Characterization of pedicel,paper, and larval silk from nest ofPolistes annularis (L.)

The pedicel, nest paper, and larval silk ofPolistes annularis nests were analyzed by high-resolution solid-state [¹³C]NMR. The pedicel was found to have a high nitrogen content (11%), and the NMR spectra indicated that it is a mixture of carbohydrate and protein. The pedicel protein has an amino acid composition that is very rich in glycine, alanine, serine, and proline (67% of identified residues), similar to that of some insect silks. Solid-state [¹³C]NMR indicated that the nest paper is composed predominantly of cellulose. Silk, spun by matureP. annularis larvae, was shown by [¹³C] NMR and amino acid analysis to be a protein very high in serine and alanine (53%), but the amino acid composition is distinct from that of the pedicel protein.     

Near-infrared analysis of whole kernel barley: comparison of three spectrometers

This study was conducted to develop calibration models for determining quality parameters of whole kernel barley using a rapid and nondestructive near-infrared (NIR) spectroscopic method. Two hundred and five samples of whole barley grains of three winter-habit types (hulled, malt, and hull-less) produced over three growing seasons and from various locations in the United States were used in this study. Among these samples, 137 were used for calibration and 68 for validation. Three NIR instruments with different resolutions, one Fourier transform instrument (4 cm(-1) resolution), and two dispersive instruments (8 nm and 10 nm bandpass) were utilized to develop calibration models for six components (moisture, starch, beta-glucan, protein, oil, and ash) and the results were compared. Partial least squares regression was used to build models, and various methods for preprocessing of spectral data were used to find the best model. Our results reveal that the coefficient of determination for calibration models (NIR predicted versus reference values) ranged from 0.96 for moisture to 0.79 for beta-glucan. The level of precision of the model developed for each component was sufficient for screening or classification of whole kernel barley, except for beta-glucan. The higher resolution Fourier transform instrument gave better results than the lower resolution instrument for starch and beta-glucan analysis. The starch model was most improved by the increased resolution. There was no advantage of using a higher resolution instrument over a lower resolution instrument for other components. Most of the components were best predicted using first-derivative processing, except for beta-glucan, where second-derivative processing was more informative and precise.     

The use of FT‐IR microspectroscopic mapping to study the effects of enzymatic retting of flax (Linum usitatissimum L) stems

Fourier transform infrared (FT‐IR) microspectroscopic mapping was investigated as a tool to study the effects of enzymatic retting of flax stems. The FT‐IR technique permitted the elucidation of the relative loss or changes in the distribution of key chemical components after treatment with enzymes or enzyme/chelator mixtures in association with visible changes in structure. Cross‐sections of Ariane flax stems were treated with SP 249 (a pectinase‐rich enzyme mixture from Novo Nordisk) at 0.5, 0.7 or 1.0 ml l^?1 concentration in pH 5 acetate buffer for 6 h at 40 °C. Flax stems treated with 0.5 or 0.7 ml l^?1 SP 249 and 50 mM oxalic acid as a chelator were also investigated by the technique. The results indicated that treatment with 0.5 ml l^?1 SP 249 alone was ineffective in releasing the fibre bundles from the surrounding tissue, but the release was increased by the addition of 50 mM oxalic acid as a likely chelator for the cations of pectate salts. However, the IR spectra of the bundles indicated that an insoluble oxalate salt remained on the tissue after this treatment. Increasing the concentration of SP 249 to 0.7 ml l^?1 plus 50 mM oxalic acid was effective in releasing the fibre bundles and generating some ultimate fibres with no detectable oxalate expectate salt residues. Increasing the SP 249 concentration to 1.0 ml l^?1 without using oxalic acid was effective in separating the fibre bundles into ultimate (individual) fibres, leaving no pectate salt residue and only a trace of pectic esters and/or acids. The use of infrared mapping, or so‐called chemical imaging, is shown to have advantages over visible imaging alone in that it can detect and locate the chemical species present after each treatment in relation to the anatomical features of the flax stem. This analytical tool shows promise as a technique by which to study the effects of enzymatic treatment of natural fibre materials. Published in 2002 for SCI by John Wiley & Sons, Ltd     

Influence of agitator design and catalyst concentration on partial hydrogenation of sunflower oil

In this study, lab‐scale hydrogenation of sunflower oil was conducted at 190 °C and 2 bar using two different catalyst types at varying concentrations and two different agitator designs (surface gassing and hollow shaft) at varying power inputs. At identical power input and reaction conditions, the reaction rate with the hollow‐shaft agitator was 1.68 times higher than with surface gassing agitation. The catalyst concentration had to exceed a certain feedstock‐dependent threshold value of 25 ppm Ni in order to start the reaction. At low catalyst concentration, the reaction rate increased proportionally with increasing catalyst concentration. When hydrogen consumption became higher than the available mass transfer provided by the agitation system, the reaction time became less dependent on the catalyst concentration. For the hollow‐shaft agitator, this situation was observed at a reaction rate of 3.7 ΔIV/min, where trans formation was at its maximum with more than 40% trans fatty acids in partially hydrogenated sunflower oil with IV 65. The region in which hydrogen mass transfer did not limit the reaction rate could be extended by more efficient agitation design or increased agitation power. In this way, productivity can be increased and trans formation can be controlled in a better way when compared to hydrogenation with a less efficient agitator.     

Isotopenhydrologische Methoden (2H, 18O) zur Bestimmung der Grundwasserneubildung in Trockengebieten: Potenzial und Grenzen

Grundwasser - Die Quantifizierung der Grundwasserneubildung in Trockengebieten stellt aufgrund klimatischer Gegebenheiten, mächtiger ungesättigter Zonen sowie hochangepasster Vegetation...     

Erkundung tiefer,bislang unbekannter semi-fossiler Grundwasserleiter im Kalahari-Becken (südliches Afrika)

Grundwasser - Semi-fossile Grundwasserleiter sind im Gegensatz zu fossilen Aquiferen noch an den hydrologischen Kreislauf angebunden und werden zu Teilen erneuert. In Afrika bilden diese Aquifere...     

Hydrogeochemische Hintergrundwerte der Grundw?sser Deutschlands als Web Map Service

One of the main objectives of the EC water framework directive is to ensure good chemical status for all groundwater bodies. For this reason the geological surveys of Germany have produced a nationwide map of the background values of groundwater. Only naturally occurring inorganic parameters were taken into account, including the relevant major and trace elements. Based on the hydrogeological map of Germany at the scale of 1:200,000 (HüK 200), and its delimited hydrogeological regions, a total of 186 hydrogeochemical units were defined and mapped geochemically. This involved collection of more than 52,000 groundwater samples in a database and allocation to their appropriate hydrogeochemical units. In order to separate anomalies within the data-sets from the underlying normal population, probability nets were used as a statistical tool. The procedure allowed to determine the normal populations of the investigated parameters within the hydrogeochemical units and to quantify them in the form of percentiles. The resulting hydrogeochemical background values are accessible through an internet web map service that includes an online map application. The main intention of this technical note is to inform the reader about the existing internet service, which necessitates some web-site content duplication.     

Hydrogeologie des Kabul-Beckens (Afghanistan), Teil II: Beschaffenheit des Grundwassers

Shallow groundwater is the main source for drinking water in Kabul. It comes from a multitude of shallow handpumped wells spread over the whole city area. The groundwater is characterised by slightly oxic redox conditions. Interactions with aquifer carbonates lead to high degrees of hardness and near-neutral pH. The mostly negative water budget of the Kabul basin results in strong evaporation which leads to an increase in salt content and some undesirable constituents, including borate. Several years of drought have aggravated this problem. The shallow groundwater in the city has received tremendous amounts of pollutants due to a lack of proper waste and wastewater disposal. Common indicators are elevated concentrations of nutrients such as nitrate and faecal bacteria. The high infant mortality can at least partially be attributed to insufficient water hygiene. Acid generated during the mineralization of the waste water is hidden due to the strong pH buffering capacity. Redox and pH conditions preclude significant mobilisation of trace metals and metalloids.