Effect of Injector Exit Geometry on Atomization of a Liquid-Liquid Double Swirl Coaxial Injector using Non-Invasive Laser, Optical, and X-ray Techniques

The spray characteristics of a liquid-liquid double swirl coaxial injector were studied using non-invasive optical, laser, and X-ray diagnostics. Phase Doppler interferometry was used to characterize droplet statistics and non-dimensional droplet parameters over a range of inlet conditions and for various fluids allowing for a study on the role of fluid properties on atomization. Based on the atomization statistics and observed trends from high-speed images, a description of breakup regimes over a range of Reynolds and Weber numbers was created. Next, X-ray computed tomography scans revealed that the spray cone was distinctively non-uniform and comprised of several pockets of increased mass concentration which varied with injection pressure. Finally, a parametric study of injector exit geometry demonstrated that spray breakup time, breakup type, and sheet stability could be controlled with exit geometry. Implications for these data on injector stability and atomization efficiency are discussed considering the desired performance characteristics of liquid-liquid rocket injectors

Theory of Electric Field-Induced Photoluminescence Quenching in Disordered Molecular Solids

The dynamics of excitons in disordered molecular solids is studied theoretically, taking into account migration between different sites, recombination, and dissociation into free charge carriers in the presence of an electric field. The theory is applied to interpret the results of electric field-induced photoluminescence (PL) quenching experiments on molecularly doped polymers by Deussen et al. [Chem. Phys. 207, 147 (1996)]. Using an intermolecular dissociation mechanism, the dependence of the PL quenching on the electric field strength and the dopant concentration, and the time evolution of the transient PL quenching can be well described. The results constitute additional proof of the distinct exciton dissociation mechanisms in conjugated polymer blends and molecularly doped polymers.Comment: 4 pages RevTeX, 3 Postscript figure

Effects of gastroprotectant drugs for the prevention and treatment of peptic ulcer disease and its complications: a meta-analysis of randomised trials

Background: Gastroprotectant drugs are used for the prevention and treatment of peptic ulcer disease and might reduce its associated complications, but reliable estimates of the effects of gastroprotectants in different clinical settings are scarce. We aimed to examine the effects of proton-pump inhibitors (PPIs), prostaglandin analogues, and histamine-2 receptor antagonists (H2RAs) in different clinical circumstances by doing meta-analyses of tabular data from all relevant unconfounded randomised trials of gastroprotectant drugs. Background: Gastroprotectant drugs are used for the prevention and treatment of peptic ulcer disease and might reduce its associated complications, but reliable estimates of the effects of gastroprotectants in different clinical settings are scarce. We aimed to examine the effects of proton-pump inhibitors (PPIs), prostaglandin analogues, and histamine-2 receptor antagonists (H2RAs) in different clinical circumstances by doing meta-analyses of tabular data from all relevant unconfounded randomised trials of gastroprotectant drugs. Methods: We searched MEDLINE and Embase from Jan 1, 1950, to Dec 31, 2015, to identify unconfounded, randomised trials of a gastroprotectant drug (defined as a PPI, prostaglandin analogue, or H2RA) versus control, or versus another gastroprotectant. Two independent researchers reviewed the search results and extracted the prespecified outcomes and key characteristics for each trial. We did meta-analyses of the effects of gastroprotectant drugs on ulcer development, bleeding, and mortality overall, according to the class of gastroprotectant, and according to the individual drug within a gastroprotectant class. Findings: We identified comparisons of gastroprotectant versus control in 849 trials (142 485 participants): 580 prevention trials (110 626 participants), 233 healing trials (24 033 participants), and 36 trials for the treatment of acute upper gastrointestinal bleeding (7826 participants). Comparisons of one gastroprotectant drug versus another were available in 345 trials (64 905 participants), comprising 160 prevention trials (32 959 participants), 167 healing trials (28 306 participants), and 18 trials for treatment of acute upper gastrointestinal bleeding (3640 participants). The median number of patients in each trial was 78 (IQR 44·0–210·5) and the median duration was 1·4 months (0·9–2·8). In prevention trials, gastroprotectant drugs reduced development of endoscopic ulcers (odds ratio [OR] 0·27, 95% CI 0·25–0·29; p<0·0001), symptomatic ulcers (0·25, 0·22–0·29; p<0·0001), and upper gastrointestinal bleeding (0·40, 0·32–0·50; p<0·0001), but did not significantly reduce mortality (0·85, 0·69–1·04; p=0·11). Larger proportional reductions in upper gastrointestinal bleeding were observed for PPIs than for other gastroprotectant drugs (PPIs 0·21, 99% CI 0·12–0·36; prostaglandin analogues 0·63, 0·35–1·12; H2RAs 0·49, 0·30–0·80; phet=0·0005). Gastroprotectant drugs were effective in preventing bleeding irrespective of the use of non-steroidal anti-inflammatory drugs (phet=0·56). In healing trials, gastroprotectants increased endoscopic ulcer healing (3·49, 95% CI 3·28–3·72; p<0·0001), with PPIs more effective (5·22, 99% CI 4·00–6·80) than prostaglandin analogues (2·27, 1·91–2·70) and H2RAs (3·80, 3·44–4·20; phet<0·0001). In trials among patients with acute bleeding, gastroprotectants reduced further bleeding (OR 0·68, 95% CI 0·60–0·78; p<0·0001), blood transfusion (0·75, 0·65–0·88; p=0·0003), further endoscopic intervention (0·56, 0·45–0·70; p<0·0001), and surgery (0·72, 0·61–0·84; p<0·0001), but did not significantly reduce mortality (OR 0·90, 0·72–1·11; p=0·31). PPIs had larger protective effects than did H2RAs for further bleeding (phet=0·0107) and blood transfusion (phet=0·0130). Interpretation: Gastroprotectants, in particular PPIs, reduce the risk of peptic ulcer disease and its complications and promote healing of peptic ulcers in a wide range of clinical circumstances. However, this meta-analysis might have overestimated the benefits owing to small study bias

Three-body non-additive forces between spin-polarized alkali atoms

Three-body non-additive forces in systems of three spin-polarized alkali atoms (Li, Na, K, Rb and Cs) are investigated using high-level ab initio calculations. The non-additive forces are found to be large, especially near the equilateral equilibrium geometries. For Li, they increase the three-atom potential well depth by a factor of 4 and reduce the equilibrium interatomic distance by 0.9 A. The non-additive forces originate principally from chemical bonding arising from sp mixing effects.Comment: 4 pages, 3 figures (in 5 files

Red Oak Seedlings as Indicators of Deer Browse Pressure: Gauging the Outcome of Different White-Tailed Deer Management Approaches

After decades of high deer populations, North American forests have lost much of their previous biodiversity. Any landscape‐level recovery requires substantial reduc‐ tions in deer herds, but modern societies and wildlife management agencies appear unable to devise appropriate solutions to this chronic ecological and human health crisis. We evaluated the effectiveness of fertility control and hunting in reducing deer impacts at Cornell University. We estimated spring deer populations and planted Quercus rubra seedlings to assess deer browse pressure, rodent attack, and other factors compromising seedling performance. Oak seedlings protected in cages grew well, but deer annually browsed ≥60% of unprotected seedlings. Despite female ster‐ ilization rates of \u3e90%, the deer population remained stable. Neither sterilization nor recreational hunting reduced deer browse rates and neither appears able to achieve reductions in deer populations or their impacts. We eliminated deer sterilization and recreational hunting in a core management area in favor of allowing volunteer arch‐ ers to shoot deer over bait, including at night. This resulted in a substantial reduction in the deer population and a linear decline in browse rates as a function of spring deer abundance. Public trust stewardship of North American landscapes will require a fundamental overhaul in deer management to provide for a brighter future, and oak seedlings may be a promising metric to assess success. These changes will re‐ quire intense public debate and may require new approaches such as regulated com‐ mercial hunting, natural dispersal, or intentional release of important deer predators (e.g., wolves and mountain lions). Such drastic changes in deer management will be highly controversial, and at present, likely difficult to implement in North America. However, the future of our forest ecosystems and their associated biodiversity will depend on evidence to guide change in landscape management and stewardship

Using heterozygosity-fitness correlations to study inbreeding depression in an isolated population of white-tailed deer founded by few individuals

A heterozygosity-fitness correlations (HFCs) may reflect inbreeding depression, but the extent to which they do so is debated. HFCs are particularly likely to occur after demographic disturbances such as population bottleneck or admixture. We here study HFC in an introduced and isolated ungulate population of white-tailed deer Odocoileus virginianus in Finland founded in 1934 by four individuals. A total of 4221-year-old white-tailed deer were collected in the 2012 hunting season in southern Finland and genotyped for 14 microsatellite loci. We find significant identity disequilibrium as estimated by g(2). Heterozygosity was positively associated with size- and age-corrected body mass, but not with jaw size or (in males) antler score. Because of the relatively high identity disequilibrium, heterozygosity of the marker panel explained 51% of variation in inbreeding. Inbreeding explained approximately 4% of the variation in body mass and is thus a minor, although significant source of variation in body mass in this population. The study of HFC is attractive for game- and conservation-oriented wildlife management because it presents an affordable and readily used approach for genetic monitoring that allowing identification of fitness costs associated with genetic substructuring in what may seem like a homogeneous population.Peer reviewe

Vector-borne and other pathogens of potential relevance disseminated by relocated cats

Large populations of unowned cats constitute an animal welfare, ecological, societal and public health issue worldwide. Their relocation and homing are currently carried out in many parts of the world with the intention of relieving suffering and social problems, while contributing to ethical and humane population control in these cat populations. An understanding of an individual cat’s lifestyle and disease status by veterinary team professionals and those working with cat charities can help to prevent severe cat stress and the spread of feline pathogens, especially vector-borne pathogens, which can be overlooked in cats. In this article, we discuss the issue of relocation and homing of unowned cats from a global perspective. We also review zoonotic and non-zoonotic infectious agents of cats and give a list of practical recommendations for veterinary team professionals dealing with homing cats. Finally, we present a consensus statement consolidated at the 15th Symposium of the Companion Vector-Borne Diseases (CVBD) World Forum in 2020, ultimately to help veterinary team professionals understand the problem and the role they have in helping to prevent and manage vector-borne and other pathogens in relocated cats

Endosomal NOX2 oxidase exacerbates virus pathogenicity and is a target for antiviral therapy

The imminent threat of viral epidemics and pandemics dictates a need for therapeutic approaches that target viral pathology irrespective of the infecting strain. Reactive oxygen species are ancient processes that protect plants, fungi and animals against invading pathogens including bacteria. However, in mammals reactive oxygen species production paradoxically promotes virus pathogenicity by mechanisms not yet defined. Here we identify that the primary enzymatic source of reactive oxygen species, NOX2 oxidase, is activated by single stranded RNA and DNA viruses in endocytic compartments resulting in endosomal hydrogen peroxide generation, which suppresses antiviral and humoral signaling networks via modification of a unique, highly conserved cysteine residue (Cys98) on Toll-like receptor-7. Accordingly, targeted inhibition of endosomal reactive oxygen species production abrogates influenza A virus pathogenicity. We conclude that endosomal reactive oxygen species promote fundamental molecular mechanisms of viral pathogenicity, and the specific targeting of this pathogenic process with endosomal-targeted reactive oxygen species inhibitors has implications for the treatment of viral disease.Production of reactive oxygen species is an ancient antimicrobial mechanism, but its role in antiviral defense in mammals is unclear. Here, To et al. show that virus infection activates endosomal NOX2 oxidase and restricts TLR7 signaling, and that an endosomal NOX2 inhibitor decreases viral pathogenicity.Eunice E. To, Ross Vlahos, Raymond Luong, Michelle L. Halls, Patrick C. Reading, Paul T. King, Christopher Chan, Grant R. Drummond, Christopher G. Sobey, Brad R. S. Broughton, Malcolm R. Starkey, Renee van der Sluis, Sharon R. Lewin, Steven Bozinovski, Luke A. J. O’Neill, Tim Quach, Christopher J. H. Porter, Doug A. Brooks, John J. O’Leary and Stavros Selemidi