LUCs. We studied the effect of land use on soil organic C (SOC) content in bulk soil and in different particle-size fractions (2000–1000
μm, 1000–500
μm, 500–250
μm, 250–63
μm, 63–25
μm, and <
25
μm). Laboratory incubation of the soil samples was conducted to measure CO
2 evolution in bulk soil collected at two different depths from each paired site. We found that the conversion of natural vegetation to orchards (vineyards and olive groves) resulted in SOC decreases ranging from 27% to 50%. The conversion from vineyards to arable land led to a 9% decrease in SOC, whereas the opposite caused a 105% gain. When arable land was replaced by
Eucalyptus afforestation, a 40% increase in SOC was observed. SOC decline occurred mainly in coarser soil fractions, whereas the finest fractions were not influenced by land use. We calculated an overall SOC reduction of 63% in the study area, corresponding to a 58
Mg
ha
−
1
SOC loss in less than 30
years. Our results indicate that land-use conversion, vegetation type, and management practices that control the biogeochemical and physical properties of soil could help reduce CO
2 emissions and sequester SOC.
► The SOC content is strongly affected by land cover and land use change. ► SOC losses are mainly associated with coarser fractions. ► OC content in bulk soil shows a significant negative linear relationship with CO
2 flux.
Environmental and genetic factors seem to play a pathogenetic role in multiple sclerosis (MS). The genetic component is partly suggested by familial aggregation of cases; however, MS families with ...affected subjects over different generations have rarely been described. The aim of this study was to report clinical and genetic features of a multigenerational MS family and to perform a review of the literature on this topic. We describe a multigenerational Italian family with six individuals affected by MS, showing different clinical and neuroradiological findings. HLA-DRB1* typing revealed the presence of the DRB1*15:01 allele in all the MS cases and in 4/5 non-affected subjects. Reports on six multigenerational MS families have previously been published, giving similar results. The HLA-DRB1*15:01 allele was confirmed to be linked to MS disease in this family; moreover, its presence in non-affected subjects suggests the involvement of other susceptibility factors in the development and expression of the disease, in accordance with the complex disease model now attributed to MS.
The concept of vascular compression of the trigeminal root as the main etiological factor in idiopathic trigeminal neuralgia has achieved widespread acceptance, and microvascular decompression (MVD) ...is a well-established surgical procedure for its treatment. Multiple sclerosis (MS) has long been considered to be an absolute contraindication to MVD because of the supposed exclusive causative role of a demyelinating lesion affecting the trigeminal root entry zone. Magnetic resonance imaging preoperative identification of suspicious vessels along the cisternal course of the trigeminal nerve in MS patients raises the question of a possible causative role of vascular compression in MS patients.
We describe magnetic resonance imaging findings, surgical findings, and outcomes in 35 MS patients who underwent MVD for medically intractable trigeminal neuralgia. Results were assessed by clinical follow-up and periodic phone surveys. The mean follow-up was 44 months (range, 6-108 mo).
Magnetic resonance imaging revealed the presence of demyelinating lesions affecting the brainstem trigeminal pathways of the painful side in 26 (74%) of 35 patients. During surgery, severe neurovascular compression at the trigeminal root entry zone was found in 16 (46%) of 35 patients. The long-term outcome was excellent in 39%, good in 14%, fair in 8%, and poor in 39% of patients. No statistically significant prognostic factor predicting good outcome could be found. There was no mortality, with a 2.5% long-term morbidity rate (facial nerve palsy in one patient).
Results of MVD in trigeminal neuralgia MS patients are much less satisfactory than in the idiopathic group, indicating that central mechanisms play a major role in pain genesis.
Several compatibilising systems were added to high-density polyethylene (HDPE) and polyamide 6 (PA6) blends in the presence of an organically modified montmorillonite (OMM). All the blends were ...prepared by using a co-rotating twin-screw extruder and characterized by SEM, TEM and XRD analyses. In addition, the rheological behaviour and the mechanical properties – tensile and impact – were evaluated.
The presence of OMM affects the dimensions of the polymeric phases in the blend but not their mutual adhesion, granted only by the compatibilisers.
TEM, SEM and XRD analyses indicated that there is a strict correlation between the compatibilisation level and the final interlayer distance achieved by OMM.
Even if some filled compatibilised blends showed a fairly good morphology – in terms of phase adhesion, dispersion and dimension – the mechanical performance was not so satisfactory. These results were interpreted considering the possible thermo-oxidative degradation of the organic modifier of OMM and the subsequent interaction between and the degradation products and the compatibilising systems. In order to prevent these phenomena, a stabilizing system was added to the nanocomposite blends. In this case, an improvement of mechanical properties was achieved.
The impact of small amounts of organomodified clay (OMMT) on the photo-degradation behaviour of two blends obtained by mixing either low-density polyethylene (LDPE) or high density polyethylene ...(HDPE) with polyamide 6 (PA6) (LDPE/PA6 and HDPE/PA6 75/25 wt-%) was studied. The complex photo-degradation behaviour was followed by monitoring the main physical–mechanical properties of the blends. In particular, mechanical and spectroscopic tests were performed in conditions of accelerated artificial aging. An accurate mechanical and morphological characterization was previously carried out. The presence of the OMMT promotes the unexpected formation of a co-continuous morphology for the HDPE/PA6 blend without significantly improving the interfacial adhesion. Differently, the OMMT-filled LDPE/PA6 blend exhibits a finely distributed morphology, and some apparent improvement of the interfacial adhesion was noticed. Probably due to these differences in microstructure, a different impact of the nanoparticles on the photo-resistance behaviours was observed for the two families of samples. In particular, the HDPE-based nanocomposite blend exhibits an improved photo-resistance, while the opposite occurs for the LDPE-based system.
The aim of this work was to determine some relevant rheological parameters of polymer/clay systems using mixing torque and mixing speed data obtained during processing in an internal mixer. The ...method used was originally proposed by Marquez et al. for monophase polymers, and is here applied to polymer/clay systems for the first time. Several clay-containing composites based on different polymer matrices (i.e., LDPE, HDPE, PA6, EVA) were used to verify the effectiveness of the method for measuring the flow curves of these polymer/clay systems. The results indicated that, for all the systems at low clay level, the rheological curves calculated with the Marquez method fit quite well those measured in both rotational and capillary rheometers. On the contrary, on increasing the amount of clay, the flow curves estimated by the melt mixing torque data still fit those measured by rotational rheometer while diverging from those measured by the capillary viscometer. Indeed, the polymer-clay systems do not obey the Cox-Merx rule at high filler content.
In this paper the photo-oxidation behaviour of polyolefin/clay nanocomposite films was studied; in particular, the effect of the amount of organo-modifier and the matrix polarity on the ...photo-oxidation was investigated. Two different organo-modified clays and compositions of LDPE/EVA blend films were used and the photo-oxidation was followed by mechanical and spectroscopic analyses.
The organoclay and matrix type strongly influence the photo-oxidative behaviour of nanocomposite films. The films filled with CL15A show a faster loss of mechanical performance and higher carbonyl formation with respect to the films filled with the CL20A. Additionally, the LDPE based nanocomposite undergoes photo-oxidation more rapidly than the EVA based one.
Blends of polyamide 6 (PA6) and high-density polyethylene (HDPE) were compatibilized using an already investigated method and a sample of Cloisite 15A, a montmorillonite modified with ammonium ...quaternary salts was added. The blends were prepared in a twin screw extruder and characterized from a morphological, rheological and mechanical point of view. The results indicated that, despite a good morphology achieved in the filled blends and a moderate intercalation of the clay, the mechanical properties are far from being good, especially the ultimate properties.
In order to investigate the possible influence of the inhibition of the crystallization and of the degradation of the organic modifier of the clay, DSC measurements and FTIR–ATR were carried out. The results confirm that the clay causes a slight decrease of the crystallization, particularly in the HDPE phase. In addition, in the preparation conditions, the clay modifier is sensitive to thermo-oxidation. Both features can, therefore, explain the bad mechanical performance, even if the degradation effects seem to be more important. In order to prevent, or at least to reduce, the thermo-oxidation, a stabilizing system was added to the filled blends. In this case, the mechanical properties are improved for the entire compatibilized blend set.
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