Flat pressed wood plastic composites made of milled foam core particleboard residues

Flat pressed wood plastic composites were produced on a laboratory-scale using residues of lightweight foam core particleboards as raw material. Raw material preparation methods (dry blending and compounding with a twin screw extruder) and the wood flour content (WF) loading, as influencing parameters on the panel properties, were varied, and coupling agents (CA) were added in some variations. The results showed that panels produced with lower WF content (75 %) have better physical and mechanical properties compared to those of higher WF. The CAs only influenced the panel properties when they were added during the compounding of the materials. Due to the assumed higher wood degradation resulting from raw material compounding, the panel properties were inferior to the panels produced with dry blended materials.     

Modelling of airborne dust emissions in CNC MDF milling

All dust control measures are necessary to reduce dust exposure in MDF (Medium Density Fibreboard)-milling, because of the high amount and fineness of the dust produced and a potential risk of exposure to formaldehyde or other glue chemicals during the machining of MDF. The most effective way of reducing dust exposure is to reduce the emission of dust at the source. Airborne dust emission was studied and modelled in the milling. In the milling of MDF, airborne dust emission was much higher than in the milling of solid materials. Milling of MDF produced airborne particles with a mass median diameter of 6–7 µm. The most significant factor affecting the amount of dust created from milling was average chip thickness. In order to reduce the amount of dust, milling parameters should be chosen so that the average chip thickness is greater than 0.05 mm. The average chip thickness could be obtained with different milling parameters, for example with different combinations of feed and traverse rates. The same chip thicknesses resulted in around the same percentage fraction of fine dust mass regardless of how the average chip thickness was obtained. The relationship between the percentage fraction of fine dust mass from the removed mass (c_%) and the chip thickness (h_m) was modelled and presented in the form of c_% = 0.194 h _m ^-1. The model developed can be used to estimate the percentage fraction of fine dust mass as a function of chip thickness. The model can be used in optimisation programs for CNC milling machines to minimize the airborne dust generated and to reduce dust exposure.     

Determination of polycyclic aromatic hydrocarbons (PAH) in edible vegetable oils by liquid chromatography and programmed fluorescence detection. Comparison of caffeine complexation and XAD-2 chromatography sample clean-up

Two clean-up procedures were compared for the analysis for polycyclic aromatic hydrocarbons (PAHs) in edible vegetable oils. One method comprises a liquid-liquid extraction followed by XAD-2 chromatography and the other a caffeine-formic acid complexation. The clean-up step is followed by gradient reversed-phase HPLC in combination with wavelength-programmed fluorescence detection. Due to better repeatability and simplicity, the XAD-2 method was selected for the determination of PAHs in 14 different vegetable oils. Between the different oil samples large differences were observed in PAH concentrations. PAH concentrations in vegetable oils sampled from the Dutch market appear to be comparable with those found in other countries.     

The Effect of Ferula communis Extract in Escherichia coli Lipopolysaccharide-Induced Neuroinflammation in Cultured Neurons and Oligodendrocytes

In recent decades, interest in natural compounds has increased exponentially due to their numerous beneficial properties in the treatment of various acute and chronic diseases. A group of plant derivatives with great scientific interest is terpenic compounds. Among the plants richest in terpenes, the genus Ferula L. is one of the most representative, and ferutinin, the most common sesquiterpene, is extracted from the leaves, rhizome, and roots of this plant. As reported in the scientific literature, ferutinin possesses antioxidant and anti-inflammatory properties, as well as valuable estrogenic properties. Neurodegenerative and demyelinating diseases are devastating conditions for which a definite cure has not yet been established. The mechanisms involved in these diseases are still poorly understood, and oxidative stress is considered to be both a key modulator and a common denominator. In the proposed experimental system, co-cultured human neurons (SH-SY5Y) and human oligodendrocytes (MO3.13) were treated with the pro-inflammatory agent lipopolysaccharide at a concentration of 1 μg/mL for 24 h or pretreated with ferutinin (33 nM) for 24 h and subsequently exposed to lipopolysaccharide 1 μg/mL for 24 h. Further studies would, however, be needed to establish whether this natural compound can be used as a support strategy in pathologies characterized by progressive inflammation and oxidative stress phenomena.     

Hemangioma of the temporal bone in a patient presumed to have Ménière's syndrome

This case report describes a patient with a facial nerve hemangioma of 8 years' duration that initially caused most of the symptoms of Ménière's syndrome: fullness, sensorineural hearing loss, dizziness, tinnitus, and disruption of balance. The hearing loss was in the high-frequency range (> or = 3,000 Hz); typically, the initial hearing loss in Ménière's syndrome is in the low-frequency range. Mild facial nerve weakness and punctate keratitis due to corneal exposure appeared 8 years later. Contrast-enhanced magnetic resonance imaging and high-resolution computed tomography depicted the lesion and made preoperative diagnosis possible. With meticulous surgical removal of the tumor, which was intertwined with the facial nerve, facial nerve function was preserved.     

编码多载波CDMA在下行Rice衰落信道下的性能分析

文中讨论了一种新的CDMA体制,即将OFDM调制技术应用于CDMA的MC-CDMA。从理论上分析了编码MC-CDMA经过下行Rice衰落信道的性能,针对接收端采用分集与Viterbi译码相结合的接收技术,给出下行链路的误码率表达式,并模拟了性能曲线。