In-flight determination of spacecraft magnetic bias independent of attitude

A simple algorithm for the in-flight determination of the magnetic bias of a spacecraft is presented. The algorithm, developed for use during the Hubble Space Telescope mission, determines this bias independently of any attitude estimates and requires no spacecraft sensor data other than that from the spacecraft magnetometer(s). Estimates of the algorithm's accuracy and results from a number of numerical studies on the use of this algorithm are also presented

Examining the Personal and Institutional Determinants of Research Productivity in Hospitality and Tourism Management

The transition toward a post-capitalist knowledge-oriented economy has resulted in an increasingly competitive academic environment, where the success of faculty is dependent on their research productivity. This study examines the personal and institutional determinants of the quantity and quality of the research productivity of hospitality and tourism management faculty in US institutions. A survey of 98 faculty found that a different set of determinants impact the quantity and quality aspects of research productivity. Also, institutional determinants were found to play a larger role, indicating the need for administrators to strive for a culture that is supportive of and an infrastructure that is conducive to their faculty’s research success. The authors use the field of hospitality and tourism management as a case study to develop a holistic and cohesive framework for knowledge worker productivity that can guide the evaluation, hiring, and development of researchers

Evaluating PET-CT in the detection and management of recurrent cervical cancer: Systematic reviews of diagnostic accuracy and subjective elicitation

Background: Positron emission tomography-computed tomography (PET-CT) is recommended to triage women for exenterative surgery and surveillance after treatment for advanced cervical cancer. Objective: To evaluate diagnostic accuracy of additional whole body PET-CT compared with CT/magnetic resonance imaging (MRI) alone in women with suspected recurrent/persistent cervical cancer and in asymptomatic women as surveillance. Design: Systematic reviews. Subjective elicitation to supplement diagnostic information. Search strategy/Selection criteria/Data collection and analysis: Searches of electronic databases were performed to June 2013. Studies in women with suspected recurrent/persistent cervical cancer and in asymptomatic women undergoing follow up with sufficient numeric data were included. We calculated sensitivity, specificity and corresponding 95% confidence intervals. Meta-analyses employed a bivariate model that included a random-effects term for between-study variations (CT studies) and univariate random effects meta-analyses (PET-CT studies) for sensitivity and specificity separately. Subjective elicitation: Prevalence of recurrence and the accuracy of imaging elicited using the allocation of points technique. Coherence of elicited subjective probabilities with estimates in the literature examined. Results: We identified 15 relevant studies; none directly compared additional PET-CT with MRI or CT separately. Most CT and MRI studies used older protocols and the majority did not distinguish between asymptomatic and symptomatic women. Meta-analysis of nine PET-CT studies in mostly symptomatic women showed sensitivity of 94.8 (95% CI 91.2-96.9), and specificity of 86.9% (95% CI 82.2-90.5). The summary estimate of the sensitivity of CT for detection of recurrence was 89.64% (95% CI 81.59-94.41) and specificity was 76% (95% CI 43.68-92.82). Meta-analysis for MRI test accuracy studies was not possible because of clinical heterogeneity. The sensitivity and specificity of MRI in pelvic recurrence varied between 82 and 100% and between 78 and 100%, respectively. Formal statistical comparisons of the accuracy of index tests were not possible. Subjective elicitation provided estimates comparable to the literature. Subjective estimates of the increase in accuracy from the addition of PET-CT were less than elicited increases required to justify the use in PET-CT for surveillance. Conclusion: Evidence to support additional PET-CT is scarce, of average quality and does not distinguish between application for surveillance and diagnosis. Guidelines recommending PET-CT in recurrent cervical cancer need to be reconsidered in the light of the existing evidence base

Method for producing angled optical fiber tips in the laboratory

A simple laboratory method is presented for producing optical fibers with tips polished at various angles. Angled optical fiber tips are used in applications such as optical sensing and remote laser surgery, where they can be used to control the angle of light leaving the fiber or direct it to the side. This allows for greater control and allows areas to be reached that otherwise could not. Optical fibers were produced with tip angles of 45 deg using a Perspex mounting block with an aluminum base plate. The dispersion of light leaving the tip was tested using a blue (470 nm) LED. The angle imposed an angular shift on the light diffracting out of the tip of approximately 30 deg. Additionally, some light reflected from the tip surface to diffract at 90 deg through the side of the fiber. These observations are consistent with theory and those seen by other studies, validating the method. The method was simple to perform and does not require advanced manufacturing tools. The method is suitable for producing small quantities of angle-tipped optical fibers for research applications

Fiber-optic fluorescence-quenching oxygen partial pressure sensor using platinum octaethylporphyrin

The development and bench testing of a fiber-optic oxygen sensor is described. The sensor is designed for measurement of tissue oxygen levels in the mucosa of the digestive tract. The materials and construction are optimized for insertion through the mouth for measurement in the lower esophagus. An oxygen-sensitive fluorescence-quenching film was applied as a solution of platinum octaethylporphyrin (PtOEP) poly(ethyl methacrylate) (PEMA) and dichloromethane and dip coated onto the distal tip of the fiber. The sensor was tested by comparing relative fluorescence when immersed in liquid water at 37°C, at a range of partial pressures (0–101 kPa). Maximum relative fluorescence at most oxygen concentrations was seen when the PtOEP concentration was 0.1  g.L−10.1  g.L−1, four layers of coating solution were applied, and a fiber core radius of 600 μm was selected, giving a Stern–Volmer constant of 0.129  kPa−10.129  kPa−1. The performance of the sensor is suitable for many in vivo applications, particularly mucosal measurements. It has sufficient sensitivity, is sterilizable, and is sufficiently flexible and robust for insertion via the mouth without damage to the probe or risk of harm to the patient

Dual pO₂/pCO₂ fibre optic sensing film

A fibre optic multi-sensor has been developed for biomedical sensing applications using a tip coating solution sensitive to both oxygen and carbon dioxide. An oxygen sensitive phosphorescence quenching complex based on platinum octaethylporphyrin (PtOEP) was combined with a carbon dioxide sensitive phosphorescence compound based on 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). When excited by blue light (470 nm), the resultant coating had two fluorescent peaks at 515 nm (green) and 645 nm (red) which responded to partial pressure of CO2 and O2 respectively. The sensor was tested in vitro and shown to be able to measure CO2 and O2 simultaneously and in real time, with calibration constants of 0.0384 kPa−1 and 0.309 kPa−1 respectively. The O2 sensitive peak received some overlap from the 515 nm peak (0.38% of peak intensity) as well as some cross-sensitivity (maximum, 5.1 kPa pCO2 gave a measurement equivalent to 0.43 kPa of O2, a ratio of 0.08 : 1). However, these effects can be subtracted from measurements and no significant cross-sensitivity or overlap was seen in CO2 measurements from O2. This novel compound presents great potential for use in medical sensors and we expect it to be important to a wide range of future applications

A fiberoptic sensor for tissue carbon dioxide monitoring

We present a new fiberoptic carbon dioxide sensor for transcutaneous and mucosa (indwelling) blood gas monitoring. The sensor is based on optical fluorescence of molecules sensitive to pH changes associated with dissolved CO2. A three layer chemical coating was dip-coated onto the distal tip of an optical fiber (600μm core radius). It contained the 50mg/ml 'polym H7', a coating polymer bonded to a fluorescence indicator dye, along with 125mg/ml of the transfer agent tetraoctylammonium hydroxide (TONOH). Light from a blue (460 nm) LED was launched into the fiber to excite the sensing film. The sensing film fluoresced green (530 nm), the intensity of which decreased in the presence of CO2. The sensor was tested in vitro, finding a correlation between change in fluorescence (in AU) and aqueous CO2 concentration with a minimum detection threshold of 40%. The sensor is being developed for medical applications where its small size and ability to continuously monitor the partial pressure of CO2 (PCO2) will make it an extremely useful diagnostic tool

Lung protection after severe thermal burns with adenosine, lidocaine, and magnesium (ALM) resuscitation and importance of shams in a rat model

The management of severe burns remains a complex challenge. Adenosine, lidocaine, and magnesium (ALM) resuscitation therapy has been shown to protect against hemorrhagic shock and traumatic injury. The aim of the present study was to investigate the early protective effects of small-volume ALM fluid resuscitation in a rat model of 30% total body surface area (TBSA) thermal injury. Male Sprague–Dawley rats (320–340 g; n = 25)were randomly assigned to: 1) Sham (surgical instrumentation and saline infusion, without burn, n = 5), 2) Saline resuscitation group (n = 10), or 3) ALM resuscitation group (n = 10). Treatments were initiated 15-min after burn trauma, including 0.7 mL/kg 3% NaCl ± ALM bolus and 0.25–0.5 mL/kg/h 0.9% NaCl ± ALM drip, with animals monitored to 8.25-hr post-burn. Hemodynamics, cardiac function, blood chemistry, hematology, endothelial injury markers and histopathology were assessed. Survival was 100% for Shams and 90% for both ALM and Saline groups. Shams underwent significant physiological, immune and hematological changes over time as a result of surgical traums. ALM significantly reduced malondialdehyde levels in the lungs compared to Saline (P = .023), and showed minimal alveolar destruction and inflammatory cell infiltration (P < .001). ALM also improved cardiac function and oxygen delivery (21%, P = .418 vs Saline), reduced gut injury (P < .001 vs Saline), and increased plasma adiponectin (P < .001 vs baseline). Circulating levels of the acute phase protein alpha 1-acid glycoprotein (AGP) increased 1.6-times (P < .001), which may have impacted ALM's therapeutic efficacy. We conclude that small-volume ALM therapy significantly reduced lung oxidative stress and preserved alveolar integrity following severe burn trauma. Further studies are required to assess higher ALM doses with longer monitoring periods

Positron emission tomography/computerised tomography imaging in detecting and managing recurrent cervical cancer: systematic review of evidence, elicitation of subjective probabilities and economic modelling.

© Queen’s Printer and Controller of HMSO 2013. This work was produced by Meads et al. under the terms of a commissioning contract issued by the Secretary of State for Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising.Cancer of the uterine cervix is a common cause of mortality in women. After initial treatment women may be symptom free, but the cancer may recur within a few years. It is uncertain whether it is more clinically effective to survey asymptomatic women for signs of recurrence or to await symptoms or signs before using imaging.National Institute for Health Research Health Technology Assessment programm