Genetic variability and antimicrobial resistance of Ureaplasma parvum in response to maternal erythromycin treatment : a study in pregnant sheep

Background: Ureaplasmas are the most frequently isolated microorganisms from the amniotic fluid (AF) of pregnant women and can cause chronic infections that are difficult to eradicate with standard macrolide treatment. We tested the effects of erythromycin treatment on phenotypic and genotypic markers of ureaplasmal antimicrobial resistance in sheep. Method: At 50 days of gestation (d, term=145d) 12 pregnant ewes received intra-amniotic injections of U. parvum serovar 3 (erythromycin-sensitive, 2x104 colony-forming-units). At 100d ewes received: erythromycin treatment (500 mg, q3h for 4 days, IM, n=6) or no treatment (n=6). Fetuses were delivered surgically (125d) and AF and chorioamnion were collected for: culture, minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) testing; 23S rRNA sequencing; and detection of macrolide-lincosamide-streptogramin resistance (MLSr) genes. Results: MICs of erythromycin, azithromycin and roxithromycin against AF isolates were low (range = 0.06 mg/L to 1.0 mg/L); however, chorioamnion isolates demonstrated increased resistance to roxithromycin (0.13 – 5.33 mg/L). 62.5% of chorioamnion ureaplasmas formed biofilms in vitro and mutations (125 nucleotides, 29.6%) were found in the 23S rRNA gene (domain V) of chorioamnion (but not AF) ureaplasmas. MLSr genes (ermB, msrC and msrD) were detected in 100% of chorioamnion isolates and only msrD was detected in AF isolates (40%). Conclusions: 23S rRNA mutations and MLSr genes occurred independently of erythromycin treatment, suggesting that the anatomical site of infection and microenvironment may exert selective pressures on ureaplasmas that cause genetic changes and alter antimicrobial sensitivity profiles. These results have serious implications for treatment of in utero infections.

A novel real time pricing scheme for demand response in residential distribution systems

Price based technique is one way to handle increase in peak demand and deal with voltage violations in residential distribution systems. This paper proposes an improved real time pricing scheme for residential customers with demand response option. Smart meters and in-home display units are used to broadcast the price and appropriate load adjustment signals. Customers are given an opportunity to respond to the signals and adjust the loads. This scheme helps distribution companies to deal with overloading problems and voltage issues in a more efficient way. Also, variations in wholesale electricity prices are passed on to electricity customers to take collective measure to reduce network peak demand. It is ensured that both customers and utility are benefitted by this scheme.

Learning and teaching epidemiology with audience response technology

Background The learning and teaching of epidemiology is core to many public health programs. Many students find the content of epidemiology, and specifically risk of bias assessment, challenging to learn. Howbeit, learning is enhanced when knowledge is able to be acquired from an active-learning, hands-on experience. Methods The innovative use of wireless audience response technology “clickers” was incorporated into the lectures of the university’s post-graduate epidemiology units and the tailored epidemiological modules delivered for professional disciplines (e.g. optometry). Clickers were used to apply several pedagogical approaches of active learning including peer-instruction and real-world simulation. Students were also assessed for their gain in knowledge within the lecture (pre-post) and their perceptions of how the use of clickers helped them learn. The routine university-wide end of semester Insight Survey provided further information of the student’s satisfaction with the approach. Results The technology was useful in identifying deficits of knowledge of key concepts either before or after instruction. Where key concepts were re-tested post-lecture, as expected, knowledge increased significantly and provided immediate feed-back to students. Across the lecture series, typically 85% of students identified the technology helped them learn, increased their opportunity to interact with the lecturer, and recommend their use for future classes. The Insight Survey report identified 93% of respondents identified the unit in which clickers were consistently used provided good learning opportunities. Numerous student comments supported the teaching method. Conclusions Epidemiological subject matter lends itself to incorporation of audience response technology. The use of the technology to facilitate interactive voting provides an instant response and participation of everyone to enhance the classroom experience. The pedagogical approach increases students’ knowledge and increases their satisfaction with the unit.

A novel tuning method for advanced line drop compensator and its application to response coordination of distributed generation with voltage regulating devices

Nowadays, integration of small-scale electricity generators, known as Distributed Generation (DG), into distribution networks has become increasingly popular. This tendency together with the falling price of DG units has a great potential in giving the DG a better chance to participate in voltage regulation process, in parallel with other regulating devices already available in the distribution systems. The voltage control issue turns out to be a very challenging problem for distribution engineers, since existing control coordination schemes need to be reconsidered to take into account the DG operation. In this paper, a control coordination approach is proposed, which is able to utilize the ability of the DG as a voltage regulator, and at the same time minimize the interaction of DG with another DG or other active devices, such as On-load Tap Changing Transformer (OLTC). The proposed technique has been developed based on the concepts of protection principles (magnitude grading and time grading) for response coordination of DG and other regulating devices and uses Advanced Line Drop Compensators (ALDCs) for implementation. A distribution feeder with tap changing transformer and DG units has been extracted from a practical system to test the proposed control technique. The results show that the proposed method provides an effective solution for coordination of DG with another DG or voltage regulating devices and the integration of protection principles has considerably reduced the control interaction to achieve the desired voltage correction.

Audience response systems can facilitate communal course feedback

Background At Queensland University of Technology (QUT), the Bachelor of Radiation Therapy course evaluation has previously suffered from low online survey participation rates. A communal instantaneous feedback event using an audience response system (ARS) was evaluated as a potential solution to this problem. The aims of the project were to determine the extent to which this feedback event could be facilitated by ARS technology and to evaluate the impact the technology made on student satisfaction and engagement. Methods Students were invited to a timetabled session to provide feedback on individual study units and the course overall. They provided quantitative Likert-style responses to prompts for each unit and the course using an ARS as well as anonymous typed qualitative comments. Data collection was performed live so students were able to view collective class responses. This prompted further discussion and enabled a prospective action plan to be developed. To inform future ARS use, students were asked for their opinions on the feedback method. Results Despite technological difficulties, student evaluation indicated that all responders enjoyed the session and the opportunity to view the combined responses. All students felt that useful feedback was generated and that this method should be used in the future. The student attendance and response rates were high, and it was clear that the session had led to the development of some insightful qualitative feedback comments. Conclusions: An ARS contributed well to the collection of course feedback in a communal and interactive environment. Students found it enjoyable to use, and it helped to stimulate useful qualitative comments

The Behavior of Hydroxyl Units of Synthetic Goethite and its Dehydroxylated Product Hematite

The behavior of the hydroxyl units of synthetic goethite and its dehydroxylated product hematite was characterized using a combination of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) during the thermal transformation over a temperature range of 180-270 degrees C. Hematite was detected at temperatures above 200 degrees C by XRD while goethite was not observed above 230 degrees C. Five intense OH vibrations at 3212-3194, 1687-1674, 1643-1640, 888-884 and 800-798 cm(-1), and a H2O vibration at 3450-3445 cm(-1) were observed for goethite. The intensity of hydroxyl stretching and bending vibrations decreased with the extent of dehydroxylation of goethite. Infrared absorption bands clearly show the phase transformation between goethite and hematite: in particular. the migration of excess hydroxyl units from goethite to hematite. Two bands at 536-533 and 454-452 cm(-1) are the low wavenumber vibrations of Fe-O in the hematite structure. Band component analysis data of FTIR spectra support the fact that the hydroxyl units mainly affect the a plane in goethite and the equivalent c plane in hematite.