Ventilation with "clinically relevant" high tidal volumes does not promote stretch-induced injury in the lungs of healthy mice

OBJECTIVE: Ventilator-induced lung injury is a crucial determinant of the outcome of mechanically ventilated patients. Increasing numbers of mouse studies have identified numerous pathways and mediators that are modulated by ventilation, but it is conceptually difficult to reconcile these into a single paradigm. There is substantial variability in tidal volumes used in these studies, and no certainty about the pathophysiology that such varied models actually represent. This study was designed to investigate whether ventilation strategies ranging from ‘very high’ to more ‘clinically-relevant’ tidal volumes induce similar pathophysiologies in healthy mice, or represent distinct entities. DESIGN: In vivo study. SETTING: University research laboratory. SUBJECTS: C57/Bl6 mice. INTERVENTIONS: Anesthetised mice were ventilated with various tidal volumes up to 40ml/kg. MEASUREMENTS AND MAIN RESULTS: Respiratory system compliance and arterial blood gases were used to evaluate physiological parameters of injury. Lung wet:dry weight ratio, lavage fluid protein and cytokines were used to assess pulmonary edema and inflammation. All ventilation strategies induced changes in respiratory system compliance, although the pattern of change was unique for each strategy. 10ml/kg and 40ml/kg ventilation also induced decreases in arterial pO(2) and blood pressure. Any physiological changes induced during the 10, 20 and 30ml/kg strategies were largely reversed by recruitment maneuvers at the end of the protocol. Markers of pulmonary edema and inflammation indicated that only 40ml/kg induced substantial increases in both, consistent with development of lung injury. CONCLUSIONS: Tidal volumes up to 20ml/kg are unlikely to induce substantial lung over-stretch in models using healthy, young mice. Signs of injury/inflammation using such models are likely to result from other factors, particularly alveolar derecruitment and atelectasis. The results of such studies may need to be re-evaluated before clinical relevance can be accurately determined

Lines on a map: conservation units, meta-population dynamics, and recovery of woodland caribou in Canada

Delineating conservation units is a fundamental step in recovery planning for endangered species. Yet, challenges remain in the application and validation of scientifically evaluated conservation units in management practice. The Canadian government makes use of Designatable Units (DUs) as the primary conservation unit under their Species‐at‐Risk Act. DUs must be ecologically discrete and have demonstrated evolutionary significance, which, in the case of woodland caribou (Rangifer tarandus caribou), has led to the definition of multiple DUs across Canada. Simultaneously, Environment and Climate Change Canada has released two recovery strategies affecting four DUs, wherein DUs are subdivided into smaller conservation units. However, the two recovery strategies adopt different definitions for the conservation unit. For the Boreal DU, the Local Population is considered the conservation unit for recovery management, whereas for Southern Mountain DU, the conservation unit for recovery is the subpopulation, which may or may not be comprised of several Local Populations. The scientific rationale for the difference between recovery strategies is unclear, not necessarily supported by genetic or demographic evidence, and highlights a policy challenge facing caribou conservation. We argue that the current emphasis on protecting subpopulations within a DU might be inconsistent and unviable for recovery planning. Instead, the recognition and emphasis on maintaining meta‐population dynamics within DUs is essential and currently underutilized in the long‐term recovery of woodland caribou in Canada

Interval Selection in the Streaming Model

A set of intervals is independent when the intervals are pairwise disjoint. In the interval selection problem we are given a set $\mathbb{I}$ of intervals and we want to find an independent subset of intervals of largest cardinality. Let $\alpha(\mathbb{I})$ denote the cardinality of an optimal solution. We discuss the estimation of $\alpha(\mathbb{I})$ in the streaming model, where we only have one-time, sequential access to the input intervals, the endpoints of the intervals lie in $\{1,...,n \}$, and the amount of the memory is constrained. For intervals of different sizes, we provide an algorithm in the data stream model that computes an estimate $\hat\alpha$ of $\alpha(\mathbb{I})$ that, with probability at least $2/3$, satisfies $\tfrac 12(1-\varepsilon) \alpha(\mathbb{I}) \le \hat\alpha \le \alpha(\mathbb{I})$. For same-length intervals, we provide another algorithm in the data stream model that computes an estimate $\hat\alpha$ of $\alpha(\mathbb{I})$ that, with probability at least $2/3$, satisfies $\tfrac 23(1-\varepsilon) \alpha(\mathbb{I}) \le \hat\alpha \le \alpha(\mathbb{I})$. The space used by our algorithms is bounded by a polynomial in $\varepsilon^{-1}$ and $\log n$. We also show that no better estimations can be achieved using $o(n)$ bits of storage. We also develop new, approximate solutions to the interval selection problem, where we want to report a feasible solution, that use $O(\alpha(\mathbb{I}))$ space. Our algorithms for the interval selection problem match the optimal results by Emek, Halld{\'o}rsson and Ros{\'e}n [Space-Constrained Interval Selection, ICALP 2012], but are much simpler.Comment: Minor correction

Quantitative and qualitative analysis of editor behavior through potentially coercive citations

© 2017 by the authors. How much is the h-index of an editor of a well-ranked journal improved due to citations which occur after his/her appointment? Scientific recognition within academia is widely measured nowadays by the number of citations or h-index. Our dataset is based on a sample of four editors from a well-ranked journal (impact factor, IF, greater than 2). The target group consists of two editors who seem to benefit by their position through an increased citation number (and subsequently h-index) within the journal. The total amount of citations for the target group is greater than 600. The control group is formed by another set of two editors from the same journal whose relations between their positions and their citation records remain neutral. The total amount of citations for the control group is more than 1200. The timespan for which the citations' pattern has been studied is 1975-2015. Previous coercive citations for a journal's benefit (an increase of its IF) has been indicated. To the best of our knowledge, this is a pioneering work on coercive citations for personal (editors') benefit. Editorial teams should be aware about this type of potentially unethical behavior and act accordingly

Biochemical substitution of fungal xylanases for prebleaching of hardwood kraft pulp

Xylanase enzymes of three fungi, Aspergillus indicus, A. flavus and A. niveus, were purified and characterized. The enzymes are used in the pretreatment of Hardwood kraft pulp prior to conventional alkali extraction and conventional chlorine extraction sequence (EDED process) normally used forbleaching of pulp. In the enzyme pretreated pulp when subjected to alkali extraction process the kappa number was reduced to a maximum of 5.0, 6.2 and 6.8 from 18.60 and the brightness was increased to a maximum of 43.12, 42.20 and 45.19 ISO units, respectively, from 19.83 by xylanases of A. indicus, A. flavus and A. niveus. Whereas, in the enzyme pretreated pulp, when subjected to EDED process, the maximum reduction in kappa number of 6.7, 7.2 and 7.1 and a maximum increase in brightness of 41.28, 41.06 and 41.07 ISO units, respectively, were observed in case of A. indicus, A. flavus and A. niveu

Investigation of microvesicle uptake by mouse lung-marginated monocytes in vitro.

Extracellular microvesicles (MVs) are released into the circulation in large numbers during acute systemic inflammation, yet little is known of their intravascular cell/tissue-specific interactions under these conditions. We recently described a dramatic increase in the uptake of intravenously injected MVs by monocytes marginated within the pulmonary vasculature, in a mouse model of low-dose lipopolysaccharide-induced systemic inflammation. To investigate the mechanisms of enhanced MV uptake by monocytes, we developed an in vitro model using in vivo derived monocytes. Although mouse blood is a convenient source, monocyte numbers are too low for in vitro experimentation. In contrast, differentiated bone marrow monocytes are abundant, but they are rapidly mobilized during systemic inflammation, and thus no longer available. Instead, we developed a protocol using marginated monocytes from the pulmonary vasculature as an anatomically relevant and abundant source. Mice are sacrificed by terminal anesthesia, the lungs inflated and perfused via the pulmonary artery. Perfusate cell populations are evaluated by flow cytometry, combined with in vitro generated fluorescently labelled MVs, and incubated in suspension for up to one hour. Washed cells are analyzed by flow cytometry to quantify MV uptake and confocal microscopy to localize MVs within cells (O'Dea et al., 2020). Using this perfusion-based method, substantial numbers of marginated pulmonary vascular monocytes are recovered, allowing multiple in vitro tests to be performed from a single mouse donor. As MV uptake profiles were comparable to those observed in vivo, this method is suitable for physiologically relevant high throughput mechanistic studies on mouse monocytes under in vitro conditions. Graphic abstract: Figure 1. Schematic of lung perfusate cell harvest and co-incubation with in vitro generated MVs. Created with BioRender.com

Isolation, identification and screening of potential xylanolytic enzyme from litter degrading fungi

Consortia of litter degrading fungal species were developed from different baiting substrates collected in and around Western ghat forest ecosystem, Coimbatore, Tamilnadu, India. Fifty-three litter degradingfungal species were isolated by nylon litterbag technique. The production of endo-b-1,4-xylanase (1,4-b-D-xylan xylanohydrolase, E.C. 3.2.1.8), b-D-xylosidase (1,4-b-xylan xylanohydrolase, E.C. 3.2.1.37) and protease was studied using oat spelt xylan as carbon source. Results showed that all fifty-three fungal species isolated from various litter samples produced fairly good xylanolytic enzyme activity. The xylanase and b-D-xylosidase activity ranges from 4.41 to 132.20 U and 48.72 to 1510.32 U, respectively. Growth was determined in terms of mycelial dry weight, which ranged between 0.209 and 1.047 mg/ml. The protease enzyme activity was from 19.7 to 60.8 U. This is the first report concerning xylanolyticenzyme production by the litter degrading fungi, isolated from litter samples