Microbiological quality control of a cage washing machine by means of a thin film culture system (PetrifilmTM)

Washing machine effectiveness is dependent on treatment of cage surface with hot water containing detergent. The temperature of the washing chamber will not reflect the degree of treatment of each individual cage. Bacteriological testing ofcage surface will give a true indication of residual contamination. This study describes the use of rehydratable contact films to harvest and culture residual bacteria. The method registers numbers of colonies retrieved from the surface. It does nottype the bacteria and is as such a non-specific method. The study reveals that the machine in question was effective and that no bacteria were found following a normal cycle. A machine breakdown was demonstrated before the mechanicalcause was uncovered

Molecular Carbon Chains and Rings in TMC-1

We present mapping results in several rotational transitions of HC3N, C6H, both cyclic and linear C3H2 and C3H, towards the cyanopolyyne peak of the filamentary dense cloud TMC-1 using the IRAM 30m and MPIfR 100m telescopes. The spatial distribution of the cumulene carbon chain propadienylidene H2C3 (hereafter l-C3H2) is found to deviate significantly from the distributions of the cyclic isomer c-C3H2, HC3N, and C6H which in turn look very similar. The cyclic over linear abundance ratio of C3H2 increases by a factor of 3 across the filament, with a value of 28 at the cyanopolyyne peak. This abundance ratio is an order of magnitude larger than the range (3 to 5) we observed in the diffuse interstellar medium. The cyclic over linear abundance ratio of C3H also varies by ~2.5 in TMC-1, reaching a maximum value (13) close to the cyanopolyyne peak. These behaviors might be related to competitive processes between ion-neutral and neutral-neutral reactions for cyclic and linear species.Comment: Accepted for publication in The Astrophysical Journal, part I. 24 pages, including 4 tables, 7 figures, and figure caption

Evolution of an elliptical bubble in an accelerating extensional flow

Mathematical models that describe the dynamical behavior of a thin gas bubble embedded in a glass fiber during a fiber drawing process have been discussed and analyzed. The starting point for the mathematical modeling was the equations presented in [1] for a glass fiber with a hole undergoing extensional flow. These equations were reconsidered here with the additional reduction that the hole, i.e. the gas bubble, was thin as compared to the radius of the fiber and of finite extent. The primary model considered was one in which the mass of the gas inside the bubble was fixed. This fixed-mass model involved equations for the axial velocity and fiber radius, and equations for the radius of the bubble and the gas pressure inside the bubble. The model equations assumed that the temperature of the furnace of the drawing tower was known. The governing equations of the bubble are hyperbolic and predict that the bubble cannot extend beyond the limiting characteristics specified by the ends of the initial bubble shape. An analysis of pinch-off was performed, and it was found that pinch-off can occur, depending on the parameters of the model, due to surface tension when the bubble radius is small. In order to determine the evolution of a bubble, a numerical method of solution was presented. The method was used to study the evolution of two different initial bubble shapes, one convex and the other non-convex. Both initial bubble shapes had fore-aft symmetry, and it was found that the bubbles stretched and elongated severely during the drawing process. For the convex shape, fore-aft symmetry was lost in the middle of the drawing process, but the symmetry was re-gained by the end of the drawing tower. A small amount of pinch-off was observed at each end for this case, so that the final bubble length was slightly shorter than its theoretical maximum length. For the non-convex initial shape, pinch-off occurred in the middle of the bubble resulting in two bubbles by the end of the fiber draw. The two bubbles had different final pressures and did not have fore-aft symmetry. An extension of the fixed-mass model was considered in which the gas in the bubble was allowed to diffuse into the surrounding glass. The governing equations for this leaky-mass model were developed and manipulated into a form suitable for a numerical treatment

Biodistribution et toxicité des nanocapsules chargées en 188Re après injection intratumorale par convection enhanced delivery chez la souris

Objectifs Déterminer la faisabilité, l’intérêt et la toxicité hématologique de l’administration intratumorale par convection enhanced delivery (CED) de nanocapsules chargées en 188Re (NCL-188Re). Matériels et méthodes L’étude de biodistribution des NCL-188Re vs perrhénate (188ReO4−) a été réalisée sur des souris nude (n = 30). Les animaux ont été séparés en 2 groupes : injection intratumorale de 188ReO4− pour le premier groupe (n = 15, 3 MBq) et de NCL-188Re pour le second groupe (n = 15, 3 MBq). Les animaux ont été sacrifiés à 1 h (n = 10), 24 h (n = 10) et 72 h (n = 10) après l’injection, les organes prélevés et comptés. La toxicité hématologique des NCL-188Re a été évaluée par prises de sang de 50 μL (sinus rétro-orbitaire) réalisées à j2, j7, j14 et j21 après traitement par NaCl (n = 4), NCL-188Re (3 MBq, n = 4), NCL-188Re (6 MBq, n = 4) et NCL-188Re (12 MBq, n = 4). Résultats La vectorisation par NCL a permis de limiter l’élimination urinaire du 188Re puisque dès 24 h post-IV 0,1 ± 0,1 % de la dose injectée (%D.I.) vs 81,9 ± 7,5 % D.I. sont retrouvés dans les urines pour les formes NCL188Re-SSS et 188ReO4-, respectivement, (p = 0,016). Celle-ci permet également de retrouver une activité significativement supérieure dans la tumeur à tous les temps de l’étude. L’administration unique de NCL-188Re a induit une toxicité modérée pour les activités injectées les plus élevées (12 MBq) se manifestant principalement par une thrombopénie transitoire de nadir j14–j18. Il n’a pas été observé de toxicité au niveau des autres lignées cellulaires pour les activités administrées de 3 et 6 MBq. Conclusions Les résultats obtenus montrent la faisabilité de l’injection intratumorale par CED et l’intérêt de la vectorisation du 188Re par les NCL. Les premiers signes de toxicité hématologiques sont en faveur du fractionnement des doses administrées et d’un meilleur ciblage par fonctionnalisation des NCL aux oestrogènes pour permettre une meilleure rétention tumorale

Revisiting the S-matrix approach to the open superstring low energy effective lagrangian

The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic ${\alpha'}^N$ order terms, it is necessary to know the open string (tree level) $(N+2)$-point amplitude of massless bosons, at least expanded at that order in $\alpha'$. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring $n$-point amplitude is needed to find all the ${\alpha'}^N$ order terms. In this `revisited' S-matrix approach we have checked that, at least up to ${\alpha'}^4$ order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the $N$-point amplitudes and that important informations can be inferred, at least up to ${\alpha'}^4$ order, by only using the (tree level) 4-point amplitude.Comment: 34 pages, 3 figure, Submitted on Aug 4, 2012, Published on Oct 15, 201

Mapping the cellular landscape of Atlantic salmon head kidney by single cell and single nucleus transcriptomics

Single-cell transcriptomics is the current gold standard for global gene expression profiling, not only in mammals and model species, but also in non-model fish species. This is a rapidly expanding field, creating a deeper understanding of tissue heterogeneity and the distinct functions of individual cells, making it possible to explore the complexities of immunology and gene expression on a highly resolved level. In this study, we compared two single cell transcriptomic approaches to investigate cellular heterogeneity within the head kidney of healthy farmed Atlantic salmon (Salmo salar). We compared 14,149 cell transcriptomes assayed by single cell RNA-seq (scRNA-seq) with 18,067 nuclei transcriptomes captured by single nucleus RNA-Seq (snRNA-seq). Both approaches detected eight major cell populations in common: granulocytes, heamatopoietic stem cells, erythrocytes, mononuclear phagocytes, thrombocytes, B cells, NK-like cells, and T cells. Four additional cell types, endothelial, epithelial, interrenal, and mesenchymal cells, were detected in the snRNA-seq dataset, but appeared to be lost during preparation of the single cell suspension submitted for scRNA-seq library generation. We identified additional heterogeneity and subpopulations within the B cells, T cells, and endothelial cells, and revealed developmental trajectories of heamatopoietic stem cells into differentiated granulocyte and mononuclear phagocyte populations. Gene expression profiles of B cell subtypes revealed distinct IgM and IgT-skewed resting B cell lineages and provided insights into the regulation of B cell lymphopoiesis. The analysis revealed eleven T cell sub-populations, displaying a level of T cell heterogeneity in salmon head kidney comparable to that observed in mammals, including distinct subsets of cd4/cd8-negative T cells, such as tcrγ positive, progenitor-like, and cytotoxic cells. Although snRNA-seq and scRNA-seq were both useful to resolve cell type-specific expression in the Atlantic salmon head kidney, the snRNA-seq pipeline was overall more robust in identifying several cell types and subpopulations. While scRNA-seq displayed higher levels of ribosomal and mitochondrial genes, snRNA-seq captured more transcription factor genes. However, only scRNA-seq-generated data was useful for cell trajectory inference within the myeloid lineage. In conclusion, this study systematically outlines the relative merits of scRNA-seq and snRNA-seq in Atlantic salmon, enhances understanding of teleost immune cell lineages, and provides a comprehensive list of markers for identifying major cell populations in the head kidney with significant immune relevance.</p