Root colonisation by the arbuscular mycorrhizal fungus Glomus intraradices alters the quality of strawberry fruits (Fragaria × ananassa Duch.) at different nitrogen levels

BACKGROUND: Arbuscular mycorrhizal fungi (AMF) increase the uptake of minerals from the soil, thus improving the growth of the host plant. Nitrogen (N) is a main mineral element for plant growth, as it is an essential component of numerous plant compounds affecting fruit quality. The availability of N to plants also affects the AMF–plant interaction, which suggests that the quality of fruits could be affected by both factors. The objective of this study was to evaluate the influence of three N treatments (3, 6 and 18 mmol L^?1) in combination with inoculation with the AMF Glomus intraradices on the quality of strawberry fruits. The effects of each factor and their interaction were analysed. RESULTS: Nitrogen treatment significantly modified the concentrations of minerals and some phenolic compounds, while mycorrhization significantly affected some colour parameters and the concentrations of most phenolic compounds. Significant differences between fruits of mycorrhizal and non‐mycorrhizal plants were found for the majority of phenolic compounds and for some minerals in plants treated with 6 mmol L^?1 N. The respective values of fruits of mycorrhizal plants were higher. CONCLUSION: Nitrogen application modified the effect of mycorrhization on strawberry fruit quality. Copyright © 2010 Society of Chemical Industry     

Short communication: Fat-soluble vitamin and mineral status of milk replacer-fed dairy calves: Effect of growth rate during the preruminant period

Effects of growth rate on fat-soluble vitamin and macro- and micromineral concentrations in the circulation of preruminant dairy calves were evaluated. Dietary treatments were designed to achieve 3 targeted rates of gain [no growth (NG) = 0.0 kg/d; low growth (LG) = 0.55 kg/d; or high growth (HG) = 1.2 kg/d] over a 7-wk period. Milk replacer (MR) intakes necessary to achieve these growth rates were estimated using the National Research Council's Nutrient Requirements of Dairy Cattle calf model computer program. All of the calves were fed a 30% crude protein, 20% fat MR reconstituted to 14% dry matter. The diets were formulated to ensure that protein was not a limiting nutrient. No-growth and LG calves were supplemented additionally with vitamins A, D, and E to compensate for treatment differences in dry matter intake relative to the HG calves; however, no attempt was made to adjust mineral intake based on MR consumption. Growth rates for NG (0.11 kg/d), LG (0.58 kg/d), and HG (1.16 kg/d) calves differed during the study. Health was minimally affected by growth rate and this was reflected by comparable and relatively low serum haptoglobin concentrations in all calves during the 7-wk period. Concentrations of serum retinol, 25-(OH)-vitamin D₃, and zinc were unaffected by growth rate. The HG calves had lower RRR-α-tocopherol concentrations than NG and LG calves at wk 7, suggesting that the increased growth rate of HG calves was associated with increased utilization of vitamin E. Serum concentrations of all vitamins increased with age. Copper, calcium, and phosphorous concentrations in HG calves exceeded those in LG and NG calves during the latter weeks of the study, likely because of increased MR intake by HG calves. Fat-soluble vitamin and mineral concentrations for all treatment groups remained within ranges considered normal for preruminant calves.     

Prediction of the resonance characteristics of combustion chambers on the basis of large-eddy simulation

In the last few years intensive experimental investigations were performed at the University of Karlsruhe to develop an analytical model for the Helmholtz resonator-type combustion system. In the present work the resonance characteristics of a Helmholtz resonator-type combustion chamber were investigated using large-eddy simulations (LES), to understand better the flow effects in the chamber and to localize the dissipation. In this paper the results of the LES are presented, which show good agreement with the experiments. The comparison of the LES study with the experiments sheds light on the significant role of the wall roughness in the exhaust gas pipe.     

FLOCCULATION OF ASPHALTENES AT HIGH PRESSURE. I. EXPERIMENTAL DETERMINATION OF THE ONSET OF FLOCCULATION

The influence of pressure on the onset of flocculation of asphaltenes was investigated in the pressure range from 1 to 300 bar and at temperatures of 55, 75, and 100°C. Methane was employed as gas component, and i-octane was used as precipitant. The onset of flocculation was determined with a light intensity meter. Three crude oils of different provenance were chosen for the investigations. The crude oils were stabilized in a rotary evaporator at 50 mbar and 180°C, and a part of stabilized products were mixed with different amounts of n-octane or methylcyclohexane. The dependence of the onset of flocculation on the pressure is analogous for all products. The required volume of i-octane decreases strongly with pressure up to 100 bar. Above 100 bar the influence of the pressure diminishes. This dependence corresponds with the solubility of methane in crude oil products. The amount of light hydrocarbons determines the position of the pressure dependence of the onset of flocculation. Without the addition of i-octane, the onset of flocculation could not be ascertained. The observed kinetics of flocculation depends on the asphaltene content as well as on the pressure. The influence of dispersing agents was also examined.     

Cell biology of the adipokinetic hormone-producing neurosecretory cells in the locust corpus cardiacum.

The adipokinetic cells are neuron-like unipolar cells, the cell bodies and cell processes of which are intermingled within the glandular part of the corpus cardiacum. In Schistocerca gregaria, they produce two adipokinetic hormones, AKH-I and -II, whereas in Locusta migratoria an additional hormone, AKH-III, is present. The three AKHs are produced by the same cells and are co-localized in secretory granules. The biosynthesis and processing of the AKH prohormones to the bioactive hormones, which has been elucidated in detail for AKH-I and -II in S. gregaria, takes less than 75 min and goes on continuously. In older locusts in particular, the adipokinetic cells contain intracisternal granules, widely dilated cisternae of the rough endoplasmic reticulum, which function as stores of prohormones of AKH-I and -II, not of AKH-III. The adipokinetic cells are subjected to regulation by a number of neural and humoral substances, neural influences coming from secretomotor cells in the lateral part of the protocerebrum. Flight activity is the only natural stimulus unequivocally shown to induce the release of AKHs, which in L. migratoria results in parallel secretion of all three AKHs. During secretory stimulation, young secretory granules containing newly synthesized hormones are preferentially released over older granules. Secretory stimulation is not accompanied by a clear increase in the levels of the AKH mRNAs and the AKH prohormones and in the rate of synthesis of the (pro-)AKHs. Apparently, a coupling between release and biosynthesis of the AKHs in the adipokinetic cells is very loose or does not even exist.     

8 Gbits/s inductorless transimpedance amplifier in 90 nm CMOS technology

This work presents the design and the measured performance of a 8 Gb/s transimpedance amplifier (TIA) fabricated in a 90 nm CMOS technology. The introduced TIA uses an inverter input stage followed by two common-source stages with a 1.5 kΩ feedback resistor. The TIA is followed by a single-ended to differential converter stage, a differential amplifier and a 50 Ω differential output driver to provide an interface to the measurement setup. The optical receiver shows a measured optical sensitivity of ?18.3 dBm for a bit error rate = 10^?9. A gain control circuitry is integrated with the TIA to increase its input photo-current dynamic range (DR) to 32 dB. The TIA has an input photo-current range from 12 to 500 μA without overloading. The stability is guaranteed over the whole DR. The optical receiver achieves a transimpedance gain of 72 dBΩ and 6 GHz bandwidth with 0.3 pF total input capacitance for the photodiode and input PAD. The TIA occupies 0.0036 mm² whereas the complete optical receiver occupies a chip area of 0.46 mm². The power consumption of the TIA is only 12 mW from a 1.2 V single supply voltage. The complete chip dissipates 60 mW where a 1.6 V supply is used for the output stages.     

Periparturient hypocalcemia in cows: prevention using intramuscular parathyroid hormone

Intravenously administered parathyroid hormone has recently been reported to prevent parturient paretic hypocalcemia in dairy cows. In the present study, Parathyroid hormone was administered intramuscularly prior to parturition to study its effects on Ca homeostasis and the incidence of periparturient hypocalcemia. Ten Holstein cows were fed a high Ca diet prepartum to predispose them to parturient paretic hypocalcemia. Five cows received intramuscular injections of synthetic bovine parathyroid hormone three times per day beginning about 6 d before parturition and continuing at a reduced dose for about 6 d after parturition. One of five control cows developed parturient paresis, and all five control cows exhibited hypocalcemia within 24 h of calving. None of the treated cows became paretic, and plasma calcium was normal or slightly elevated in these cows during the first 24 h after calving. Parathyroid hormone administration increased plasma concentrations of 1,25-dihydroxyvitamin D and hydroxyproline prior to parturition, suggesting that both intestinal Ca absorption and bone calcium resorption were increased by administration of the hormone. One hormone-treated cow became recumbent and required euthanasia. Although metastatic calcification of soft tissues was not observed, the death of this cow raises the possibility that there are unknown side effects of parathyroid hormone when administered intramuscularly.     

Compact versatile thermooptical space switch based on beam steeringby a waveguide array

We present the implementation of an optical space switching concept based on thermooptic beam steering in an arrayed waveguide grating. Individual addressing of heaters on the array waveguides enables flexible switching of input signals to output waveguide channels. The switch can be used either as a 1-to-8 switch or as multiple parallel 1-to-4, 1-to-3, or 1-to-2 switches. For the implementation we used high-refractive-index SiON-SiO₂ planar waveguide technology, which allows the realization of compact devices using small bending radii. We achieved isolations of the “off'” channels with respect to the “on” channel of up to 29 dB for a 1-to-3 switch or better than 22 dB for all “off” waveguides for a 1-to-8 switch     

Symposium der Arbeitsgruppe Wissenschafts-geschichte zur Geschichte der Kaiser-Wilhelm-/Max-Planck-Gesellschaft

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