High-Q Si microresonators formed by substrate transfer on silica waveguide wafers

We report the first demonstration of Si microresonators (MRs) fabricated via substrate transfer on a silica waveguide (WG) wafer. Specifically, these Si microdisks were fabricated on a layer of Si (0.16-0.2 μm thick) that was directly-bonded on a silica waveguide wafer. We measured the throughput and drop spectrum of these microdisks when coupled to bonded silica waveguides, and observed loaded quality-factors (Qs) of ≥10(4). We modeled, in addition, the dispersion of whispering gallery modes in these microdisks to show phase-matched coupling with an incident silica waveguide or fiber-taper. Using the measured extinction ratio and loaded-Q, we evaluated, in addition, the coupling coefficient between the incident waveguide/taper and Si MR.

Abstract P3-11-11: A Comparison of Breast Cancer Treatment Rates in British Columbia, Scotland, and Western Australia, and a Comparison with Models of “Optimal” Therapy

Background: Evidence-based optimal utilization models provide estimates of optimal radiotherapy, chemotherapy and hormonal therapy utilization by stage and other clinically relevant patient sub-groups. We therefore compared predicted utilization with actual utilization of radiotherapy, hormone therapy and chemotherapy in 3 jurisdictions with population-based stage and treatment data: British Columbia, Canada; Dundee, Scotland; and Perth, Western Australia.

Methods: Previously published optimal radiotherapy, chemotherapy, and endocrine therapy treatment utilization trees for an Australian population were modified to incorporate epidemiological data from British Columbia, Dundee, and Perth, such that the optimal trees for each region reflected the casemix for each region. Frequency data on patient, tumour, and surgical factors were used to calculate optimal treatment rates for each region. Optimal rates were then compared with actual rates of surgery, radiotherapy, chemotherapy, and endocrine therapy use obtained from 2 population-based and 1 institution-based cancer registries for patients diagnosed with breast cancer between 2000 to 2004. Information on region-specific treatment guidelines was also collected.

Results: Region-specific optimal treatment utilization rates at diagnosis varied between 80% and 81% for radiotherapy (62 to 64% when patient preference is taken into account), 53% to 56% for chemotherapy, and 49% to 54% for endocrine therapy. The predicted ranges were due to local variations in demographics, and tumour stage. Actual radiotherapy utilization was 57%, 49%, and 52%; chemotherapy utilization was 32%, 24%, and 29%; and endocrine therapy utilization was 56%, 64%, and 52% for British Columbia, Dundee, and Perth, respectively. Conclusion: There are significant differences in actual treatment utilisation rates between the study populations. It is unlikely that all of this variation is due to differences in tumour characteristics alone. Actual utilization rates were lower than the calculated optimal rates for radiotherapy and chemotherapy, and higher for endocrine therapy. Differences between actual regional rates of treatment utilization were seen, and were associated with differences in mastectomy rates, and guideline recommendations for treatment use in that region. This methodology allows comparison of the treatment that occurs in a jurisdiction against what would be considered optimal based on evidence.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-11-11.

Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore

BACKGROUND

Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths.

AIMS

To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use.

METHODS

A self-administered questionnaire survey of 14,554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May-July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis.

RESULTS

A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were "useful in protecting from contracting SARS". Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW's job title, reported contact with SARS patients, area of work, and Impact Events Scale scores.

CONCLUSION

A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.

Ochratoxin A in wine and grape juice sold in Canada

Ochratoxin A (OTA) was determined in 251 samples of wines and grape juice collected over 3 years in Canada. In total, 25/84 samples of red wine, 22/96 samples of white wine, 3/46 red grape juices and 1/25 white grape juices contained OTA levels above the limit of quantitation (LOQ). Canadian wines, when compared with imported products, showed both a lower OTA occurrence, noted as positive (19 versus 48% above the limit of detection (LOD) for wines), and a lower level of OTA contamination (upper bound mean of 17.5 versus 163pg ml(-1) for wines). Wines from the USA contained no quantifiable levels of ochratoxin A. OTA was found in Canadian and US grape juice samples, with 12.9% above the LOD and an upper bound mean of 13.3pg ml(-1). It was extracted from a wine or grape juice sample by passing it through an immunoaffinity column. The sample matrix was washed off the column with water. OTA was eluted from the column with methanol and quantitatively determined by liquid chromatography using a fluorescence detector. The presence of OTA was confirmed by esterification with boron trifluoride-methanol. The LOQ of OTA was estimated as 20 pg ml(-1) in white wine (S/N 10:1) and 40 pg ml(-1) in red wine, white grape juice and red grape juice (S/N 20.1). The LOD was estimated as 4pgml(-1) for white wine and 8pgml(-1) for red wine and white and red grape juices (S/N 3:1).

Treatment of urinary tract infection with gentamicin once or three times daily

AIM

To examine the safety and efficacy of once-daily (OD) gentamicin treatment compared with conventional 8-hourly dosing (TDS) for urinary tract infection (UTI).

METHODS

This was a prospective, randomized, controlled trial of children 1 mo to 13 y of age with presumed UTI. Children were randomly assigned to OD gentamicin 5 mg kg(-1) d(-1) or TDS gentamicin 6 mg kg(-1) d(-1) divided 8 hourly. Microbiological efficacy, nephrotoxicity, ototoxicity and renal scarring were assessed at the end of treatment.

RESULTS

210 patients with presumed UTI were recruited, of whom 172 were analysable (OD 84, TDS 88). The median age was 7 mo, 50% were male and 74% (n = 127) of patients had pyelonephritis. The majority of infections were due to Escherichia coli (n = 153, 89%), of which 9 (5.2%) were bacteraemic. Comparing the two groups, there was no significant difference in age, gender, duration of fever before admission, pyuria, nitrite positivity or initial total white blood cell count. All patients had negative urine cultures after 2-3 d of treatment, demonstrating 100% microbiological efficacy. There was no difference between the two groups in terms of ototoxicity, nephrotoxicity, duration of gentamicin treatment or time to fever defervescence.

CONCLUSION

OD gentamicin is as efficacious as TDS gentamicin in the treatment of UTI in children, with no difference in ototoxicity and nephrotoxicity.