Simple models of the chemical field around swimming plankton

International audienceThe chemical field around swimming plankton depends on the swimming style and speed of the organism and the processes affecting uptake or exudation of chemicals by the organism. Here we present a simple model for the flow field around a neutrally buoyant self-propelled organism at low Reynolds number, and numerically calculate the chemical field around the organism. We show how the concentration field close to the organism and the mass transfer rates vary with swimming speed and style for Dirichlet (diffusion limited transport) boundary conditions. We calculate how the length of the chemical wake, defined as being the distance at which the chemical field drops to 10% of the surface concentration of the organism when stationary, varies with swimming speed and style for both Dirichlet and Neumann (production limited) boundary conditions. For Dirichlet boundary conditions, the length of the chemical wake increases with increasing swimming speed, and the self-propelled organism displays a significantly longer wake than the towed-body model. For the Neumann boundary conditions the converse is true; because swimming enhances the transport of the chemical away from the organism, the surface concentration of chemical is reduced and thus the wake length is reduced

Association of Inosine and Cytidine

A rigorous theory for the analysis of an associating system involving two different monomer units, which may also undergo self-association, has been developed. In the present paper the application of the theory to actual data is demonstrated for the first time. The model system chosen is the interaction of inosine with cytidine, both of which self-associate strongly. Application of the theory indicates that inosine associates with cytidine and that the association constant is of a similar order of magnitude to that for the self-association of the monomers

Pattern Based Mining For Relevant Document Extraction

This paper presents efficient mining algorithm for discovering patterns from text collection and search for useful and interesting patterns. For extracting useful information we used pattern based model containing frequent sequential patterns and pruned the meaningless patterns. Here an innovative and effective technique is used for pattern discovery which includes SPM & FP growth algorithms for pattern mining and applies the processes of pattern deploying, pattern evolving, to improve the effectiveness of using and updating discovered patterns for finding relevant and interesting information

A study of comparing single dose granisetron with combination of granisetron with dexamethasone in preventing postoperative nausea vomiting in laparoscopic cholecystectomies

Background: Postoperative nausea and vomiting (PONV) remains a vexing problem despite of advances in anaesthesia care. PONV is distressing adverse effect after anaesthesia and surgery, resulting in significant morbidity due to acute discomfort associated with emetic symptoms and longer stays in the recovery room or unexpected hospital admission in ambulatory settings.Methods: A prospective, randomized, double blind comparative study was conducted to compare the efficacy and adverse effects of injection granisetron 40µg/kg as a single dose and injection granisetron in two different doses (20µg/kg and 40µg/kg) in combination with dexamethasone 160µg/kg for prevention of postoperative nausea and vomiting in patients undergoing general anaesthesia for elective laparoscopic cholecystectomy.Results: Nausea and vomiting were observed postoperatively at 0, 1, 2, 4, 8, and 24 consecutive hours after patient responded to verbal commands. Intensity of nausea graded verbally with an eleven point score (0-10) with those patients who scored their nausea as zero were termed nausea free, and 10 being most severe. Nausea scores when patient complains of nausea & if patient demand rescue antiemetic for nausea was noted down along with adverse effects if any. The data was analysed by ANOVA followed by unpaired‘t’ test, Chi-square/Fischer exact test or Kruskal Wallis Test.Conclusions: Granisetron as a single agent in dose 40µg/kg is effective as prophylactic antiemetic in preventing PONV in laparoscopic cholecystectomy whereas addition of dexamethasone 160µg/kg to granisetron significantly increases antiemetic efficacy of the granisetron in both the doses i.e. 20µg/kg and 40µg/kg without increasing any side effect. Granisetron 40µg//kg+injection dexamethasone 160µg/kg is best for antiemetic prophylaxis in highly emetogenic surgeries like laparoscopic cholecystectomy.  Granisetron 20µg/kg + injection dexamethasone can be cost effective alternative for routine antiemetic prophylaxis compared to granisetron 40µg//kg and granisetron 40µg//kg+ injection dexamethasone for all patients undergoing laparoscopic cholecystectomy.

Year-long monitoring of physico-chemical and biological variables provide a comparative baseline of coral reef functioning in the central Red Sea.

Research reported in this publication was supported by funding to CRV from King Abdullah University of Science and Technology (KAUST)

What are the benefits of preemptive versus non-preemptive kidney transplantation? A systematic review and meta-analysis

Opting for a preemptive kidney transplant (PKT) can help avoid costs and morbidity associated with dialysis. However, while multiple studies have shown clinical benefits of PKT, other studies have not demonstrated this, leading to controversy in the literature regarding the exact benefits of PKT. Therefore, this study aimed to determine the clinical outcomes of PKT versus non-preemptive kidney transplantation (nPKT) in adult patients. Multiple databases were searched up to May 4, 2022. Independent reviewers selected studies for inclusion and extracted relevant data. Risk of bias was assessed using the Downs and Black checklist. Eighty-seven studies including 859,715 adult kidney transplant patients were included the review. The risk of patient death (relative risk [95% confidence interval] 0.74 [0.60–0.91]) was significantly lower in PKT versus nPKT patients for living donor (LD) transplants, whereas the risk of overall graft loss was significantly lower in PKT compared to nPKT patients for both LD (0.72 [0.62–0.83]) as well as deceased donor (DD) transplants (0.80 [0.69–0.92]). The evidence suggests that LD PKT patients have a lower risk of patient death and graft loss compared to nPKT patients, and DD PKT patients have a lower risk of graft loss than nPKT patients.</p

Effect of Pressure, Environment Temperature, Jet Velocity and Nitrogen Dilution on the Liftoff Characteristics of a N2-in-H2 Jet Flame in a Vitiated Co-flow

The CO2 emission prevention advantage of generating power with high hydrogen content fuels using gas turbines motivates an improved understanding of the ignition behavior of hydrogen in premixed and partially premixed environments. Hydrogen rich fueled flame stability is sensitive to operating conditions, including environment pressure, temperature, and jet velocity. Furthermore, when premixed or partially premixed operation is needed for nitric oxide emissions reduction, a diluent, such as nitrogen, is often added in allowing fuel/air mixing prior to combustion. Thus, the concentration of the diluent added is an additional independent variable on which flame stability dependence is needed. The focus of this research is on characterizing the dependence of hydrogen jet flame stability on environment temperature, pressure, jet velocity and diluent concentration by determining the dependence of the liftoff height of lifted flames on these 4 independent parameters. Nitrogen is used as the diluent due to its availability and effectiveness in promoting liftoff. A correlation modeling the liftoff height dependence on operating conditions is developed which emphasizes the factors that bear the greatest impact on ignition behavior