Comment

Conclusion  In such a situation the only approach possible, even for a prospective LCA study, is to aggregate data from the possible sources of delivery and to use this as an input to the study. Weidema states in his article that actual average data is more difficult to collect than data for a marginal situation. But this is no argument against using average data when this is what most correctly portrays the actual situation. We would argue that this is also the only correct approach for a global commodity, since this will be the real situation for any new product. The material going into it will potentially be an average of the existing material on the market.     

Scalable,two-stage,autoinduction of recombinant protein expression in E. coli utilizing phosphate depletion

We report the scalable production of recombinant proteins in Escherichia coli, reliant on tightly controlled autoinduction, triggered by phosphate depletion in the stationary phase. The method, reliant on engineered strains and plasmids, enables improved protein expression across scales. Expression levels using this approach have reached as high as 55% of the total cellular protein. The initial use of the method in instrumented fed-batch fermentations enables cell densities of ∼30 gCDW/L and protein titers up to 8.1 ± 0.7 g/L (∼270 mg/gCDW). The process has also been adapted to an optimized autoinduction media, enabling routine batch production at culture volumes of 20 μl (384-well plates), 100 μl (96-well plates), 20 ml, and 100 ml. In batch cultures, cell densities routinely reach ∼5–7 gCDW/L, offering protein titers above 2 g/L. The methodology has been validated with a set of diverse heterologous proteins and is of general use for the facile optimization of routine protein expression from high throughput screens to fed-batch fermentation.     

Negative impact of manganese on honeybee foraging

Anthropogenic accumulation of metals such as manganese is a well-established health risk factor for vertebrates. By contrast, the long-term impact of these contaminants on invertebrates is mostly unknown. Here, we demonstrate that manganese ingestion alters brain biogenic amine levels in honeybees and fruit flies. Furthermore, we show that manganese exposure negatively affects foraging behaviour in the honeybee, an economically important pollinator. Our findings indicate that in addition to its direct impact on human health, the common industrial contaminant manganese might also have indirect environmental and economical impacts via the modulation of neuronal and behavioural functions in economically important insects.     

Effect of low pass filtering on joint moments from inverse dynamics: implications for injury prevention

Analyses of joint moments are important in the study of human motion, and are crucial for our understanding of e.g. how and why ACL injuries occur. Such analyses may be affected by artifacts due to inconsistencies in the equations of motion when force and movement data are filtered with different cut-off frequencies. The purpose of this study was to quantify the effect of these artifacts, and compare joint moments calculated with the same or different cut-off frequency for the filtering of force and movement data. 123 elite handball players performed sidestep cutting while the movement was recorded by eight 240 Hz cameras and the ground reaction forces were recorded by a 960 Hz force plate. Knee and hip joint moments were calculated through inverse dynamics, with four different combinations of cut-off frequencies for signal filtering: movement 10 Hz, force 10 Hz, (10-10); movement 15 Hz, force 15 Hz; movement 10 Hz, force 50 Hz (10-50); movement 15 Hz, force 50 Hz. The results revealed significant differences, especially between conditions with different filtering of force and movement. Mean (SD) peak knee abduction moment for the 10-10 and 10-50 condition were 1.27 (0.53) and 1.64 (0.68) Nm/kg, respectively. Ranking of players based on knee abduction moments were affected by filtering condition. Out of 20 players with peak knee abduction moment higher than mean+1S D with the 10-50 condition, only 11 were still above mean+1 SD when the 10-10 condition was applied. Hip moments were very sensitive to filtering cut-off. Mean (SD) peak hip flexion moment was 3.64 (0.75) and 5.92 (1.80) under the 10-10 and 10-50 conditions, respectively. Based on these findings, force and movement data should be processed with the same filter. Conclusions from previous inverse dynamics studies, where this was not the case, should be treated with caution.     

Radical formation in pyrimidine bases after X,proton and alpha-particle irradiation

Single crystals of anhydrous thymine (Ta) and cytosine monohydrate (Cm) were irradiated at room temperature using X rays, 20 MeV protons and 35 MeV alpha particles, and the relative distributions of the various radiation-induced stable radicals in the crystals were investigated. These two crystal systems were chosen because of systematic differences in their molecular packing and hydrogen-bonding network. The radicals stabilized in these systems have previously been identified and analyzed by several authors. Experimental EPR spectra could thus be reconstructed based on simulated benchmark spectra using a fitting procedure, yielding the relative amounts of the different radical species. It was found that the relative amounts of a given radical species varied with the type of radiation used, with differences being most prominent between alpha particles and protons or X rays. In Ta, an increased production of hydrogen addition or abstraction radicals was found after exposure to alpha particles. These radicals are believed to be formed predominantly from superexcited states, resulting from the higher density of ionizations along the track of the alpha particle. A corresponding reduction in radicals derived from proton transfer reactions was observed in comparison with exposure to protons or X rays. In Cm, the differences were smaller than for Ta. This is probably due to differences in the arrangement of the crystal lattice between the two systems, with Cm having an extended hydrogen-bonding network promoting fast proton transfers after ionization. Most interesting, however, was the observation that more than 50% of the radical population in Cm not could be accounted for by known radical species. The population with an unknown origin was represented with a broad singlet, having a line width of 1.5 mT and a g value of 2.0045, in the spectral reconstruction procedure.     

Alanine radicals,part 4: relative amounts of radical species in alanine dosimeters after exposure to 6-19 MeV electrons and 10 kV-15 MV photons

The amino acid l-alpha-alanine can be used for high-precision dosimetry over a wide dose range, using EPR spectroscopy for monitoring radical concentrations. It is important, however, to understand the underlying composition of the observed EPR spectrum. In previous work, it was shown that the EPR signal from irradiated alanine consists of at least three different radical species, with the relative importance of each of these being almost independent of absorbed dose. However, it was not known whether the relative importance of each radical is independent of the radiation quality responsible for the EPR signal. In the present work, the relative contributions of the different radical species to the total EPR signal from alanine dosimeters irradiated with 6-19 MeV electrons and 10 kV-15 MV photons at a dose of 10 Gy were examined. By spectrum reconstruction using benchmark spectra generated from a simulation procedure, the relative amounts of the three different radical species were shown to be virtually independent of these radiation beam qualities.