Cobble substrate in a surface bypass reduces bypass acceptance by common roach Rutilus rutilus

Historically, ecological engineered solutions for fish passage across anthropogenic barriers in rivers has mainly focused on facilitating upstream passage for long-migrating diadromous fish, such as salmonids. More recently, passage solutions have shifted their focus to a more holistic ecological perspective, allowing passage for species with different swimming capacity, both upstream and downstream. This experiment investigated whether the addition of cobble in the passageway of a surface bypass could facilitate downstream movement of a cyprinid fish, the common roach Rutilus rutilus. Surface bypasses were constructed in large experimental flumes and roach were released into the flumes and monitored for bypass passage using PIT-telemetry through 11-h night-trials. Behavior was scored using four continuously-recording video cameras at the bypass construction. There was a negative effect of substrate-treatment on the passage rate through the bypass. The majority of the fish in the No substrate treatment had successfully passed within 4 h, while a lesser proportion of the fish in the Substrate treatment had done so (additional fish in the latter treatment passed later in the trials). Fish exposed to cobble substrate in the bypass passageway showed more avoidance-like behaviors at the ramp section of the bypass and tended to return back upstream more often than the fish in the no-substrate control trials. When reaching the passageway, the substrate-exposed fish expressed no behaviors that could be indicative of reduced passage success, as compared to controls. We conclude that passage was not hindered by the presence of cobble substrate, but passage was delayed due to avoidance behavior at the bypass ramp when cobble substrate was present. Based on these results, the addition of cobble substrate in a surface bypass cannot be recommended as a measure to facilitate the downstream passage performance of the common roach through surface bypasses

Fish biodiversity in different types of tributary mouths located within impounded sections of Swedish boreal rivers

Large boreal rivers in Sweden are generally impounded by hydropower dams and a large proportion of main stem shallow flowing habitats have been lost. Tributaries often contain the last undisturbed habitats and could be important for the conservation of species diversity. In particular, tributary mouth areas could be biodiversity hot-spots, due to their vicinity to the main stem and favorable environmental conditions. In this study, we investigate whether tributary mouth areas in two impounded boreal rivers (Ume River and Lule River) could be regarded as biodiversity hot-spots for fish. Based on standardized electrofishing in 20 tributary mouths, we find that overall fish diversity is generally low. The highest species richness and diversity was found in mouth areas dominated by intermediate substrate sizes (gravel – cobble). Few, if any, species were found in areas where fine sediments (smaller than sand) dominated. The tributary mouth areas had similar species richness and diversity as areas in the tributaries located 1-km upstream of the mouth, but the fish community composition often differed between these two types of sites. Management action favoring fish diversity in the tributary mouth areas could include protection or rehabilitation of areas dominated by medium sized substrate and reduction of erosion and transport of fine sediments in the tributaries. Overall, we find no support for tributary mouths being hot-spots for fish biodiversity and while some patterns in diversity gives hints on suitable management action, it is important to further understand impacts in tributaries and their mouths and the temporal dynamics of the fish community. Aggradation Boreal rivers Fish biodiversity River morphology River sediment size Tributary confluencepublishedVersio

Deep Search for Glycine Conformers in Barnard 5

One of the most fundamental hypotheses in astrochemistry and astrobiology states that crucial biotic molecules like glycine (NH$_2$CH$_2$COOH) found in meteorites and comets are inherited from early phases of star formation. Most observational searches for glycine in the interstellar medium have focused on warm, high-mass molecular cloud sources. However, recent studies suggest that it might be appropriate to shift the observational focus to cold, low-mass sources. We aim to detect glycine towards the so-called methanol hotspot in the Barnard 5 dark cloud. The hotspot is a cold source ($T_\mathrm{gas}\approx 7.5$ K) with yet high abundances of complex organic molecules (COMs) and water in the gas phase. We carried out deep, pointed observations with the Onsala 20m telescope, targeting several transitions of glycine conformers I and II (Gly-I and Gly-II) in the frequency range $70.2$-$77.9$ GHz. No glycine lines are detected towards the targeted position, but we use a line stacking procedure to derive sensitive abundance upper limits w.r.t. H$_2$ for Gly-I and Gly-II, i.e. $\leq(2$-$5)\times10^{-10}$ and $\leq(0.7$-$3)\times10^{-11}$, respectively. The obtained Gly-II upper limits are the most stringent for a cold source, while the Gly-I upper limits are mostly on the same order as previously measured limits. The measured abundances w.r.t. H$_2$ of other COMs at the B5 methanol hotspot range from $2\times10^{-10}$ (acetaldehyde) to $2\times10^{-8}$ (methanol). Hence, based on a total glycine upper limit of $(2$-$5)\times10^{-10}$, we cannot rule out that glycine is present but undetected.Comment: 12 pages, 7 figure

Observational tests of interstellar methanol formation

Context. It has been established that the classical gas-phase production of interstellar methanol (CH3OH) cannot explain observed abundances. Instead it is now generally thought that the main formation path has to be by successive hydrogenation of solid CO on interstellar grain surfaces. Aims: While theoretical models and laboratory experiments show that methanol is efficiently formed from CO on cold grains, our aim is to test this scenario by astronomical observations of gas associated with young stellar objects (YSOs). Methods: We have observed the rotational transition quartets J = 2K - 1K of 12CH3OH and 13CH3OH at 96.7 and 94.4 GHz, respectively, towards a sample of massive YSOs in different stages of evolution. In addition, the J = 1-0 transitions of 12C18O and 13C18O were observed towards some of these sources. We use the 12C/13C ratio to discriminate between gas-phase and grain surface origin: If methanol is formed from CO on grains, the ratios should be similar in CH3OH and CO. If not, the ratio should be higher in CH3OH due to 13C fractionation in cold CO gas. We also estimate the abundance ratios between the nuclear spin types of methanol (E and A). If methanol is formed on grains, this ratio is likely to have been thermalized at the low physical temperature of the grain, and therefore show a relative over-abundance of A-methanol. Results: We show that the 12C/13C isotopic ratio is very similar in gas-phase CH3OH and C18O, on the spatial scale of about 40", towards four YSOs. For two of our sources we find an overabundance of A-methanol as compared to E-methanol, corresponding to nuclear spin temperatures of 10 and 16 K. For the remaining five sources, the methanol E/A ratio is less than unity. Conclusions: While the 12C/13C ratio test is consistent with methanol formation from hydrogenation of CO on grain surfaces, the result of the E/A ratio test is inconclusive

A scalable adenovirus production process, from cell culture to purified bulk

Adenovirus (AdV) vectors are commonly used in cancer gene therapy trials, evaluated in gene therapy and used as vaccines for various diseases. AdV vectors are well studied and are suitable as vaccine vectors due to their ability to infect different cell types, remain episomal and produce stable high titer material. Manufacturing of safe and efficacious clinical-grade virus relies on a scalable and cost-effective production process. In this study, we have combined experimental work and process economy calculations, from AdV production in cell culture to purified bulk product up to 10L scale. An efficient and scalable process for AdV production was developed by evaluation of each process step. The most studied vector is serotype 5, making this a suitable system for process development of AdV vectors. Human AdV5 expressing the green fluorescent protein (GFP) was used for process development. First, suspension HEK 293 cells adapted to serum-free cell culture medium were optimized for AdV production and evaluated in different single use bioreactor systems. Tween 20 was used for cell lysis as a replacement for the traditionally used Triton X-100 (now on the Authorization list (Annex XIV) of REACH, the regulation on Registration, Evaluation, Authorization and restriction of Chemicals). A residual Tween 20 assay with low detection limit was set-up. Filters and conditions for clarification, concentration and buffer exchange by tangential flow filtration were optimized. Anion exchange based capture step alternatives were compared, including different chromatography resins and membrane formats. Finally, core bead technology was evaluated as an alternative to size exclusion chromatography for the polishing step before the final formulation. Analytical methods for virus titer are challenging and depend on purity and quality of the sample. For total virus titer, qPCR and HPLC methods were used. Furthermore, a method based on surface plasmon resonance (Biacore) was developed for analysis of adenovirus titer. For infectious virus titer, we have used a cell based assay with automatic image analysis. Based on analytical data different downstream process alternatives were compared regarding load capacity, recovery and purity and we propose a robust and scalable process with a favorable process economy. Please click Additional Files below to see the full abstract

Ground-state ammonia and water in absorption towards Sgr B2

Context. Observations of transitions to the ground-state of a molecule are essential to obtain a complete picture of its excitation and chemistry in the interstellar medium, especially in diffuse and/or cold environments. For the important interstellar molecules H₂O and NH₃, these ground-state transitions are heavily absorbed by the terrestrial atmosphere, hence not observable from the ground. Aims: We attempt to understand the chemistry of nitrogen, oxygen, and their important molecular forms, NH₃ and H₂O in the interstellar medium of the Galaxy. Methods: We have used the Odin* submillimetre-wave satellite telescope to observe the ground state transitions of ortho-ammonia and ortho-water, including their ¹⁵N, ¹⁸O, and ¹⁷O isotopologues, towards Sgr B2. The extensive simultaneous velocity coverage of the observations, >500 km s^-1, ensures that we can probe the conditions of both the warm, dense gas of the molecular cloud Sgr B2 near the Galactic centre, and the more diffuse gas in the Galactic disk clouds along the line-of-sight. Results: We present ground-state NH₃ absorption in seven distinct velocity features along the line-of-sight towards Sgr B2. We find a nearly linear correlation between the column densities of NH₃ and CS, and a square-root relation to N₂H⁺. The ammonia abundance in these diffuse Galactic disk clouds is estimated to be about 0.5–1 × 10^-8, similar to that observed for diffuse clouds in the outer Galaxy. On the basis of the detection of H_218O absorption in the 3 kpc arm, and the absence of such a feature in the H_217O spectrum, we conclude that the water abundance is around 10-7, compared to ~10-8 for NH3. The Sgr B2 molecular cloud itself is seen in absorption in NH₃, 15NH₃, H₂O, H_218O, and H_217O, with emission superimposed on the absorption in the main isotopologues. The non-LTE excitation of NH3 in the environment of Sgr B2 can be explained without invoking an unusually hot (500 K) molecular layer. A hot layer is similarly not required to explain the line profiles of the 11,0≥ts10,1 transition from H2O and its isotopologues. The relatively weak 15NH3 absorption in the Sgr B2 molecular cloud indicates a high [ 14N/15N] isotopic ratio >600. The abundance ratio of H_218O and H_217O is found to be relatively low, 2.5–3. These results together indicate that the dominant nucleosynthesis process in the Galactic centre is CNO hydrogen burning. Odin is a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes), and the centre National d'Études Spatiales (CNES, France). The Swedish Space Corporation (SSC) was the industrial prime contractor and is also responsible for the satellite operation