Long-term studies (1871-2000) on acidification and recovery of lakes in the Bohemian Forest (central Europe)

This paper evaluates long-term changes in the atmospheric depositions of S and N compounds, lake water quality, and biodiversity at eight glacial lakes in the Bohemian Forest over the past 130 years. This time interval covers (i) the 'background' pre-acidification status of the lakes, (ii) a period of changes in the communities that can be partly explained by introduction of fish, (iii) a period of strong lake acidification with its adverse impacts on the communities, (iv) the lake reversal from acidity, which includes the recent status of the lakes. The lake water chemistry has followed-with a characteristic hysteresis-both the sharp increase and decline in the deposition trends of strong anions. Remarkable changes in biota have mirrored the changing water quality. Fish became extinct and most species of zooplankton (Crustacea) and benthos (Ephemeroptera and Plecoptera) retreated due to the lake water acidification. Independent of ongoing chemical reversal, microorganisms remain dominant in the recent plankton biomass as well as in controlling the pelagic food webs. The first signs of the forthcoming biological recovery have already been evidenced in some lakes, such as the population of Ceriodaphnia quadrangula (Cladocera) returning into the pelagial of one lake or the increase in both phytoplankton biomass and rotifer numbers in another lake.     

Microchip sonic spray ionization

The first microchip version of sonic spray ionization (SSI) as an atmospheric pressure ionization source for mass spectrometry (MS) is presented. The microchip used for SSI has recently been developed in our laboratory, and it has been used before as an atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) source. Now the ionization is achieved simply by applying high (sonic) speed nebulizer gas, without heat, corona discharge, or high voltage. The microchip SSI was applied to the analysis of tetra-N-butylammonium, verapamil, testosterone, angiotensin I, and ibuprofen. The limits of detection were in the range of 15 nM to 4 microM. The technique was found to be highly dependent on the position of the chip toward the mass spectrometer inlet, and on the gas and the sample solution flow rates. The microchip SSI provided dynamic linearity following a pattern similar to that used with electrospray, good quantitative repeatability (RSD=16%), and long-term signal stability.     

Biodiesel from rapeseed oil,methanol and KOH. 3. Analysis of composition of actual reaction mixture

Detailed analysis is described of the samples taken after suitable reaction times from the actual reaction mixture during the production of biodiesel fuel using methanolysis of rapeseed oil catalyzed by KOH. Three methods for stoppage of reaction (neutralisation of catalyst, dilution by two suitable solvents) in the sample are used. The contents of mono‐, di‐ and triacylglycerols, methylesters of fatty acids (biodiesel) and potassium salts of fatty acids of rapeseed oil, glycerol (by HPLC method), basicity (by potentiometric titration) and water (by GC and Karl‐Fischer method) in the samples are determined. An example of these determinations is described.     

Gradient Composites of Alkaline Poly(6‐hexanelactam) with Graphite: One‐Step Synthesis,Structure, and Mechanical Properties

In a one‐step synthesis of gradient composites, molten monomer of 6‐hexanelactam was mixed with graphite (5 wt.‐%) and alkaline polymerization was performed under quasi‐isothermal conditions at about 170°C. The following initiator/activator system insensitive to traces of water and other low‐molecular‐weight compounds adsorbed on filler surface was used: the sodium salt was prepared through the reaction of sodium dicaprolactamobis(2‐methoxyethoxo)aluminate with 6‐hexanelactam; N‐acyllactam was formed in situ in molten monomer by solving flexible or rigid polyurethane foam consisting of either toluene diisocyanate or diphenylmethane‐4,4′‐diisocyanate, and a poly(propylene oxide) based polyol. To obtain gradient composites with a compositional variation between plane‐parallel surfaces, the incorporated filler underwent sedimentation due to gravity during initial stages of polymerization. The graphite‐free surface is suitable for treatment with adhesives, while the graphite‐rich surface layer (containing about 11 wt.‐% of graphite) possesses improved friction characteristics. Graphite slightly (i) reduces the polymer yield and the mean spherulite diameter; (ii) increases the crystallinity due to its nucleation activity; (iii) decreases the compliance, but does not affect its time dependence given by the matrix and (iv) reduces the yield strength, tensile strength and elongation at break. The friction coefficient of the graphite‐rich surface is reduced to almost 50% of that found for the graphite‐free surface; composites with cross‐linked matrix also show better wear properties.     

A parallel fixed-point predictive controller

A parallel fixed-point implementation of a general predictive controller is derived. It is based on the concepts of predictive control outlined by Chisci, Zappa and Mosca. These controllers use parallel identification arrays as the basic building blocks. In this paper the largest part of the standard information filter array is replaced with a similar array which uses normalized data suitable for fixed-point VLSI implementation. The normalization ensures that all the data are within the range [−1, 1]. The controller includes an effective regularization scheme which allows a priori information about the plant and the controller to be included and kept permanently present in the identification scheme. Users can select the level of the influence of this a priori information on the controller adaptation relative to the effect of the measured data. The resultant architecture is suitable for fixed-point VLSI or DSP application aiming for low power and minimal complexity or maximal speed. © 1997 John Wiley & Sons, Ltd.     

A Complex Evaluation of the In-Vivo Biocompatibility and Degradation of an Extruded ZnMgSr Absorbable Alloy Implanted into Rabbit Bones for 360 Days

The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure—the removal of the plates and screws—can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.     

IL-6 in the Ecosystem of Head and Neck Cancer: Possible Therapeutic Perspectives

Interleukin-6 (IL-6) is a highly potent cytokine involved in multiple biological processes. It was previously reported to play a distinct role in inflammation, autoimmune and psychiatric disorders, ageing and various types of cancer. Furthermore, it is understood that IL-6 and its signaling pathways are substantial players in orchestrating the cancer microenvironment. Thus, they appear to be potential targets in anti-tumor therapy. The aim of this article is to elucidate the role of IL-6 in the tumor ecosystem and to review the possible therapeutic approaches in head and neck cancer.     

Cultivar differences of total anthocyanins and anthocyanidins in red and purple-fleshed potatoes and their relation to antioxidant activity

Total anthocyanins (TAC) and individual anthocyanidins (AN) after hydrolysis were measured in 15 red and purple-fleshed potato cultivars produced in five different locations in the Czech Republic and a new cultivar Blaue St. Galler from Switzerland. It was found that TAC, expressed as cyanidin content, varied between 0.7 mg 100 g⁻¹ FW (cv. Blue Congo) and 74.3 mg 100 g⁻¹ FW (cv. Blaue Ludiano). Major differences in cultivars were found for AN relative abundance. For cv. Highland Burgundy Red a high proportion of pelargonidin (98.7%) was characteristic, whereas cv. British Columbia Blue contained almost exclusively cyanidin. Cultivars Violette and Vitelotte showed a relatively high content of malvidin. Cultivar Shetland Black differed from others with its higher content of peonidin (on average 36.7%). High petunidin abundance in the cultivars Valfi, Blue Congo, Salad Blue, Blaue St. Galler, Blaue Hindel Bank, Blaue Ludiano, Blaue Schweden, Farbe Kartoffel and Salad Red was found. TAC and AN contents highly corresponded with antioxidant activity (AA) determined with the ABTS, FRAP and DPPH assays in vitro. High AA was shown by the cultivars Vitelotte, Violette, Blaue Ludiano, Hafija, and Highland Burgundy Red. Increased height above sea level, higher annual sum of precipitation, and lower annual average temperatures caused higher AA and TAC. A high degree of hydroxylation and/or methoxylation of individual anthocyanidins could contribute in conjunction with other phenolics to high AA (peonidin, delphinidin and malvidin in the cultivars Blue Congo, Highland Burgundy Red and Shetland Black). Consequently, new red and purple-fleshed cultivars with high TAC and highly methoxylated and/or hydroxylated AN could be a promising source of favourable antioxidants in human nutrition.     

3,5-Dinitrosalicylic acid-assisted synthesis of self-assembled polyaniline nanorods

Self-assembled polyaniline nanorods were synthesized by the oxidation of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 3,5-dinitrosalicylic acid, using the template-free falling-pH method. The effects of the mole ratio of 3,5-dinitrosalicylic acid to aniline, i.e., of starting pH, monomer concentration, and reaction time on the yield of polymerization, molecular-weight distribution, molecular structure, morphology, and conductivity of the prepared polyanilines have been studied by gel-permeation chromatography, elemental analysis, FTIR and Raman spectroscopies, scanning and transmission electron microscopies, and conductivity measurements. The weight-average molecular weights and polydispersity index were in the range 36,400-54,900 and 3.7-7.6, respectively. Synthesized polyaniline nanorods have a diameter of 25-280 nm and a length of 0.2-1.3 μm, and conductivities in the range (1.2-4.6) × 10⁻² S cm⁻¹. The formation mechanism of self-assembled polyaniline nanorods has been discussed.     

Gender differences in implicit and explicit processing of emotional facial expressions as revealed by event-related theta synchronization.

Emotion information processing may occur in 2 modes that are differently represented in conscious awareness. Fast online processing involves coarse-grained analysis of salient features and is not represented in conscious awareness; offline processing takes hundreds of milliseconds to generate fine-grained analysis and is represented in conscious awareness. These processing modes may be studied using event-related electroencephalogram theta synchronization as a marker of emotion processing. Two experiments were conducted that differed on the mode of emotional information presentation. In the explicit mode, subjects were explicitly instructed to evaluate the emotional content of presented stimuli; in the implicit mode, their attention was directed to other features of the stimulus. In the implicit mode, theta synchronization was most pronounced in the early processing stage, whereas in the explicit mode, it was more pronounced in the late processing stage. The early processing stage was more pronounced in men, whereas the late processing stage was more pronounced in women. Implications of these gender differences in emotion processing for well-documented differences in social behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)