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Alzheimer's disease is a devastating neurodegenerative disease with a dramatically increasing prevalence and no disease-modifying treatment. Inflammatory lifestyle factors increase the risk of developing Alzheimer's disease. Zinc deficiency is the most prevalent malnutrition in the world and may be a risk factor for Alzheimer's disease potentially through enhanced inflammation, although evidence for this is limited. Here we provide epidemiological evidence suggesting that zinc supplementation was associated with reduced risk and slower cognitive decline, in people with Alzheimer's disease and mild cognitive impairment. Using the APP/PS1 mouse model of Alzheimer's disease fed a control (35 mg/kg zinc) or diet deficient in zinc (3 mg/kg zinc), we determined that zinc deficiency accelerated Alzheimer's-like memory deficits without modifying amyloid β plaque burden in the brains of male mice. The NLRP3-inflammasome complex is one of the most important regulators of inflammation, and we show here that zinc deficiency in immune cells, including microglia, potentiated NLRP3 responses to inflammatory stimuliin vitro, including amyloid oligomers, while zinc supplementation inhibited NLRP3 activation.APP/PS1mice deficient in NLRP3 were protected against the accelerated cognitive decline with zinc deficiency. Collectively, this research suggests that zinc status is linked to inflammatory reactivity and may be modified in people to reduce the risk and slow the progression of Alzheimer's disease.SIGNIFICANCE STATEMENTAlzheimer's disease is a common condition mostly affecting the elderly. Zinc deficiency is also a global problem, especially in the elderly and also in people with Alzheimer's disease. Zinc deficiency contributes to many clinical disorders, including immune dysfunction. Inflammation is known to contribute to the risk and progression of Alzheimer's disease; thus, we hypothesized that zinc status would affect Alzheimer's disease progression. Here we show that zinc supplementation reduced the prevalence and symptomatic decline in people with Alzheimer's disease. In an animal model of Alzheimer's disease, zinc deficiency worsened cognitive decline because of an enhancement in NLRP3-driven inflammation. Overall, our data suggest that zinc status affects Alzheimer's disease progression, and that zinc supplementation could slow the rate of cognitive decline.

Introduction\ud \ud Patients with cancer who develop small bowel obstruction are at high risk of malnutrition and morbidity following compromise of gastrointestinal tract continuity. This study aimed to characterise current management and outcomes following malignant small bowel obstruction.\ud \ud \ud \ud Methods\ud \ud A prospective, multicentre cohort study of patients with small bowel obstruction who presented to UK hospitals between 16th January and 13th March 2017. Patients who presented with small bowel obstruction due to primary tumours of the intestine (excluding left-sided colonic tumours) or disseminated intra-abdominal malignancy were included. Outcomes included 30-day mortality and in-hospital complications. Cox-proportional hazards models were used to generate adjusted effects estimates, which are presented as hazard ratios (HR) alongside the corresponding 95% confidence interval (95% CI). The threshold for statistical significance was set at the level of P ≤ 0.05 a-priori.\ud \ud \ud \ud Results\ud \ud 205 patients with malignant small bowel obstruction presented to emergency surgery services during the study period. Of these patients, 50 had obstruction due to right sided colon cancer, 143 due to disseminated intraabdominal malignancy, 10 had primary tumours of the small bowel and 2 patients had gastrointestinal stromal tumours. In total 100 out of 205 patients underwent a surgical intervention for obstruction. 30-day in-hospital mortality rate was 11.3% for those with primary tumours and 19.6% for those with disseminated malignancy. Severe risk of malnutrition was an independent predictor for poor mortality in this cohort (adjusted HR 16.18, 95% CI 1.86 to 140.84, p = 0.012). Patients with right-sided colon cancer had high rates of morbidity.\ud \ud \ud \ud Conclusions\ud \ud Mortality rates were high in patients with disseminated malignancy and in those with right sided colon cancer. Further research should identify optimal management strategy to reduce morbidity for these patient groups.

Purpose The purpose of this article was to conduct an extensive literature review of nurse practitioners (NPs) in orthopaedic surgical settings to delineate whether a need exists for NPs in these settings. Background Due to physician shortages and changes in healthcare, patients are experiencing difficulty accessing orthopaedic surgeons. To meet this need, NPs are becoming an essential part of the multidisciplinary orthopaedic team in Level 1 trauma hospitals. Results Nurse practitioners are qualified and competent to work in a variety of orthopaedic settings including preoperative clinics, primary care orthopaedic clinics, and pre-/postoperative care within the hospital. The benefits of NPs in orthopaedic surgical settings includes increased access to care, improved team communication, decreased length of stay, improved quality of care, and improved patient satisfaction. Moreover, NPs meet patient needs while surgeons are operating, and have a positive impact on resident surgeon education. Conclusion A need exists for NPs in orthopaedic surgical settings to both improve access to healthcare for patients and reduce the burden on orthopaedic surgeons.

Background Attending outpatient appointments at Great Ormond Street Hospital can be time-consuming, expensive, and inconvenient for families. The aim of the study was to gain an understanding of the issues faced by families in attending, in order to develop techniques to try to alleviate them. Methods Authors created a questionnaire addressing common issues families face when attending clinics: we enquired about cost and time of travel, missed days at work, loss of earnings for parents, missed school, childcare for siblings, and preference for either a telephone consultation or outpatient attendance for future appointments. Questionnaires were given to patients attending an Orthopaedic Clinic between the months of June and July 2017. Questionnaires were all collected on the same day of the week. Data was input and analysed in Microsoft Excel. Results 17 questionnaires were collected from 3 Orthopaedic clinics. Average time to travel was approximately 2 hour 30 mins (Range 15 mins – 12 hours). Total cost of travel was approximately £25 per family. 10/16 Family member had to take time out of work to bring child to clinic. 6/16 had loss of earnings. 8/15 had to arrange childcare. 14/17 patients had to miss school. 5/14 had to apply to school to get leave for their child. 13/16 preferred to attend the outpatient appointment rather than having a telephone consultation in the future. Conclusion Despite many inconveniences in attending outpatient appointments, families appear to prefer having face-to-face appointments with specialists over telephone consultations for future appointments. This study has highlighted and confirmed various issues families face attending OPD for just one speciality. As a leading hospital-care provider we should endeavour to do all we can to lessen this burden.

Background The optimal timing of cholecystectomy for patients admitted with acute gallbladder pathology is unclear. Some studies have shown that emergency cholecystectomy during the index admission can reduce length of hospital stay with similar rates of conversion to open surgery, complications and mortality compared with a ‘delayed’ operation following discharge. Others have reported that cholecystectomy during the index acute admission results in higher morbidity, extended length of stay and increased costs. This study examined the cost-effectiveness of emergency versus delayed cholecystectomy for acute benign gallbladder disease. Methods Using data from a prospective population-based cohort study examining the outcomes of cholecystectomy in the UK and Ireland, a model-based cost–utility analysis was conducted from the perspective of the UK National Health Service, with a 1-year time horizon for costs and outcomes. Probabilistic sensitivity analysis was used to investigate the impact of parameter uncertainty on the results obtained from the model. Results Emergency cholecystectomy was found to be less costly (£4570 versus £4720; €5484 versus €5664) and more effective (0·8868 versus 0·8662 QALYs) than delayed cholecystectomy. Probabilistic sensitivity analysis showed that the emergency strategy is more than 60 per cent likely to be cost-effective across willingness-to-pay values for the QALY from £0 to £100 000 (€0–120 000). Conclusion Emergency cholecystectomy is less costly and more effective than delayed cholecystectomy. This approach is likely to be beneficial to patients in terms of improved health outcomes and to the healthcare provider owing to the reduced costs.

The Peano-Gosper space-filling curve provides an excellent framework for designing planar antenna array distributions with modular architectures and suppressed sidelobes over a relatively wide bandwidth. The curve consists of a self-avoiding path that intersects a triangular lattice and its construction is based on the iterative application of a generating curve. There exist a number of other recently discovered curves, coined generalized Gosper curves, that possess properties similar to those of the Peano-Gosper curve but are based on larger and more complex generating curves. In this paper these generalized curves will be examined as the framework for antenna array layouts. It will be shown that arrays based on these curves have a number of excellent characteristics while offering modular array configurations and sizes that are not inherent to Peano-Gosper arrays. Moreover, when combined with a simple recursive-perturbation technique, the element distributions of these arrays can be efficiently adjusted to generate designs with bandwidths that far exceed that of standard periodic- and triangular-lattice arrays. The efficacy of this technique will be demonstrated through design examples, including one that has more than a 10:1 bandwidth. Full-wave simulations of a wideband patch array will also be used to investigate the effects of mutual coupling on these array distributions.

Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. This Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylate and show parts-per-billion per root hertz sensitivity measured in real-time.

The technology of the rotational moulding of plastics has improved dramatically in recent years due to the recognition that measuring the temperature inside the mould is fundamental to process control. The next major advance will be made when the benefits of controlling the pressure inside the mould are fully utilized. A drawback of the rotational moulding process has always been the surface pinholes and internal bubbles that occur in the moulded part. These occur because, as the powder particles melt and coalesce, they trap pockets of air and it takes a considerable time for these to disappear. It is known that factors such as the viscosity of the polymer melt, the shape of the powder particles, the particle size and size distribution, the mould release agent and the metal used for the mould all affect the pinholing problem. However, the major factor that influences pinhole removal is mould pressure. If pressure is applied at a strategic point in the heating cycle, it can force trapped air out of the melted plastic. Indeed the use of mould pressurization can offer additional benefits such as cycle time reduction and significant improvements in the mechanical properties of the moulded part. However, few moulders make any attempt to monitor or control the mould pressure, mainly because its effect is not understood. This paper explains why mould pressure control throughout the moulding cycle is crucial to the rotational moulding industry in terms of, firstly, achieving good part quality and, secondly, reducing cycle times. It is also suggested that a fundamental change from passive venting to active venting of the mould is an important development that must occur in this industry.

A system is described that employs a diode-pumped Nd:YAG continuous-wave laser source servolocked to a three-mirror optical cavity and an analog detection circuit that extracts the ring-down rate from the exponentially decaying ring-down waveform. This scheme improves on traditional cavity ring-down spectroscopy setups by increasing signal acquisition rates to tens of kilohertz and reducing measurement noise sources. For example, an absorption spectrum of a weak CO2 transition at 1064 nm is obtained in less than 10 s at a spectral resolution of 75 kHz employing a cavity with an empty-cavity ring-down decay lifetime of 2.8 μs and a total roundtrip path length of 42 cm. The analog detection system enables laser frequency scan rates greater than 500 MHz/s. The long-term sensitivity of this system is 8.8×10−12 cm−1 Hz−1/2 and the short-term sensitivity is 1.0×10−12 cm−1 Hz−1/2.

Pulse stacking, or synchronous pumping, is a novel approach that offers important advantages in cavity ring-down spectroscopy. Using an ultrashort pulse, high repetition rate laser source we have shown that it is possible to resonantly stack pulses in a high finesse cavity, significantly enhancing the decay wave forms obtained when the laser source is abruptly terminated. We have achieved signal-to-noise ratio improvements of several orders of magnitude compared to single pulse injection systems, demonstrating a sensitivity of 2×10−9 cm−1 at 5.38 μm.

Polarization-selective optical heterodyne detection is shown to enhance the practical sensitivity of cavity ring-down spectroscopy. Initial experiments demonstrate a signal-to-noise ratio above 31 dB. Minor improvements should yield shot-noise-limited operation.

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Serial kinetic modeling is commonly used in hemodialysis to assess the adequacy of dialysis. A variety of problems lead to declining Kt/V in previously stable patients. These include noncompliance, vascular access recirculation, and dialyzer dysfunction. The purpose of this study was to find the relative frequencies of these problems in a group of patients undergoing routine hemodialysis. Simultaneous urea kinetic modeling and access recirculation were tested during 3 consecutive months. The baseline Kt/V was defined as the average of each patient's Kt/V values obtained during the previous 4 mo. A clinically important fall in Kt/V was defined as a decline ofor =0.2 if the baseline Kt/V wasor =1.2, or a decline ofor =0.1 if the baseline Kt/V was1.2. Ninety-three of 375 (25%) sessions met the criteria for a significant decline in urea kinetic modeling. The baseline Kt/V in this group was 1.33 +/- 0.20 (mean +/- SEM) and declined to 1.02 +/- 0.18 in the abnormal month (P0.05). In 42% of instances with a decline of Kt/V, reduced blood processing due to a lower blood flow or shorter time than prescribed was responsible. Recirculation of12% was found in 25% of sessions with a decrease in Kt/V. These patients most often had access dysfunction or reversed needles. The remaining one-third of patients with decreases in Kt/V had no problem identified, and subsequent monthly kinetic modeling results returned to baseline. These results suggest that analysis of falling urea kinetic modeling results should include a careful review of the dialysis record for reductions in prescribed time or blood flow rates followed by vascular access testing. If these evaluations are unrevealing, urea kinetic modeling results usually return to baseline in the next month.

We present a new variant of the Cavity Ringdown Spectroscopy (CRDS) that is able to scan across more than 1400 nm of spectral bandwidth around 6000 nm, acquiring and analysing more than 150,000 spectral datapoints in less than four seconds.

We present a new variant of the Cavity Ringdown Spectroscopy (CRDS) that is able to scan across more than 1400 nm of spectral bandwidth, acquiring and analysing more than 150,000 spectral datapoints in less than four seconds.

The rotational molding processing method for plastics is steadily expanding its product range and market areas. However, a drawback of the process has always been the surface pin-holes and internal bubbles that occur in the products because of the inherent nature of the process. In an attempt to alleviate this problem, a program of research has been carried out to investigate the factors that affect the formation of the bubbles and, more importantly, that influence their removal. This paper describes the results of the first stage of this work and covers variables such as the viscosity of the polymer melt, the nature of the pigmentation, the particle size, shape and distribution in the powder feedstock, the mold release agent, the metal used for the mold, the temperature distribution in the mold, etc. It is shown that the mechanisms of bubble formation and removal can be explained and having done this, steps can be taken to ensure that once formed, the bubbles will decrease in size rapidly. This provides significant advantages in terms of reduced cycle time and improved product quality.

This paper presents results from a pulsed-laser cavity ring-down spectrometer with novel field programable gate array real-time data collection. We show both theoretically and experimentally that the data extraction can be achieved from a single cavity ringdown event, and that the absorbance can be determined without the need to fit the ringdown time explicitly. This methodology could potentially provide data acquisition rate up to 1 MHz, with the accuracy and precision comparable to nonlinear least squares fitting algorithms.

A consortium of researchers at University of New South Wales (UNSW@ADFA), and Loyola University New Orleans (LU NO), together with Australian government security agencies (e.g., Australian Federal Police), are working to develop highly sensitive laser-based forensic sensing strategies applicable to characteristic substances that pose chemical, biological and explosives (CBE) threats. We aim to optimise the potential of these strategies as high-throughput screening tools to detect prohibited and potentially hazardous substances such as those associated with explosives, narcotics and bio-agents.

One biceps muscle of 8 patients with Duchenne muscular dystrophy was injected at 55 sites with a total of 55 million viable, purified, and contamination-free normal myoblasts (myoblast transfer). The other biceps of each patient was injected with a placebo to serve as a control. The procedure was blinded to the patients, parents, and investigators. Myoblasts derived from a biopsy specimen of the fathers were cultured and purified under strict conditions and carefully screened for microbial contamination. All patients received cyclophosphamide for immunosuppression for 6 or 12 months. No serious complications were observed after myoblast transfer, indicating that the procedure is safe. The overall therapeutic efficiency of myoblast transfer was poor as judged by the results in maximal voluntary force generation, dystrophin content of the muscle, magnetic resonance imaging of the muscle, and the lack of donor-derived DNA and dystrophin messenger RNA in the injected muscle. An improved efficiency of the take of myoblasts might be achieved by using younger cells and injecting the myoblasts with a myonecrotic agent (to increase the prevalence of regeneration) and a basal laminal fenestrating agent.

FINE392: Technology Art Studio is an innovative course developed in collaboration with Engineering and Fine Arts at the University of Waterloo, which crosses disciplinary boundaries and provides a unique multi-disciplinary experience for senior engineering students. In the course, students form interdisciplinary pairs and collaborate on technology-mediated sculptural works. Our previous work has shown that the interdisciplinary collaboration can act as a catalyst for transformative learning, and that the emergence of learning transformations is dependent on the success of the collaboration. In this paper we investigate the relationship between learning transformation, collaboration, and student project grades. We note that the success of the collaboration seems only loosely connected to project quality and grade level. We include a discussion of factors we believe contribute to this somewhat non-intuitive result. We further discuss how these factors may be mitigated through course design to better allow successful groups to achieve the full potential of their collaboration.

Cavity ringdown spectra of ammonia at 10 parts in 10(9) by volume (ppbv) and higher concentrations were recorded by use of a 16-mW continuous-wave quantum-casacde distributed-feedback laser at 8.5 mum whose wavelength was continuously temperature tuned over 15 nm. A sensitivity (noise-equivalent absorbance) of 3.4x10(-9) cm(-1) Hz(-1/2) was achieved for ammonia in nitrogen at standard temperature and pressure, which corresponds to a detection limit of 0.25 ppbv.

There is a real clinical need to detect, separate, classify and ultimately monitor bio-medical signals over long periods of time. This would permit such applications as monitoring operator state using electroencephalogram (EEG) and determining foetal well-being in labour non-invasively. The long-term monitoring problem is, however, very challenging as bio-medical signals can be masked by much stronger interference, occur intermittently and the analysis may have to be performed in real-time (i.e. on-line) and over periods lasting several hours if not days. In this paper, to help overcome these problems, blind signal separation (BSS) methods that are capable of long-term monitoring are presented. It is established that block-based BSS approaches can be developed into efficient moving (exponentially fading) window approaches where the permutation problem in each window is overcome and subsequently the statistics of the signals can be updated and tracked. This approach is called the tracking blind signal separation (BLISS) algorithm. To provide a demonstration of concept, separation results are presented for EEG and twin foetal electrocardiogram (ECG) analysis.

Summary form only given, as follows. Cavity ring-down spectroscopy (CRDS) is newly developed spectroscopic technique which may be used to determine the concentration of very dilute gas-phase species present in hostile environments. Unlike traditional absorption techniques which measure the attenuation of light passing through a sample, in CRDS light from a pulsed laser is injected into a high-finesse cavity formed by two or more high reflectivity mirrors. Light leaking from the resonator through one of the mirrors is then used to measure the rate of decay of the pulse of light within the cavity. Absorption by species present within the resonator increase the rate of decay of light in the cavity. Therefore, by measuring this ring-down rate with and without sample present within the resonator, the absorbance of the sample may be measured and its absolute concentration determined. The largest advantage of CRDS is its insensitivity to fluctuations in the intensity of the light source; these fluctuations limit the sensitivity of traditional absorption techniques. Furthermore, since the decay of coherent light from the resonator is being detected, CRDS may be used to measure species in environments with high background radiation levels such as flames and discharges. Advancements in the use of this technique to measure the concentration of species in hostile environments will be discussed as well as the application of continuous-wave laser sources to the technique.

Optical cavity enhancement is a highly desirable process to make sensitive direct-absorption spectroscopic measurements of unknown substances, such as explosives, illicit material, or other species of interest. This paper reports advancements in the development of real-time cavity ringdown spectroscopy over a wide-bandwidth, with the aim to make headspace measurements of molecules at trace levels. We report results of two pulsed quantum cascade systems operating between (1200 to 1320)cm(-1) and (1316 to 1613)cm(-1) that measure the headspace of nitromethane, acetonitrile, acetone, and nitroglycerin, where the spectra are obtained in less than four seconds and contain at least 150,000 spectral wavelength datapoints.

Photoacoustic spectra of ammonia and water vapor were recorded by use of a continuous-wave quantum-cascade distributed-feedback (QC-DFB) laser at 8.5 ?m with a 16-mW power output. The gases were flowed through a cell that was resonant at 1.6??kHz, and the QC-DFB source was temperature tuned over 35??nm for generation of spectra or was temperature stabilized on an absorption feature peak to permit real-time concentration measurements. A detection limit of 100 parts in 109 by volume ammonia at standard temperature and pressure was obtained for a 1-Hz bandwidth in a measurement time of 10??min.

Introduction Endoscopic placement of oesophageal stent across the benign oesophageal perforation and postoperative oesophageal anastomotic leak might help to control the sepsis and reduce the associated mortality and morbidity. Aims/Background The aim of this review is to assess the safety and effectiveness of oesophageal stents in the management of benign oesophageal perforation and oesophageal anastomotic leaks. Method All the published case series reporting the use of metallic and plastic stents in the management of postoperative anastomotic leaks, spontaneous oesophageal perforations, iatrogenic oesophageal perforations were identified from MEDLINE, EMBASE and PUBMED (1990–2012). Primary outcomes assessed were technical success rates and complete healing rates. Secondary outcomes assessed were stent migration rates, stent perforation rates, duration of hospital stay, time to stent removal and mortality rates. A pooled analysis was performed and subgroup analysis was performed for plastic vs metallic stents and anastomotic leaks vs perforations separately. Results 27 case series with 340 patients were included. Technical and clinical success rates of stenting were 91% and 81% respectively. Stent migration rates were significantly higher with plastic stents compared to metallic stents (40/148 vs 13/117 patients respectively; p=0.001). Patients with metallic stents had significantly higher incidence of post procedure strictures (p=0.006). There was no significant difference in the primary or secondary outcomes when stenting was performed for anastomotic leaks or perforations. Conclusion Endoscopic management of oesophageal anastomotic leaks and perforations with the use of oesophageal stents is technically feasible. It appears to be safe and effective when performed along with mediastinal or pleural drainage.

On-load tap-changers may represent only 5-100 % of the capital cost of a supergrid power transformer yet their operational performance and reliability is critical to realising the full asset life of the transformer. In addition, tap-changer inspections largely govern the frequency and duration of transformer circuit outages and represent a high proportion of transformer maintenance costs. This paper presents a summary of the National Grid Company's (UK) experience in such tap-changers in recent years. This experience, the changes in specification and the user-supplier relationships described are believed to be representative of a major electric utility. (7 pages)

Following a beyond design basis accident (BDBA) in an advanced gas cooled reactor (AGR), leading to an interruption in post-trip heat removal, several hours are available to re-establish satisfactory operation of the reactor's emergency cooling systems. To aid the operator, following a BDBA, symptom based emergency response guidelines (SBERGs) have been developed. The guidance contained within the SBERGs is relevant to situations where the fuel is largely contained within the fuel pins and the geometry of the fuel pins and other circuit components is essentially undisturbed. Operator/emergency control guidance for degraded core conditions is contained within the severe accident guidelines (SAGs). Guidance to the operator is thus given in event based procedures contained in station operating manuals (mandatory), SBERGs and SAGs (both advisory). (5 pages)

In this paper we report on the development of a Fourier-transform based signal processing method for laser-locked Continuous Wave Cavity Ringdown Spectroscopy (CWCRDS). Rather than analysing single ringdowns, as is the norm in traditional methods, we amplitude modulate the incident light, and analyse the entire waveform output of the optical cavity; our method has more in common with Cavity Attenuated Phase Shift Spectroscopy than with traditional data analysis methods. We have compared our method to Levenburg-Marquardt non linear least squares fitting, and have found that, for signals with a noise level typical of that from a locked CWCRDS instrument, our method has a comparable accuracy and comparable or higher precision. Moreover, the analysis time is approximately 500 times faster (normalised to the same number of time domain points). Our method allows us to analyse any number of periods of the ringdown waveform at once: this allows the method to be optimised for speed and precision for a given spectrometer.

When the frequency of light coupled into a cavity is suddenly shifted, the radiation emanating from the input port of the previously excited cavity can beat with the reflection of the frequency-shifted input on the surface of a photodetector. When the beat frequency is stable, the time decay of the resulting optical heterodyne signal can be used to measure intracavity absorption spectra with near quantum-limited sensitivity.

To determine whether administration of nitrous oxide, 50% and 70%, could provide analgesia and anxiolysis during venous cannulation in pediatric patients, 165 ASA Physical Status 1 patients scheduled for elective surgery were studied. Children, 3 weeks to 18 yr of age, were randomly assigned either to receive nitrous oxide, 50% or 70% in oxygen, or 100% oxygen via mask or to a group breathing room air, for 3 min prior to and during venous cannulation. A blinded observer using a behavioral scale for rating pain in children performed assessments of behavior and pain before and following venous cannulation. Children who received 50% or 70% nitrous oxide were more likely to be relaxed, 59% and 84%, respectively, and had little evidence of pain. Of those given 100% oxygen or no mask, only 30% and 21%, respectively, were considered relaxed, and 16% and 15% had little evidence of pain during venous cannulation. Side effects were seen in 28% of the group given 70% nitrous oxide and included excitement, dysphoria, nausea, restlessness, and opisthotonic movements. Both 50% and 70% nitrous oxide in oxygen administered to pediatric patients are effective at decreasing the pain and anxiety associated with venous cannulation, but use of the latter is associated with side effects.

The study of the effect of analgesics in the newborn is difficult in the clinical situation and resort must be made to animals. Pethidine given within 1 hour of delivery is believed to cause less depression than when the time interval is longer. This study investigates whether it is pethidine or its metabolites which cause respiratory depression by comparing the respiratory effects of pethidine and its metabolites in the newborn rabbit. Fentanyl and buphrenorphine were also investigated as alternative analgesics. The response in the newborn rabbit to anoxia, is periods of dyspnoea, primary apnoea, and gasping. The metabolites of pethidine increased the primary apnoea signifying depression almost as much as pethidine. Depression was also produced when anoxia was induced 5 minutes after pethidine. Fentanyl caused less depression than pethidine or its metabolites excepting normeperidinic acid. Buphrenorphine administration resulted in the least depression with little difference between the low and high doses. Thus both pethidine and its metabolites are factors in the persisting depression, while buphrenorphine compared well with pethidine and fentanyl.

A basic tenet of economic theory is that production increases in total whenever factors of production specialize according to their comparative advantages. This very basic law of comparative advantage is not restricted in its application to merely the physical factors of production such as land. Labor, or human capital, is a factor of production, and thus total production is greater if individuals specialize according to their natural, or acquired, talents. Despite the fact that academics propound this law of comparative advantage, very little has been done to implement the law into faculty assignments. Rather, we find that most academic departments at universities require their faculty to not only teach, but also to perform research. This assignment policy occurs even though not all faculty have equal capabilities in both teaching and research. The authors criticize this tendency toward standardization of faculty, using the economic law of comparative advantage as the theoretical justification for their criticism.

guage. It is readily apparent that there are striking differences between language patterns used in school and language patterns used in disadvantaged homes. In contrast to the standardized, technically precise, and homogeneous language of education, the language of economic and cultural minorities is variable, non-technical, and highly heterogeneous (2). In cultural minorities, the range in language ability may run from monolingual in the minority tongue to monolingual in the national tongue, with the majority evidencing some degree of bilingualism between these two extremes.

To determine whether the gastric content pH of paediatric patients could be raised in an effort to decrease post-aspiration morbidity and mortality, the antacid sodium citrate (0.4 ml.kg-1) was given preoperatively to 25 patients aged 1 to 14 (6.0 +/- 3.5, mean +/- SD) years. Their gastric content pH was measured following induction of anaesthesia. These values were compared to those obtained from a control group (n = 20) ranging in age from seven months to nine (3.3 +/- 2.7) years. A gastric content pH value of greater than 2.5 was measured in 23 of the 25 patients who received sodium citrate. There were only two patients in the control group with a gastric content pH greater than 2.5, p less than 0.001, Fisher exact test. Only one child refused to take the medication. The administration of sodium citrate appears to be an effective method of raising the gastric content pH in paediatric patients.

Massive endobronchial hemorrhage due to balloon-tipped catheter rupture of a branch of the pulmonary artery in a fully heparinized patient undergoing cardiopulmonary bypass is potentially lethal. Death occurs due to asphyxiation. Endobronchial intubation (double-lumen endotracheal tube) appears to be a simple and effective method for control of the airway and tamponade of the bleeding site, which allows for completion of the surgical procedure until protamine sulphate reversal can be achieved.

THE human corpus luteum of pregnancy is cystic up to the fourth month of pregnancy. The fluid content of the luteal follicle may be as much as 1.5 c.c.