Evaluation of Mass Sensitive Micro-Array biosensors for their feasibility in multiplex detection of low molecular weight toxins using mycotoxins as model compounds

Mycotoxins produced by Fusarium species including trichothecenes, zearalenone and fumonisins, can co-contaminate food and feed throughout the supply chain, including cereal grains and animal feeds. There is an increasing demand to enhance global food security by improving the monitoring of mycotoxins throughout our food supply chain. For time and cost-efficient analysis, rapid tests capable of detecting multiple toxins from a single sample are ideal. Considering these current trends in mycotoxin testing, this project examined the feasibility of using both a portable and non-portable mass-based biosensor for multiplex mycotoxin detection. The biosensor was a mass sensitive microarray (MSMA) which consisted of 4 × 16 miniaturized mass sensitive transducer pixels based on solidly mounted resonator (SMR) technology. Functionalisation of individual pixels on the sensor surface using nano-spotting technology for the simultaneous and semi-quantitative detection of three regulated mycotoxins: T2-toxin (T2) zearalenone (ZEN), and fumonisin B1 (FumB1) was examined. With the integration of portable and non-portable microfluidic devices for antibody and standard sample injections, competitive inhibition assays were developed followed by singleplex and multiplex calibration curves. The characteristics and performance of the MSMA were evaluated including sensitivity which was determined as the concentration causing 50% inhibition. Sensitivity of singleplex assays using the portable microfluidic device (PMD) were 1.3 ng/ml, 2.0 ng/ml and 6.8 ng/ml for T2, FumB1 and ZEN, respectively. Sensitivity of the multiplex assay again using the PMD was 6.1 ng/ml, 3.6 ng/ml and 2.4 ng/ml for T2, FumB1 and ZEN, respectively. The PMD was an easy to use and highly sensitive screening tool which has been demonstrated for the multiplex detection of three regulated mycotoxins. Analysis was in real time and results were fully digital. Since detection of analytes was by mass it was both a label-free and cost-efficient method proposed method of analysis for mycotoxins.

The end user sensor tree: An end-user friendly sensor database

Detailed knowledge regarding sensor based technologies for the detection of food contamination often remains concealed within scientific journals or divided between numerous commercial kits which prevents optimal connectivity between companies and end-users. To overcome this barrier The End user Sensor Tree (TEST) has been developed. TEST is a comprehensive, interactive platform including over 900 sensor based methods, retrieved from the scientific literature and commercial market, for aquatic-toxins, mycotoxins, pesticides and microorganism detection. Key analytical parameters are recorded in excel files while a novel classification system is used which provides, tailor-made, experts' feedback using an online decision tree and database introduced here. Additionally, a critical comparison of reviewed sensors is presented alongside a global perspective on research pioneers and commercially available products. The lack of commercial uptake of the academically popular electrochemical and nanomaterial based sensors, as well as multiplexing platforms became very apparent and reasons for this anomaly are discussed.

A land use regression model for explaining spatial variation in air pollution levels using a wind sector based approach

Estimating pollutant concentrations at a local and regional scale is essential in environmental and health policy decision making. Here we present a novel land use regression (LUR) modelling methodology that exploits the high temporal resolution of fixed-site monitoring (FSM) to produce a national-scale air quality model for the key pollutant NO₂. The methodology partitions concentration time series from a national FSM network into wind-dependent sectors or "wedges". A LUR model is derived using predictor variables calculated within the directional wind sectors, and compared against the long-term average concentrations within each sector. Validation results, based on 15 FSM training sites, show that the model captured 78% of the spatial variability in NO₂ across the Republic of Ireland. This compares favourably to traditional LUR models based on purpose-designed monitoring campaigns despite using approximately half the number of monitoring points. Results also demonstrate the value of incorporating the relative position of emission source and receptor into the empirical LUR model structure. We applied the model at a high-resolution across the Republic of Ireland to enable applications such as the study of environmental exposure and human health, assessing representativeness of air quality monitoring networks and informing environmental management and policy makers. While the study focuses on Ireland, the methodology also has potential applicability for other criteria pollutants where appropriate FSM and meteorological networks exist.

Erratum: Observation of the hyperfine spectrum of antihydrogen

This corrects the article DOI: 10.1038/nature23446.

Observation of the hyperfine spectrum of antihydrogen

The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers and the measurement of the zero-field ground-state splitting at the level of seven parts in 10¹³ are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron, inspired Schwinger's relativistic theory of quantum electrodynamics and gave rise to the hydrogen maser, which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter. Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 10⁴. This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.

Antihydrogen accumulation for fundamental symmetry tests

Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles.

Antihydrogen studies are important in testing the fundamental principles of physics but producing antihydrogen in large amounts is challenging. Here the authors demonstrate an efficient and high-precision method for trapping and stacking antihydrogen by using controlled plasma.

Targeted temperature management in cardiovascular disease complicated by cardiac arrest

PURPOSE

The majority of cardiac arrests occur due to cardiovascular etiology. Targeted temperature management (TTM) (32-34 °C) is a part of the standard post arrest care. We hypothesized that lower body temperature may lead to reduced cardiac metabolic demand and potentially have a beneficial effect on myocardial function.

METHODS

We performed a retrospective study on patients admitted to the intensive care unit following cardiac arrest secondary to cardiovascular etiology over a 9 year period. We assessed the impact of TTM on neurological and cardiac outcomes.

RESULTS

There were 57 patients in the cohort; 21 patients in the TTM group and 36 in the non-TTM group. Demographic characteristics were similar in both groups-the majority of patients (86 vs 80 %, respectively) were males in their 60s. Neurological outcomes were similar; 24 % of patients died during the ICU admission in the TTM group vs 18 % in the non-TTM group. Mean GCS on admission to the ICU was 4 vs 7, respectively, and 11 at discharge in both groups. Majority of patients recovered good neurological function (GCS ≥ 13)-57 % in the TTM group vs 64 % in the non-TTM group. The change in left ventricular function over a 6 month follow up period was significantly better in patients who received targeted temperature management-mean change of +4.4 vs -3.3 %, respectively. This proved to be statistically significant (p = 0.02).

CONCLUSIONS

The study demonstrates a possible beneficial effect of TTM on long-term cardiac function, when instituted following cardiac arrest.

Investigation of effect of particle size and rumen fluid addition on specific methane yields of high lignocellulose grass silage

This work examines the digestion of advanced growth stage grass silage. Two variables were investigated: particle size (greater than 3 cm and less than 1cm) and rumen fluid addition. Batch studies indicated particle size and rumen fluid addition had little effect on specific methane yields (SMYs). In continuous digestion of 3 cm silage the SMY was 342 and 343 L CH4 kg(-1)VS, respectively, with and without rumen fluid addition. However, digester operation was significantly affected through silage floating on the liquor surface and its entanglement in the mixing system. Digestion of 1cm silage with no rumen fluid addition struggled; volatile fatty acid concentrations rose and SMYs dropped. The best case was 1cm silage with rumen fluid addition, offering higher SMYs of 371 L CH4 kg(-1)VS and stable operation throughout. Thus, physical and biological treatments benefited continuous digestion of high fibre grass silage.

Comparison of specific methane yield of perennial ryegrass prepared by thermal drying versus non-thermal drying in small-scale batch digestion tests

Dried milled biomass samples are frequently utilised in small-scale batch digestion tests. However, herbage chemical composition can be altered by thermal drying, and this may affect specific methane (CH4) yields. Thus, the specific CH4 yield of herbage pre- and post-ensiling, prepared by two preparation methods were compared. Perennial ryegrass samples were either non-thermally dried (i.e. subject to cryogenic conditions, -196 °C) or thermally dried (40 °C), prior to milling. Specific CH4 yield was subsequently determined in a small-scale batch digestion test. Herbage pre-ensiling yielded 204 and 243 L CH4 kg(-1)VS(added) and herbage post-ensiling yielded 212 and 188 L CH4 kg(-1)VS(added) with non-thermal dried and thermal dried sample preparation methods, respectively. Due to opposing effects of thermal drying on CH4 yields of herbage either pre- or post-ensiling, it is not recommended to use thermal drying. Instead, it is recommended that non-thermal dried herbage samples are used in small-scale batch digestion tests.

An experimental limit on the charge of antihydrogen

The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects.

Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus

Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

Description and first application of a new technique to measure the gravitational mass of antihydrogen

Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe a novel direct test methodology; we search for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap. In the absence of systematic errors, we can reject ratios of the gravitational to inertial mass of antihydrogen >75 at a statistical significance level of 5%; worst-case systematic errors increase the minimum rejection ratio to 110. A similar search places somewhat tighter bounds on a negative gravitational mass, that is, on antigravity. This methodology, coupled with ongoing experimental improvements, should allow us to bound the ratio within the more interesting near equivalence regime.

Resonant quantum transitions in trapped antihydrogen atoms

The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and--by comparison with measurements on its antimatter counterpart, antihydrogen--the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves.

Disengaging from acute inpatient psychiatric care: a description of service users' experiences and views

The growing number of people worldwide with mental health problems is increasing and making intensive demands on existing services. Recent reorganizations of healthcare provision in the UK have focused predominantly on administrative efficiency, standardization and cost-effectiveness. Although little evidence exists that reorganizations, per se, directly result in improved health nationally, nevertheless, organizational change coupled with improved care provision can have a considerable impact on the mental health of people. It is known that service users want person-centred help with improving their confidence, autonomy and cognitive and social skills so as to be able to manage their lives within the social context in which they live. In this study, semi-structured interviews were used to explore service users' expectations and experiences of acute inpatient care and the early post-discharge period. While the social environment of the wards was seen by many as conducive to promoting safety and interpersonal relationships, others found the experience lacking in assisting them to resume their lives post discharge. If acute care is to become more than a mechanism for addressing and containing risk, better targeted interventions are required to help individuals find strategies that are transferable to the context of their 'real' lives. A number of factors that were identified by respondents in this study are identified and discussed.

Centrifugal separation and equilibration dynamics in an electron-antiproton plasma

Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.

Autoresonant excitation of antiproton plasmas

We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.

Evaporative cooling of antiprotons to cryogenic temperatures

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

Health professionals' attitudes to depot injection antipsychotic medication: a systematic review

Healthcare professionals are key providers of information about antipsychotic medication and may have a significant influence on the decisions that service users make about how their medication is delivered. This systematic review aimed to explore health professionals' attitudes and beliefs towards antipsychotic depot medication. A systematic search of AMED, BNI, CINAHL, EMBASE, HEALTH BUSINESS ELITE, HMIC, MEDLINE and PsycINFO was carried out, as well as hand searches of journals and citation searches. Studies were selected if the terms 'attitudes/beliefs' and 'depot/injection' were included in the title or abstract, if health professionals were participants in the study and if original data were included. The search strategy produced 131 papers. Eight relevant studies were then selected for the review. They included six cross-sectional surveys and two qualitative studies. It was shown that the research carried out is still very sparse. Depots are seen as old fashioned, stigmatizing, causingside effects and being costly, and they are often not prescribed because of a presumed adherence to oral medication. More research needs to be carried out to further explore these issues, to look at the role of non-medical prescribers and explore the relationship between health professionals' attitudes and those of service users.

Psychiatric wards: places of safety?

In recent years, the purpose and quality of provision delivered in acute inpatient psychiatric settings have been increasingly questioned. Studies from a service user perspective have reported that while some psychiatric inpatients feel safe and cared for, others feel their time in hospital is neither safe nor therapeutic. This paper explores the experiences of service users on acute inpatient psychiatric wards in England, with a particular focus on their feelings of safety and security. Interviews were conducted with 60 psychiatric inpatients in England. The majority of service users felt safe in hospital and felt supported by staff and other service users. However, anything that threatened their sense of security such as aggression, bullying, theft, racism and the use of alcohol and drugs on the ward, made some respondents feel insecure and unsafe. Psychiatric wards are still perceived by many as volatile environments, where service users feel forced to devise personal security strategies in order to protect themselves and their property. It would appear that there remains much to do before research findings and policies are implemented in ways that facilitate all service users to derive the maximum benefit from their inpatient experience.

Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector

A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton extractions is compared to that of electrons and positrons.

Survey of psychiatrists' views of nurse prescribing

For mental health nurses and service users to realize the benefits of non-medical prescribing, psychiatrists need to understand the remit of this role and be actively involved in influencing it. Although healthcare policy in the UK supports the expansion of non-medical prescribing, it requires much more for the successful implementation of such initiatives in practice. The aim of this survey was to explore the attitudes of all grades of psychiatrist working in two mental health trusts in the West Midlands to nurse prescribing. A specifically designed questionnaire was sent out to two groups of psychiatrists to assess their attitudes towards non-medical prescribing. Psychiatrists (n = 147) completed and returned a specifically designed questionnaire of their views. The more senior doctors appeared less concerned about nurse prescribing. Junior doctors expressed equivocation towards the role, suggesting that nurse prescribers be consistently supervised and have limited access to mental health drugs. The findings from this study have considerable implications for teams if junior doctors hold different views to their senior colleagues. Without the assistance of trusts in facilitating role change, the introduction of new roles could potentially heighten conflict between professions.

Compression of antiproton clouds for antihydrogen trapping

Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

The role of the nurse prescriber: the views of mental health and non-mental health nurses

Even though the introduction of the role of the nurse prescriber promises improved access to medicines and increased flexibility in the workforce, the take-up of this role to date has been variable across the UK. This questionnaire-based study sought to compare the expectations of two distinct groups of nurses, one from a mental health and the other from a non-mental health background prior to becoming prescribers. Non-mental health nurses were of the opinion that being able to prescribe would increase efficiency and maximize resources, while mental health nurses saw prescribing primarily in terms of the benefits to clients--increased choice, improved access to care, better information about treatments and better quality of care.

Design of surface electrode array for electromyography in the genioglossus muscle

The patency of the upper airway is dependent on the sustained activity of upper airway muscles, in particular the genioglossus (GG) muscles which act to protrude the tongue. Obstructive sleep apnea syndrome (OSAS) is a common and serious disorder in which this mechanism fails, resulting in frequent collapse of the airway during sleep. The properties of the upper airway muscles are therefore of interest in both normal and OSAS subjects, so that their role in the pathogenesis of OSAS can be better understood. Electromyography (EMG) is an important tool for assessing muscle activity and has been used in many GG studies. We have designed a new appliance incorporating a surface electrode array for GG EMG recording. The electrode configuration enables estimation of muscle fibre conduction velocity (CV), an important parameter for monitoring muscle fatigue, which has not been studied before in the GG. The appliance is also designed to provide accurate and repeatable placement of electrodes. Preliminary results presented demonstrate the performance of our appliance, which will now be used to measure GG CV in a range of fatiguing conditions.

Antimatter plasmas in a multipole trap for antihydrogen

We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage lifetimes of antiproton and positron plasmas in the combined Penning-neutral trap, and compared these to lifetimes without the neutral trap fields. The magnetic well depth was 0.6 T, deep enough to trap ground state antihydrogen atoms of up to about 0.4 K in temperature. We have demonstrated that both particle species can be stored for times long enough to permit antihydrogen production and trapping studies.

Aspects of the relationship between doctors and depressed patients that enhance satisfaction with primary care

Depression will be the second most common threat to health by the end of the next decade. The incidence of depression in primary care is already high. This has serious implications for the types of services available, the range of personnel who deliver them and the extent to which patients are helped by the treatments provided. Research reveals that approximately two-thirds of patients with depression are treated with medication, although it is not known how effective medication is in the long term. It would appear that the relationship between the patient and prescriber is a highly significant factor in determining whether or not patients adhere to treatment regimens and to what extent they improve. This study used a qualitative approach to identify how patients treated with medication for their depression perceived the relationship with their prescribing clinician, what kinds of information and advice they received and what they wanted. Several aspects of the helpful relationship are identified, such as the characteristics and behaviour of the clinician, as well as the way in which information is imparted. The frequency of monitoring consultations and patients' perceptions of their importance were also examined. The issue of stigma, particularly self-stigma and what can be done to prevent it, is discussed. The paper concludes with suggestions for improving the quality of primary care for patients' prescribed medication for depression, and especially for making maximum use of the initial consultation. The main implication for mental health nurses is that central to all interventions for depression is the primacy of the relationship, without which, clients' belief in treatment is diminished.

A comparison of the work and values of community mental health nurses in two mental health NHS Trusts

With the reconfiguration of health services in both the primary and secondary sectors, the role of community mental health nurses (CMHNs) has become a highly contested one within mental health care. There would be great variability in the skills that CMHNs possess, the contexts in which they work and the nature of the work they do. This study sought to explore aspects of the work of those nurses who provide services at the interface between policy and practice. Two groups of CMHNs were compared, one working in an urban setting (Trust A) and the other in a rural (Trust B), focusing particularly on caseloads and client mix, the values held by CMHNs, the models of care they utilize and what they consider would improve care in the future. A specially designed 39-item questionnaire was employed, with a mix of open and closed questions, and statements to which participants were asked to respond on a three-point Likert scale. The findings raised interesting issues around collaborative working, whether CMHNs are happy to take on clients previously on their caseload, bureaucratization, autonomy, role definition within a culture of working with primary care, lack of specific models utilized by CMHNs, and the demand for greater training and educational support. The implications of the study are discussed with the aim of assisting mental health nurses determine their future roles.

The effects of bipolar electrode montage on conduction velocity estimation from the surface electromyogram

This study examines the influence of the bipolar electrode montage on conduction velocity (CV) estimation. Electrode montage refers to the combination of two parameters, the inter-electrode distance (IED), the distance between the two electrodes of a bipolar pair, and the inter-signal distance (ISD), the distance between two bipolar signals used to calculate CV. Data from the biceps brachii (BB) and tibialis anterior (TA) of healthy subjects are analysed. Two approaches are used for CV estimation. The first returns a single value per epoch. The second is based on finding velocity values from individual peaks in the signal and results in a peak velocity (PV) distribution being generated per epoch. It is concluded that CV estimation is significantly dependent on the choice of the (IED, ISD) electrode montage. The main results are that the electrode montage affects (1) the mean PV and CV estimates, (typically P < 0.001), (2) the degree of spatial variability, and (3) the width of the PV distributions. The combination of a small IED and large an ISD is recommended.

Intranasal corticosteroid therapy for obstructive sleep apnoea in patients with co-existing rhinitis

BACKGROUND

Increased nasal airflow resistance (NAR) may contribute to the pathophysiology of obstructive sleep apnoea syndrome (OSAS) but studies investigating the effects of relieving nasal obstruction in OSAS have produced differing results. There are no reports of intranasal corticosteroid therapy in adult OSAS patients with reversible nasal obstruction.

METHODS

We evaluated an intranasal corticosteroid, fluticasone propionate, in 24 consecutive snorers with associated rhinitis using a randomised, placebo controlled, crossover design. Patients underwent polysomnography, snoring noise, and NAR measurements at baseline and after each 4 week treatment period.

RESULTS

Twenty three patients completed the protocol and were divided into an apnoeic group (group A; 13 patients) and a non-apnoeic snoring group (group S; 10 patients) based on an apnoea-hypopnoea frequency (AHI) of > or =10/h or <10/h. AHI was significantly lower following treatment with fluticasone than with placebo in the total population (median (quartile range) 11.9 (22.6) v 20 (26.3); p<0.05) and in group A (23.3 (21.3) v 30.3 (31.9); p<0.05). Median (95% confidence interval) within subject differences for AHI were -3.2 (-17.7 to -0.2) in the total population and -6.5 (-29.5 to 1.8) in group A. NAR was also lower on fluticasone (2.74 (1.21) v 3.27 (1.38), p<0.01), within subject difference being -0.45 (95% CI -0.87 to -0.21). The changes in AHI and NAR in group A were significantly correlated (r=0.56; p<0.05). Snoring noise and sleep quality were unchanged but daily diary records indicated subjective improvements in nasal congestion and daytime alertness with fluticasone (p<0.02).

CONCLUSIONS

Intranasal fluticasone is of benefit to some patients with OSAS and rhinitis. The data suggest that this form of nasal obstruction may contribute to the pathophysiology of OSAS.

Suppression of genioglossus muscle tone and activity during reflex hypercapnic stimulation by GABA(A) mechanisms at the hypoglossal motor nucleus in vivo

The genioglossus muscle is involved in the maintenance of an open airway for effective breathing. Inhibitory neurotransmitters may be responsible for the major suppression of hypoglossal motor output to genioglossus muscle that occurs in certain behaviours such as rapid-eye-movement sleep. There is evidence for GABA(A) receptor-mediated inhibition of hypoglossal motoneurons in vitro. However, comparable studies have not been performed in vivo and the interactions of such mechanisms with integrative reflex respiratory control have also not been determined. Urethane-anaesthetised, tracheotomized and vagotomized rats were studied whilst diaphragm and genioglossus muscle activities, blood pressure and the electroencephalogram were recorded. Microdialysis probes were implanted into the hypoglossal motor nucleus, with sites verified by histology. Genioglossus responses to microdialysis perfusion of muscimol (GABA(A) agonist: 0, 0.1, 1 and 10 microM in artificial cerebrospinal fluid) were recorded at inspired CO(2)s of 0, 5 and 7.5% in six rats. Responses to bicuculline (GABA(A) antagonist, 0, 1, 10, 100 and 1000 microM) were also studied in six rats with and without CO(2) stimulation. Genioglossus activity decreased with muscimol (P<0.0001), with major suppression at 1 and 10 microM during air breathing (decreases=70.2% and 92.8%, P<0.005). Genioglossus activity increased with CO(2) (P=0.003), but genioglossus activation with 5 and 7.5% CO(2) were almost abolished with 10-microM muscimol. Responses were specific to genioglossus muscle as there were no changes in diaphragm, respiratory rate or blood pressure with muscimol (P>0.144). Antagonism of GABA(A) receptors increased genioglossus activity (P<0.001). These results show that GABA(A) receptor stimulation at the hypoglossal motor nucleus suppresses both genioglossus muscle tone and activity in the presence of reflex stimulation produced by hypercapnia. Recruitment of such mechanisms may contribute to the major suppression of genioglossus activity observed with and without CO(2) stimulation in behaviours such as rapid-eye-movement sleep.

The work and values of mental health nurses observed

While there is agreement among stakeholders that change is required in mental healthcare, yet the precise nature of this change and how it should be brought about are relatively under-explored. Research has looked at developments taking place in primary mental health services, but relatively little has examined the work of community mental health nurses (CMHNs), especially those working at the interface between primary and secondary care. This study used a 39-item questionnaire to explore how CMHNs perceive their role and the degree to which they are able to carry it out. The findings suggests that while CMHNs are enthusiastic about their work and are keen to see mental health services develop in primary care, many are concerned about how they are perceived by other health personnel, deficiencies in their therapeutic skills and the level of support they currently receive. The study concludes by suggesting areas that managers, commissioners and educators should target to enable CMHNs to continue to play their part in a service that relies heavily upon them.

Modulating effect of respiration on atrioventricular conduction time assessed using PR interval variation

Respiratory sinus arrhythmia (RSA) is the variation of heart rate (or RR interval) in phase with respiration and has been extensively studied. However, the effect of respiration on atrioventricular conduction delay (and hence PR interval length) has not yet received much attention. This work reports on measurements of respiration and associated RR and PR variability, in 11 subjects, assessed through surface electrocardiogram measurements, for both paced and spontaneous respiration in the supine position. A wavelet-based approach was used to extract RR and PR intervals. The accuracy of RR and PR interval measurement was consistent with previously published work. Respiratory atrioventricular conduction delay variability (RCV) was assessed using three techniques: spectral, peak-to-trough and cosinor methods. All measures showed statistically significant variations in PR interval due to respiration during paced respiration at 6 min(-1). Of the three measures, cosinor analysis was most reliable in highlighting RCV. Using this measure, statistically significant RCV was seen in ten out of the 11 subjects during paced respiration. The magnitude of the variability was estimated as +/- 5.9% of the mean PR interval. In spontaneous respiration, statistically significant RCV was seen in approximately half of the subjects, with an estimated variability of +/- 1.5%. As a control, statistically significant values for RSA were also obtained from the same data, which agreed with previously published measurements. It was concluded that respiration does indeed modulate atrioventricular conduction delay, deep breathing in the supine position accentuates this effect, and cosinor analysis provides a reliable means for quantifying this effect.

In search of the history of Irish psychiatric nursing

Based on a paper given at the Cinderella Services conference at South Bank University, London, in April 2001, this paper explores the origins and development of the asylum system in Ireland, and traces the relationship between the politics and practice of mental health care. The role of the attendants is illuminated in so far as the limited primary source material allows. Although some aspects of the history of Irish mental health services have been subject to scholarship, psychiatric nursing is an area that has not. In particular, very little attention has been paid to the role that attendants and asylum nurses played in the Irish asylum system, especially during the late nineteenth and early twentieth centuries. The government constructed an extensive network of asylums and workhouses to deal with the growing numbers of mentally disordered and impoverished people. Irish asylum nurses tended to come from rural stock, and have agricultural skills; they were able to communicate with patients in either English or Gaelic. They were encouraged to impart to patients skills that would permit them to find employment or contribute to the upkeep of the asylum.

UK and USA Clinical Mental Health Nurse Specialists' perceptions of their work

There is little scholarship to compare the work of mental health nurses in different countries, although this is perhaps understandable given that mental health nursing as a discrete discipline exists only in a few countries worldwide. The small-scale study reported here sought to compare the perceptions of UK and American Clinical Nurse Specialists of various aspects of their work, including latest professional developments, current therapies and interventions, and the major problems confronting nurses today. Prior to the main study being undertaken, a short questionnaire was piloted in both countries. The main questionnaire was distributed to 34 American nurses and completed by 25 (75.5% response rate), and to 28 UK nurses and completed by 24 (86% response rate). Descriptive statistics and content analyses were used to analyse the data which suggested that where UK nurses were concerned with the range and availability of services for clients and their families, American nurses were primarily preoccupied with the quality of those services. The American sample placed greater emphasis on the provision of care that enabled clients to take responsibility for themselves than did their UK counterparts. While acknowledging the limitations of the study, the results would appear to suggest that American nurses tend to favour humanistic care, have a belief in the efficacy of chemotherapy and aim to get people functioning independently. They fear the threat to their relationship with clients that managed care might entail. Concurrently, UK nurses appear to be preoccupied with finding appropriate services for their clients and they appear to believe that the changing nature of their work is designed to accommodate structural changes in the health service, rather than to meet the needs of clients. The implications of these findings are discussed.

Electromyogram median frequency, spectral compression and muscle fibre conduction velocity during sustained sub-maximal contraction of the brachioradialis muscle

Changes in the median frequency of the power spectrum of the surface electromyogram (EMG) are commonly used to detect muscle fatigue. Previous research has indicated that changes in the median frequency are related to decreases in muscle fibre conduction velocity (MFCV) during sustained fatiguing contractions. However, in experimental studies the median frequency has been consistently observed to decrease by a relatively greater amount than MFCV. In this paper, a new estimate of EMG frequency compression, the Spectral Compression Estimate (SCE), is compared with the median frequency of the EMG power spectrum, the median frequency of the EMG amplitude spectrum and MFCV measured during sustained, isometric, fatiguing contractions of the brachioradialis muscle at 30, 50 and 80% maximum voluntary contraction (MVC). The SCE is found to provide a better estimate of the observed changes in MFCV than the median frequency of either the EMG power spectrum or EMG amplitude spectrum.

Mental health work observed: a comparison of the perceptions of psychiatrists and mental health nurses

This study explores mental health nurses' and psychiatrists' perceptions of their work. It was carried out in five mental health Trusts in the West Midlands, UK. Three groups were surveyed: psychiatrists, hospital-based nurses and community mental health nurses (CMHNs). Results showed that CMHNs' sources of job satisfaction and dissatisfaction were more similar to those of psychiatrists than to those of their hospital-based counterparts. All three groups cited the intrinsic worthwhileness of their work, autonomy, the scope for creativity, the variety their job offered and their contact with clients as contributing to their overall job satisfaction. Hospital-based nurses listed the support they received from colleagues as their second source of job satisfaction, whereas CMHNs and psychiatrists cited the provision of care to patients. Excessive administrative duties and the absence of or poor quality of management were perceived by all three groups as sources for dissatisfaction with their work. Hospital nurses cited job insecurity as a principal concern more frequently than CMHNs and psychiatrists. The paper concludes by discussing recommendations for changes to improve the nature of the work in mental health services and in the work environment. Changes must reflect the concerns of the different groups of mental health professionals.

The language of mental health nursing reports: firing paper bullets?

A great deal of the caring work of nursing is accomplished and mediated through language. This paper attempts to characterize some of this language in quantitative and stylistic terms in an attempt to characterize the genre of nursing report language. Nursing students (n = 26) and graduate nurses (n = 3) viewed a videotape of a person being interviewed by a psychiatrist and produced written reports. These showed a large proportion of words relating to the person and to feelings and needs, compared to existing databases of the English language in general. The language produced by the participants also contained many modal or modifying words and is similar to spoken rather than written English in terms of the proportion of lexical content. There was much diversity in their descriptions and the vocabulary used to refer to the client. Graduate nurses showed more scepticism of the evidence provided by the video and advocated more investigation and questioning of the client. The use of standard forms and techniques of expression suggests that these reports were assembled on a language production line. Finally, we advocate a more systematic approach to educating nursing students about the power of the language they use.