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1.  An integrated low phase noise radiation-pressure-driven optomechanical oscillator chipset 
Scientific Reports  2014;4:6842.
High-quality frequency references are the cornerstones in position, navigation and timing applications of both scientific and commercial domains. Optomechanical oscillators, with direct coupling to continuous-wave light and non-material-limited f × Q product, are long regarded as a potential platform for frequency reference in radio-frequency-photonic architectures. However, one major challenge is the compatibility with standard CMOS fabrication processes while maintaining optomechanical high quality performance. Here we demonstrate the monolithic integration of photonic crystal optomechanical oscillators and on-chip high speed Ge detectors based on the silicon CMOS platform. With the generation of both high harmonics (up to 59th order) and subharmonics (down to 1/4), our chipset provides multiple frequency tones for applications in both frequency multipliers and dividers. The phase noise is measured down to −125 dBc/Hz at 10 kHz offset at ~400 μW dropped-in powers, one of the lowest noise optomechanical oscillators to date and in room-temperature and atmospheric non-vacuum operating conditions. These characteristics enable optomechanical oscillators as a frequency reference platform for radio-frequency-photonic information processing.
PMCID: PMC4213771  PMID: 25354711
2.  Is routine nasoendoscopy warranted in epistaxis patients after removal of nasal packing? 
Allergy & Rhinology  2011;2(1):12-15.
Fiberoptic nasoendoscopy (FNE) is a powerful investigative tool in ear, nose, and throat practice in which its use in the management of epistaxis is varied among clinicians. The practice of assessing the nasal cavity after removal of nasal packs is common but its usefulness has not been evaluated. Therefore, we assessed the benefits of routine FNE after removal of nasal packs in epistaxis patients. Our study was performed retrospectively involving 62 adult patients admitted over a 6-month period between 2005 and 2006. Data regarding the emergent management of epistaxis cases on presentation, the use of FNE, and the final diagnosis and outcome of each patient were specifically investigated during the study. Anterior rhinoscopy was performed in 27 patients at initial presentation, of whom 45% (10/27) had anterior bleeding points identified. FNE examination after removal of nasal packs in eight patients yielded evidence of a posterior bleeding point in only one case (12.5%). Of those patients in whom anterior rhinoscopy revealed no anterior bleeding point at presentation (17/27), 12 patients went on to have FNE after removal of their nasal packs, and of these, 33% (4/12) of patients were found to have a posterior bleeding vessel. Overall, FNE was performed in 24 patients, of whom only 1 (1/24) had an active posterior bleeding vessel needing nasal repacking. Four patients (4/24) had prominent posterior vessels that required no intervention, 1 patient (1/24) had new pathology identified, and in the remaining 18 cases (18/24), FNE yielded no additional information to modify management. The routine performance of FNE in all epistaxis patients after pack removal does not appear to convey any additional benefit. We advocate the use of FNE when anterior bleeding has been excluded or bleeding is persistent and that careful nasal examination by anterior rhinoscopy should be the cornerstone of assessment.
PMCID: PMC3390123  PMID: 22852109
Epistaxis; fibreoptic nasendoscopy
3.  Does chronic opioid use really reduce pain? 
Canadian Family Physician  2006;52(12):1540.
PMCID: PMC1783749  PMID: 17279231
4.  Retrospective audit of different antenatal screening policies for Down's syndrome in eight district general hospitals in one health region 
BMJ : British Medical Journal  2002;325(7354):15.
To compare the effectiveness of different screening policies for the antenatal detection of Down's syndrome.
Retrospective six year survey.
Maternity units of eight districts.
Women who completed their pregnancies between 1 January 1994 and 31 December 1999 (155 501 deliveries).
Main outcome measures
Cases of Down's syndrome identified before 24 weeks' gestation.
335 cases of Down's syndrome were identified, 323 in continuing pregnancies or liveborn children. Of these, 171 were identified antenatally. Seven different screening policies were used, in three principal groups: serum screening offered to all mothers, maternal age with serum screening or nuchal translucency available to limited groups, and maternal age combined with anomaly scans. The districts that used serum screening detected 57%, those using maternal age plus serum or nuchal translucency screening 52%, and those using a maternal age of ⩾35 and anomaly scans detected 54%. The least successful district, which offered amniocentesis only to women aged over 37 years, detected only 31%. If amniocentesis had been offered from 35 years, as in all other districts, the detection rate would have risen to 54%. Across the region 15% (range 12-20%) of pregnant women were 35 years or more at delivery, and 58% (33-69%) of infants with Down's syndrome were born to women in this age range.
Current additional serum or nuchal translucency screening techniques for antenatal detection of Down's syndrome are less advantageous than previously supposed. More pregnant women were aged over 35 than has been presumed in statistical models used in demonstration projects of serum screening and, as a result, the proportion of affected fetuses in this age group is much greater than predicted.
What is already known on this topicSerum screening for Down's syndrome has been presumed to be more effective than screening by maternal ageThere have been no controlled studies comparing serum screening with screening by maternal age, and its greater efficacy has been presumed from mathematical modelling, which assumed that only 5% of pregnant women were aged over 35 yearsThe modelling predicted that only 20-30% of cases of Down's syndrome would arise in women aged over 35 and made no allowance for the effects of routine anomaly scanningWhat this study adds15% of pregnant women were aged over 35 years, more than double the 5-7% presumed in statistical models of screening58% of babies with Down's syndrome were born to women aged 35 years or moreSerum screening and nuchal scanning did not achieve significantly higher antenatal detection rates of Down's syndrome than the use of maternal age and routine anomaly scanning
PMCID: PMC116665  PMID: 12098722
5.  Six year survey of screening for Down's syndrome by maternal age and mid-trimester ultrasound scans 
BMJ : British Medical Journal  2000;320(7235):606-610.
To assess the effectiveness of antenatal screening for Down's syndrome by maternal age and routine mid-pregnancy ultrasound scanning.
Retrospective six year survey.
Maternity units of a district general hospital.
Pregnant women booked for delivery in hospital between 1 January 1993 and 31 December 1998.
Main outcome measures
All cases of Down's syndrome occurring in district identified from regional congenital anomaly register and cytogenetic laboratory records. Women's case notes were examined to identify indication for karyotyping, gestation at diagnosis, and outcome of pregnancy.
31 259 deliveries occurred during study period, and 57 cases of Down's syndrome were identified, four in failed pregnancies and 53 in ongoing pregnancies or in neonates. The analysis was confined to ongoing pregnancies or liveborn children. Invasive antenatal tests were performed in 6.6% (2053/31 259), and 68% (95% confidence interval 56% to 80%) of cases of Down's syndrome were detected antenatally, giving a positive predictive value of 1.8%. There were 17 undetected cases, and in seven of these the women had declined an offer of invasive testing. In women aged less than 35 years the detection rate was 53% (30% to 76%). Most of the cases detected in younger women followed identification of ultrasound anomalies.
The overall detection rate was considerably higher than assumed in demonstration projects for serum screening. As a result, the benefits of serum screening are much less than supposed. Before any new methods to identify Down's syndrome are introduced, such as nuchal translucency or first trimester serum screening, the techniques should be tested in properly controlled trials.
Key messagesSerum screening for Down's syndrome has never been compared with screening by maternal age in a controlled trialThis study examined the effectiveness of screening by maternal age in combination with mid-trimester ultrasound scanningThe overall detection rate was 68%, considerably more effective than assumed in demonstration projects of serum screeningThe benefits of serum screening, compared with screening by maternal age in conjunction with routine fetal anomaly scanning, may be much less than supposedA higher standard of evidence should be demanded before proposed new screening methods are adopted
PMCID: PMC27301  PMID: 10698877

Results 1-8 (8)