130,425 research outputs found
Mid-trimester amniocentesis and antibiotic prophylaxis.
No full textPrenat Diagn. 2007 Oct;27(10):956-9.
Mid-trimester amniocentesis and antibiotic prophylaxis.
Gramellini D, Fieni S, Casilla G, Raboni S, Nardelli GB.
SourceDepartment of Gynecology, Obstetrics and Neonatology, University of Parma, Parma, Italy. [email protected]
Abstract
OBJECTIVES AND METHODS: Assuming that the rate of fetal loss after amniocentesis may be reduced in patients receiving antibiotic prophylaxis, we conducted a retrospective study on untreated versus treated patients receiving prophylactic antibiotics (amoxicillin/clavulanic-acid or azithromycin) and evaluated the fetal loss rate within the 22nd week of gestation, also with respect to the risk of spontaneous abortion, both preexisting and related to mid-trimester amniocentesis.
RESULTS: Spontaneous abortion occurred in 22 cases out of 1744 (1.26%). The incidence of spontaneous abortion was 1.3% among patients treated with antibiotic prophylaxis and 1.2% among untreated patients. Between patients with risk factors that predated amniocentesis, the spontaneous fetal loss rate was 9.2% in untreated patients versus 2.3% in patients treated (p = 0.10). In patients with procedure-related risk factors at amniocentesis, the spontaneous abortion rate was, respectively, 2.2 and 1.2% (p = 0.72).
CONCLUSION: Our data demonstrate that antibiotic prophylaxis does not reduce the risk of spontaneous abortion within the 22nd week of gestation. Compared with untreated patients, patients treated with amoxicillin showed the lower fetal loss rate (1.16 vs 0.31%), but the difference was not statistically significant (odds ratio (OR) = 3.68, p = 0.32). The same was true for patients with preexisting risks (OR = 4.25, p = 0.10)
Pilot experimentation with complete mixing anoxic reactors to improve sewage denitrification in treatment plants in small communities
No full textThis paper reports the results of two sewage treatment tests in a community of 15,000 inhabitants. The sewage treatment plant is subject to strong fluctuations in load (BOD5, COD, TKN), and in particular in the BOD5/TKN ratio. These fluctuations adversely affect the biological denitrification, as demonstrated by many pilot and real-scale plants. The plants we tested were subjected to two treatment types: anoxic-aerobic and simultaneous denitrification. Both processes are designed for complete mixing conditions in the reactors in order to level the fluctuations in the load and thus improve the denitrification efficiency. The results prove that an average denitrification efficiency of up to 80% can be achieved with the sludge loading close to 0.1 kg BOD5 (d∙kgMLVSS)−1. The effect of the sludge loading and dissolved oxygen on the denitrification efficiency is highlighted
A modified biotrickling filter for nitrification-denitrification in the treatment of airborne ammonia
No full textA conventional biotrickling filter for airborne ammonia nitrification has been modified, by converting the liquid sump into a biological denitrifying reactor. The biotricking filter achieves an ammonia removal efficiency of 92.4% av., with an EBRT (Empty Bed Retention Time) = 36 s and an av. ammonia concentration of 54.7 mg Nm-3 in the raw air stream. The denitrification reactor converts ammonia into inert gas N2, in addition to other important advantages connected to the alkaline character of the biochemical pathway of the denitrifying bacteria. Firstly the trickling water crossing the denitrification reactor, underwent a notable increase in pH (from an average pH=7.3 to 8.0) which prevented the acidic inhibition of the nitrifying bacteria due to the build-up of nitric and nitrous acids. Secondly, the increase in pH created the ideal conditions for the autotrophic nitrifying bacteria. Our tests proved that an ammonia removal efficiency of above 90% can be achieved with an EBRT greater than 30 s and an ammonia volumetric load lower than 200 g ammonia d-1 m3. The results of the biofilm observation using a scanning confocal laser microscope, are reported together with the identification of degrading bacteria genera in the biotrickling filter. Overall, the efficiency of the plant and its excellent operational stability highlight the effectiveness of the synergistic action between the denitrification reactor and the biotrickling filter in removing airborne ammonia.A conventional biotrickling filter for airborne ammonia nitrification has been modified, by converting the liquid sump into a biological denitrifying reactor. The biotrickling filter achieves an average ammonia removal efficiency of 92.4 %, with an empty bed retention time (EBRT) equal to 36 s and an average ammonia concentration of 54.7 mg Nm(-3) in the raw air stream. The denitrification reactor converts ammonia into inert gas N-2, in addition to other important advantages connected to the alkaline character of the biochemical pathway of the denitrifying bacteria. Firstly, the trickling water crossing the denitrification reactor underwent a notable pH increase from 7.3 to 8.0 which prevented the acidic inhibition of the nitrifying bacteria due to the buildup of nitric and nitrous acids. Secondly, the pH increase created the ideal conditions for the autotrophic nitrifying bacteria. The tests proved that an ammonia removal efficiency of above 90 % can be achieved with an EBRT greater than 30 s and a volumetric load lower than 200 g NH3 m(-3) day(-1). The results of the biofilm observation by using a scanning confocal laser microscope are reported together with the identification of degrading bacteria genera in the biotrickling filter. The efficiency of the plant and its excellent operational stability highlight the effectiveness of the synergistic action between the denitrification reactor and the biotrickling filter in removing airborne ammonia
Calculating specific denitrification rates in pre-denitrification by assessing the influence of dissolved oxygen, sludge loading and mixed-liquor recycle
No full textThis article presents the results of an experimental study on the correlation among the specific denitrification rate (SNDR), the dissolved oxygen concentration (DO), the F:M ratio (F:M) and the mixed-liquor (ML) recycle in the pre-denitrification reactors fed by domestic sewage. The experimental curves reveal a 28.8-32.0% reduction in the SDNR at 20 °C (SDNR20°C) with DO equal to 0.1 mgO2 L-1 and F:M in the range 0.2-0.4 kgBOD5 kgMLVSS-1 d-1 . The SNDR reduction increases to 50.0-55.9% with DO = 0.3 mgO2 L-1. A mathematical correlation of these results and an equation for calculating SDNR20°C as function of the F:M as well as the average DO and BOD5 in the total flow-rate fed in the denitrification stage are proposed. The conducted experience gives useful suggestions for practical usage, in particular regarding the denitrification reactor design, and represents a good starting point for future applications with the aim to optimize the biological process in domestic sewage treatment plants
Experimental treatment of a refinery waste air stream, for BTEX removal, by water scrubbing and biotrickling on a bed of Mitilus edulis shells
No full textThe paper presents the results of a two-stage pilot plant for the removal of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) from a waste air stream of a refinery wastewater treatment plant (WWTP). The pilot plant consisted of a water scrubber followed by a biotrickling filter. The exhausted air was drawn from the main works of the WWTP in order to prevent the free migration to the atmosphere of these volatile hazardous contaminants. Concentrations were detected at average values of 12.4 mg Nm-3 for benzene, 11.1 mg Nm-3 for toluene, 2.7 mg Nm-3 for ethylbenzene and 9.5 mg Nm-3 for xylene, with considerable fluctuation mainly for benzene and toluene (peak concentrations of 56.8 mg Nm-3 and 55.0 mg Nm-3, respectively). The two treatment stages proved to play an effective complementary tasks: the water scrubber demonstrated the ability to remove the concentration peaks, while the biotrickling filter was effective as a polishing stage. The overall average removal efficiency achieved was 94.8% while the scrubber and biotrickling filter elimination capacity were 37.8 and 15.6 gBTEX d-1 m-3, respectively. This result has led to outlet average concentrations of 1.02, 0.25, 0.32 and 0.26 mg Nm-3 for benzene, toluene, ethylbenzene and xylene, respectively. The paper also compares these final concentrations with toxic and odour threshold concentrations
Full scale treatment of ASR wastes in a modified rotary kiln
No full textA plant, designed for the thermo-valorisation of tyres, was specifically modified in order to treat Automobile Shredder Residue (ASR). Results from two full-scale combustion experiments, carried out on large ASR feeding lots (thousands of tons) indicate the proposed technology as a potential route to help the fulfilling of impending 95% reuse and recovery target set by the End of life Vehicle (ELV) Directive (January 2015). The paper describes the main operational troubleshot occurred during the first experiment (emissions at the stack out of regulatory limits and problems of clogging on the conveyer belt) and the consequent upgrading solutions (pre-treatment, introduction of waste double low-flow screw feeder and a cyclone prior to the main fan, modification of rotatory kiln inlet) adopted to allow, during the second long-term experiment, a continuous basis operation of the plant in full compliance with the discharge limit to the atmosphere. Characterization of both ASR and combustion residues allowed to quantify a 18% of combustion residues as not dangerous waste while only the 2% as hazardous one. A pre-treatment for the reduction of fines in the ASR was recommended in order to achieve the required energy recovery efficiency
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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