Integrated microwave photonic true-time delay with interferometric delay enhancement based on Brillouin scattering and microring resonators.

True-time delays are important building blocks in modern radio frequency systems that can be implemented using integrated microwave photonics, enabling higher carrier frequencies, improved bandwidths, and a reduction in size, weight, and power. Stimulated Brillouin scattering (SBS) offers optically-induced continuously tunable delays and is thus ideal for applications that require programmable reconfiguration but previous approaches have been limited by large SBS gain requirements. Here, we overcome this limitation by using radio-frequency interferometry to enhance the Brillouin-induced delay applied to the optical sidebands that carry RF signals, while controlling the phase of the optical carrier with integrated silicon nitride microring resonators. We report a delay tunability over 600 ps exploiting an enhancement factor of 30, over a bandwidth of 1 GHz using less than 1 dB of Brillouin gain utilizing a photonic chip architecture based on Brillouin scattering and microring resonators.

Colonoscopy quality measures: experience from the NHS Bowel Cancer Screening Programme.

OBJECTIVES: Colonoscopy is central to colorectal cancer (CRC) screening. Success of CRC screening is dependent on colonoscopy quality. The NHS Bowel Cancer Screening Programme (BCSP) offers biennial faecal occult blood (FOB) testing to 60-74 year olds and colonoscopy to those with positive FOB tests. All colonoscopists in the screening programme are required to meet predetermined standards before starting screening and are subject to ongoing quality assurance. In this study, the authors examine the quality of colonoscopy in the NHS BCSP and describe new and established measures to assess and maintain quality. DESIGN: The NHS BCSP database collects detailed data on all screening colonoscopies. Prospectively collected data from the first 3 years of the programme (August 2006 to August 2009) were analysed. Colonoscopy quality indicators (adenoma detection rate (ADR), polyp detection rate, colonoscopy withdrawal time, caecal intubation rate, rectal retroversion rate, polyp retrieval rate, mean sedation doses, patient comfort scores, bowel preparation quality and adverse event incidence) were calculated along with measures of total adenoma detection. RESULTS: 2,269,983 individuals returned FOB tests leading to 36,460 colonoscopies. Mean unadjusted caecal intubation rate was 95.2%, and mean withdrawal time for normal procedures was 9.2 min. The mean ADR per colonoscopist was 46.5%. The mean number of adenomas per procedure (MAP) was 0.91; the mean number of adenomas per positive procedure (MAP+) was 1.94. Perforation occurred after 0.09% of procedures. There were no procedure-related deaths. CONCLUSIONS: The NHS BCSP provides high-quality colonoscopy, as demonstrated by high caecal intubation rate, ADR and comfort scores, and low adverse event rates. Quality is achieved by ensuring BCSP colonoscopists meet a high standard before starting screening and through ongoing quality assurance. Measuring total adenoma detection (MAP and MAP+) as adjuncts to ADR may further enhance quality assurance.

Design and performance characterization of a new LISA-like (laser interferometer space antenna-like) gravitational reference sensor and torsion pendulum testbed.

In this paper, we present the design and performance of the upgraded University of Florida torsion pendulum facility for testing inertial sensor technology related to space-based gravitational wave observatories and geodesy missions. In particular, much work has been conducted on inertial sensor technology related to the Laser Interferometer Space Antenna (LISA) space gravitational wave observatory mission. A significant upgrade to the facility was the incorporation of a newly designed and fabricated LISA-like gravitational reference sensor (GRS) based on the LISA Pathfinder GRS. Its LISA-like geometry has allowed us to make noise measurements that are more representative of those in LISA and has allowed for the characterization of the mechanisms of noise induced on a LISA GRS and their underlying physics. Noise performance results and experiments exploring the effect of temperature gradients across the sensor will also be discussed. The LISA-like sensor also includes unique UV light injection geometries for UV LED based charge management. Pulsed and DC charge management experiments have been conducted using the University of Florida charge management group's technology readiness level 4 charge management device. These experiments have allowed for the testing of charge management system hardware and techniques as well as characterizations of the dynamics of GRS test mass charging. The work presented here demonstrates the upgraded torsion pendulum's ability to act as an effective testbed for GRS technology.

Iron overload in the Asian community.

Hereditary hemochromatosis is an iron overload disorder that can lead to the impairment of multiple organs and is caused by mutations in one or more different genes. Type 1 hemochromatosis is the most common form of the disease and results from mutations in the HFE gene. Juvenile hemochromatosis (JH) is the most severe form, usually caused by mutations in hemojuvelin (HJV) or hepcidin (HAMP). The autosomal dominant form of the disease, type 4, is due to mutations in the SLC40A1 gene, which encodes for ferroportin (FPN). Hereditary hemochromatosis is commonly found in populations of European origin. By contrast, hemochromatosis in Asia is rare and less well understood and can be masked by the presence of iron deficiency and secondary iron overload from thalassemia. Here, we provide a comprehensive report of hemochromatosis in a group of patients of Asian origin. We have identified novel mutations in HJV, HAMP, and SLC40A1 in countries not normally associated with hereditary hemochromatosis (Pakistan, Bangladesh, Sri Lanka, and Thailand). Our family studies show a high degree of consanguinity, highlighting the increased risk of iron overload in many countries of the developing world and in countries in which there are large immigrant populations from these regions.

Chemoprevention of oesophageal cancer and the AspECT trial.

Oesophageal cancer is on the rise and often present in an advanced state. Advances in surgical techniques, chemotherapy and radiotherapy have not changed the prognosis of oesophageal cancer over the last 20 years. With the unravelling of molecular biology of carcinogenesis in the oesophagus, there is a need for a paradigm shift from cancer treatment to prevention. Barrett's oesophagus is the commonest pre-malignant condition for development of oesophageal adenocarcinomas and is eminently suitable for the study of chemoprevention strategies. Now in its third year, the AspECT trial is the biggest, multicentre, randomised controlled clinical trial looking at the long-term chemoprevention effect of esomeprazole with or without aspirin. More than 85% of the participants tolerated the medications at the initial intended doses, and the drop-out rate has been 7%; the interim analysis is due in 2011.

National survey of UK endoscopists showing variation in diathermy practice for colonic polypectomy.

INTRODUCTION: Diathermy practice in colonic polypectomy has a poor evidence base. We surveyed endoscopists across the UK to gain an insight in current diathermy practice. METHODS: An eight-question survey was designed to be compact, easy to complete, while still capturing the relevant data. This national survey was circulated by the endoscopy committees of the British Society of Gastroenterology and Association of Coloproctology of Great Britain and Ireland. RESULTS: The survey was open between February and October 2016. Analysis showed: (1) 250/348 (71.8%) completed the full survey, 159 gastroenterologists (63.6%), 36 surgeons (14.4%), 34 gastroenterology trainees (13.6%), 21 others (8.4%); (2) predominant use of coagulation current for small pedunculated polypectomy, high rates of cold snare polypectomy for small sessile polyps (right 43.2% > left 34.4%); (3) a combination of coagulation and cutting current, or Endo Cut, was most popular for larger polypectomy; (4) low use of Endo Cut mode irrespective of size/location of polyp (17.2%-32.0%); (5) 204/250 (81.6%) used reduced current settings for right colon polypectomy; and (6) 208/250 (83.2%) were confident on knowledge and use of diathermy. CONCLUSION: This national survey exposes a wide variation in practice suggesting that colonoscopists employ diathermy modalities that they are comfortable with. As many complications are as direct result of thermal injury and polypectomy is the most frequent therapeutic intervention, appropriate training and formal guidance is lacking.

The WASh Trial: water-assisted sigmoidoscopy in the English Bowel Scope Screening Programme: study protocol for a randomized multicenter trial.

Background and study aims The English National Bowel Scope Screening Programme (BSSP) invites 55-year-olds for a one-off, unsedated flexible sigmoidoscopy (FSIG). Data from BSSP participant-reported experience studies shows 1 in 3 participants report moderate or severe discomfort. Water-assisted colonoscopy (WAS) may improve participants' comfort. The primary objective of this study is to ascertain if post-procedural participant-assessed pain is reduced in WAS compared with carbon dioxide (CO 2 ) insufflation, in invitees undergoing FSIG in BSSP. Patients and methods This is a multicenter, prospective, randomized, two-arm, single-blinded trial designed to evaluate the performance of WAS versus CO 2 insufflation in BSSP. Participants will be randomized to either CO 2 or WAS and will be asked to rate pain post-procedure. Key procedure-related data will be analyzed, including adenoma detection rates (ADR) and degree of sigmoid looping. A cost-effectiveness analysis of WAS versus CO 2 and a discrete choice experiment exploring preferences of participants for attributes of sigmoidoscopy will also be performed. Discussion This is the first trial in the United Kingdom (UK) to investigate the effects of WAS in a screening setting. If the trial shows WAS either reduces pain or increases ADR, this may result in a practice change to implement WAS in screening and non-screening endoscopic practice directly impacting on 256,000 people a year who will undergo BSSP FSIG by 2020. Trial funding came from National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB) supported by the NIHR Clinical Research Network. The trial is actively recruiting. ID: 35866 ISRCTN: 81466870.

A new torsion pendulum for gravitational reference sensor technology development.

We report on the design and sensitivity of a new torsion pendulum for measuring the performance of ultra-precise inertial sensors and for the development of associated technologies for space-based gravitational wave observatories and geodesy missions. The apparatus comprises a 1 m-long, 50 µm-diameter tungsten fiber that supports an inertial member inside a vacuum system. The inertial member is an aluminum crossbar with four hollow cubic test masses at each end. This structure converts the rotation of the torsion pendulum into translation of the test masses. Two test masses are enclosed in capacitive sensors which provide readout and actuation. These test masses are electrically insulated from the rest of the crossbar and their electrical charge is controlled by photoemission using fiber-coupled ultraviolet light emitting diodes. The capacitive readout measures the test mass displacement with a broadband sensitivity of 30 nm∕Hz and is complemented by a laser interferometer with a sensitivity of about 0.5 nm∕Hz. The performance of the pendulum, as determined by the measured residual torque noise and expressed in terms of equivalent force acting on a single test mass, is roughly 200 fN∕Hz around 2 mHz, which is about a factor of 20 above the thermal noise limit of the fiber.

Post traumatic intra thoracic spleen presenting with upper GI bleed!--a case report.

BACKGROUND: Isolated splenic vein thrombosis with left sided portal hypertension is a rare cause of upper gastrointestinal bleed. Diagnosis is difficult and requires a high index of suspicion, especially in patients presenting with gastrointestinal bleed in the presence of splenomegaly and normal liver function tests. CASE PRESENTATION: A 64 year old male presented with haematemesis and melaena. An upper gastrointestinal endoscopy revealed the presence of antral erosions in the stomach and fundal varices. A computerised tomography scan of abdomen confirmed the presence of a diaphragmatic tear and the spleen to be lying in the left hemi thorax. The appearances of the splenic vein on the scan were consistent with thrombosis. CONCLUSION: Left sided portal hypertension as a result of isolated splenic vein thrombosis secondary to trauma is rare. The unusual presentation of our case, splenic herniation into the left hemithorax, causing fundal varices leading to upper gastrointestinal bleed 28 years after the penetrating injury, makes this case most interesting. We believe that this has not been reported in literature before.

Paracetamol poisoning unmasking factor VII deficiency.

We report on an 18-year-old woman who took an impulsive overdose of paracetamol. The admission international normalized ratio (INR) was prolonged which resulted in her being transferred to a specialist hepatology unit. Her clinical condition and laboratory parameters did not correlate; this prompted investigation into her coagulation profile, which revealed a factor VII deficiency and explained the observed abnormalities of an elevated INR, normal partial thromboplastin time and normal liver function. There are no other reports of factor VII deficiency being identified as a result of paracetamol overdose.

Correlation of caecal intubation rate to volume: colonoscopists should undertake at least 120 procedures per year.

INTRODUCTION: The measurement of the quality of colonoscopy has been in the vanguard of quality improvement. The Joint Advisory Group on Gastrointestinal endoscopy (JAG) has issued guidance for practitioners to achieve caecal intubation rates (CIR) of ≥90% and to undertake ≥100 colonoscopies per annum. The British Society of Gastroenterology National Colonoscopy Audit published in 2012-2013 demonstrated a combined CIR of 92.3%. In 2012, we published data from 16 064 colonoscopies showing a combined CIR of 90.57%-both meeting JAG's standard. Analysis of our audit looked at the relationship of volume and outcome. CIR of operators performing ≥100 procedures per annum was 91.76%; those performing <100 was 87.77%. The 2-year data we collected involved 120+ operators. This provided an opportunity to study the correlation between volume and CIR in detail. METHODS: We analysed 129 operator records who had undertaken 20-399 procedures per annum (total 12 594). Each operator's volume was plotted against CIR as individuals and groups of operators undertaking a similar annual volume. 9859 procedures (78.3%) were performed by operators undertaking 20-199 procedures per annum (120 operators); this subgroup was further analysed. RESULTS: When plotting individuals and groups of individuals who have undertaken a similar annual volume against CIR, the trend-lines cross a 90% CIR at a volume of 120-125 procedures. The subgroup analysis showed the trend-line crossing at 110-120 procedures. CONCLUSIONS: This detailed analysis of 12 594 colonoscopies over 2 years suggests that JAG should advise operators to undertake ≥120 procedures per annum to support the quality standard for CIR of ≥90%.

Scope to improve: a multi-centre audit of 16 064 colonoscopies looking at caecal intubation rates, over a 2-year period.

OBJECTIVE: Colonoscopy is the 'gold standard' assessment for large bowel mucosal pathology, but a complete examination is essential. The first national colonoscopy audit carried out in 1999 demonstrated caecal intubation rates (CIRs) of 56.9%. As a result, the Joint Advisory Group (JAG) on gastrointestinal endoscopy launched a programme of continuous quality improvement. JAG recommends that practitioners undertake 100+ procedures per annum with a target CIR of 90%. This current audit provides an assessment of performance against this quality standard. DESIGN: Data were collected from all procedures undertaken in 2008-2009 from six hospitals across three English regions. RESULTS: 16064 colonoscopies performed: CIR = 90.57% (95% CI 90.11% to 91.01%). Operators doing 100+ procedures per annum, CIR=91.76% (91.24% to 92.25%). Operators doing <100 procedures per annum, CIR=87.77% (86.82% to 88.67%). Gastroenterologists, CIR=91.01% (90.32% to 91.70%). Surgeons, CIR=91.03% (90.27% to 91.79%). Other practitioners, CIR=81.51% (78.79% to 84.22%). Bowel cancer screening programme (BCSP) colonoscopies, CIR=97.71% (97.07% to 98.34%). Non-screening colonoscopies, CIR=88.31% (95% CI 87.68% to 88.94%). CONCLUSION: This audit of 16064 colonoscopies across three regions demonstrates aggregated achievement of the CIR quality standard. However, there is a significant performance gap when comparing BCSP colonoscopists with non-screening colonoscopists and the overall CIR of >90% is supported by the volume of BCSP colonoscopy. Endoscopists performing low volume colonoscopy (<100 per annum), have CIR of <90%. Endoscopists with low volume practice who do not meet the quality standards should engage in skills augmentation plus further training and increase volume of colonoscopy with local mentorship, or stop performing colonoscopy.