Energy conversion theorems for some linear steady states.

One of the main issues that real energy converters present, when they produce effective work, is the inevitable entropy production. Within the context of nonequilibrium thermodynamics, entropy production tends to energetically degrade human-made or living systems. On the other hand, it is not useful to think about designing an energy converter that works in the so-called minimum entropy production regime since the effective power output and efficiency are zero. In this paper we establish some energy conversion theorems similar to Prigogine's theorem with constrained forces. The purpose of these theorems is to reveal trade-offs between design and the so-called operation modes for (2×2)-linear isothermal energy converters. The objective functions that give rise to those thermodynamic constraints show stability. A two-mesh electric circuit was built as an example to demonstrate the theorems' validity. Likewise, we reveal a type of energetic hierarchy for power output, efficiency, and dissipation function when the circuit is tuned to any of the operating regimes studied here. These are maximum power output (MPO), maximum efficient power (MPη), maximum omega function (MΩ), maximum ecological function (MEF), maximum efficiency (Mη), and minimum dissipation function (mdf).

In and around the pineal gland: a neuroimaging review.

Lesions arising in or around the pineal gland comprise a heterogeneous group of pathologies ranging from benign non-neoplastic cysts to highly malignant neoplasms. Pineal cysts are frequently encountered as an incidental finding in daily radiology practice but there is no universal agreement on the criteria for, frequency of, and duration of follow-up imaging. Solid pineal neoplasms pose a diagnostic challenge owing to considerable overlap in their imaging characteristics, although a combination of radiological appearances, clinical findings, and tumour markers allows for narrowing of the differential diagnosis. In this review, we describe the radiological anatomy of the pineal region, clinical symptoms, imaging appearances, and differential diagnosis of lesions arising in this area, and highlight the clinical management of these conditions.

Transcriptomic analysis reveals pronounced changes in gene expression due to sub-lethal pyrethroid exposure and ageing in insecticide resistance Anopheles coluzzii.

BACKGROUND: Malaria control is heavily reliant on the use of insecticides that target and kill the adult female Anopheline vector. The intensive use of insecticides of the pyrethroid class has led to widespread resistance in mosquito populations. The intensity of pyrethroid resistance in some settings in Africa means mosquitoes can contact bednets treated with this insecticide class multiple times with minimal mortality effects. Furthermore, both ageing and diel cycle have been shown to have large impacts on the resistance phenotype. Together, these traits may affect other aspects of vector biology controlling the vectorial capacity or fitness of the mosquito. RESULTS: Here we show that sublethal exposure of a highly resistant Anopheles coluzzii population originally from Burkina Faso to the pyrethroid deltamethrin results in large and sustained changes to transcript expression. We identify five clear patterns in the data showing changes to transcripts relating to: DNA repair, respiration, translation, behaviour and oxioreductase processes. Further, we highlight differential regulation of transcripts from detoxification families previously linked with insecticide resistance, in addition to clear down-regulation of the oxidative phosphorylation pathway both indicative of changes in metabolism post-exposure. Finally, we show that both ageing and diel cycle have major effects on known insecticide resistance related transcripts. CONCLUSION: Sub-lethal pyrethroid exposure, ageing and the diel cycle results in large-scale changes in the transcriptome of the major malaria vector Anopheles coluzzii. Our data strongly supports further phenotypic studies on how transcriptional changes such as reduced expression of the oxidative phosphorylation pathway or pyrethroid induced changes to redox state might impact key mosquito traits, such as vectorial capacity and life history traits.

Diagnostic utility of cerebrospinal fluid analysis in dogs with suspected idiopathic epilepsy.

BACKGROUND: Idiopathic epilepsy (IE) is the most common cause of repeated seizures in dogs. The International Veterinary Epilepsy Task Force consensus guidelines recommend performing magnetic resonance imaging (MRI) of the brain and cerebrospinal fluid (CSF) analysis as part of a tier II diagnosis of IE, and these procedures have documented risks. The aim of this retrospective study was to identify how often dogs with suspected IE have abnormalities on CSF analysis. METHODS: Dogs aged between 6 months and 6 years that were presented with a history of two or more seizures with at least 24 h between seizure episodes, a normal neurologic examination, no evidence of toxic or metabolic causes, a normal MRI scan (including contrast administration) and CSF analysis were included. RESULTS: Eighty-two dogs were included. Of these, nine dogs (10.9%) had abnormalities on CSF analysis: five of nine dogs (55.5%) had albuminocytologic dissociation, three of nine dogs (33.3%) had mild increases in total nucleated cell count (TNCC), and one of nine dogs (11.1%) had mild increase in both total protein and TNCC. Cytology in dogs with elevated TNCC revealed a mononuclear pleocytosis. One of the nine dogs with abnormal CSF had a seizure within the 24 h before investigations, and six of nine dogs had a seizure within 1 month before investigation. CONCLUSION: CSF analysis can play an important role in the diagnostic investigation of the underlying causes of repeated seizures. However, in dogs with a normal inter-ictal neurological examination and MRI scan, it rarely reveals significant abnormalities, and the risk of performing a CSF tap may outweigh the potential diagnostic gain.

Use of acupuncture as adjuvant analgesic technique in dogs undergoing thoracolumbar hemilaminectomy.

The aim of this study was to investigate the analgesic efficacy of a preoperative acupuncture treatment in 24 client-owned dogs undergoing thoracolumbar hemilaminectomy. Dogs were randomly assigned to either group A (Acupuncture) or group C (Control). Before skin incision, group A was treated with acupuncture, performed under general anaesthesia for 30 min. Rescue intraoperative fentanyl was administered following a 20% increase in cardiovascular parameters compared to baseline values, measured before incision. An observer masked to the treatment assessed pain, pre- and postoperatively, with the Glasgow (GCPS), the Colorado (CPS) pain scales and a Visual Analogue Scale (VAS); additionally, the mechanical thresholds (MT) were measured with the Electronic von Frey Anaesthesiometer (EVF) at four points located near the herniated disc. The groups were compared with respect to intraoperative cardiovascular and respiratory variables, rescue fentanyl administered in total and at different surgical events (first incision [FI], drilling [DR], disc removal [RE] and skin suturing [ST]), and pre- and postoperative pain scores and MT. Group A received less fentanyl than group C (P = 0.014); this difference was significant at FI P = 0.035) and RE (P = 0.004). The improvement in postoperative CPS score (P = 0.013), VAS score (P = 0.003) and MT (P = 0.001) compared to preoperative values was greater for group A than for group C, whereas the treatment assignment had no effect on postoperative changes in GCPS compared to baseline. Pre-operative acupuncture may help improving perioperative analgesia in dogs with intervertebral disc herniation undergoing thoracolumbar hemilaminectomy.

RHDV2 epidemic in UK pet rabbits. Part 2: PCR results and correlation with vaccination status.

OBJECTIVE: To report PCR results and vaccination status of rabbits with rabbit haemorrhagic disease following an investigation into sudden or unexpected death. MATERIALS AND METHODS: PCR testing for RHDV2 and RHDV1 was performed on rabbit liver samples at two laboratories. Laboratory A reported results as positive or negative; Laboratory B reported results quantitatively as RNA copies per mg liver, categorised as negative, inconclusive or positive. The vaccination status of rabbits with both histopathological features of rabbit haemorrhagic disease and positive PCR test results were collated. RESULTS: PCR results matched histopathological findings in 188 of 195 (96%) cases. Seven individuals showed equivocal results, all of which had histopathological features of RHD but three tested PCR-negative and four results conflicted between laboratories. RHDV2 was the serotype detected in all PCR-positive cases. Histological features of rabbit haemorrhagic disease and PCR test results were positive in 125 rabbits; 51 unvaccinated, 56 in-date with Nobivac Myxo-RHD and 13 vaccinated against RHDV2 - although nine of these were vaccinated within 10 days of death. CLINICAL SIGNIFICANCE: PCR testing complements histopathology in cases of sudden death in rabbits by confirming the diagnosis and identifying virus serotype, but there can be false negatives. Although RHDV2 is currently prevalent in UK pet rabbits, vaccination against both RHDV1 and RHDV2 is recommended. Failures of RHDV2 vaccine are infrequent.

RHDV2 epidemic in UK pet rabbits. Part 1: clinical features, gross post mortem and histopathological findings.

OBJECTIVES: To report clinical features, gross post mortem and histopathological findings from an investigation into sudden or unexpected death in rabbits that was undertaken during an outbreak of rabbit haemorrhagic disease. MATERIALS AND METHODS: Using a standard protocol, veterinarians were invited to submit case histories and results of their post mortem examination of pet rabbits that died unexpectedly. Histopathological examination of heart, lungs, liver, spleen and kidney samples was collated with macroscopic appearance and clinical details. RESULTS: Hepatocellular necrosis, characteristic of rabbit haemorrhagic disease, was observed in 185 of 300 (62%) submissions, often accompanied by glomerular thrombosis and changes in other organs. Evidence of rabbit haemorrhagic disease was not apparent on histopathology in 113 of 300 (38%) rabbits. Gross post mortem examination by veterinary practitioners did not always reflect reported histopathological changes. No macroscopic abnormalities were seen in 78/185 (42%) of rabbit haemorrhagic disease cases. Rapid death and death of other rabbits in the household were common features of rabbit haemorrhagic disease. Ante mortem clinical signs included anorexia, collapse, lethargy, seizures, icterus, bleeding from the mouth, dyspnoea, hypothermia, pyrexia, bradycardia or poor blood clotting. CLINICAL IMPORTANCE: Rabbit haemorrhagic disease can be suspected from a history of sudden death, especially if multiple rabbits are affected. There is not always macroscopic evidence of the disease but histopathology is useful to support or refute a diagnosis of rabbit haemorrhagic disease and provide information about other causes of death.

Economic Impact of Implementing Malnutrition Screening and Nutritional Management in Older Adults in General Practice.

OBJECTIVES: Malnutrition is a common and significant public health problem, especially for older adults, as the consequences are costly. National guidelines (NICE CG32/QS24) highlight the need to identify and manage malnutrition, the implementation of which was deemed "high impact to produce cost savings". The 'Malnutrition Pathway', endorsed by NICE and other professional bodies, is a practical evidence-based guide to help community healthcare professionals (HCP) to implement guidance on malnutrition management. Published evaluations of its use are needed. DESIGN: This service evaluation in older adults assessed the impact of implementing the 'Malnutrition Pathway' on health care use and costs, as well as the acceptability of the management strategies and effect on malnutrition risk. SETTING: 5 GP surgeries in Gloucestershire. PARTICIPANTS: 163 older adults (80±9 years) with a range of primary diagnoses, living in their own home, were screened using the Malnutrition Universal Screening Tool ('MUST') (n50 low risk (LR); n41 medium risk (MR); n72 high risk (HR)). All patients were managed according to risk (LR: no further management; MR: dietary advice (DA); and HR: DA plus two oral nutritional supplements (ONS) (1 serve 300kcal, 18g protein; 125ml). MEASUREMENTS: At each review (6weeks, 3 and 6 months), 'MUST' score, compliance and satisfaction to their management plan were recorded. Healthcare use was collected from GP records 6 months before and after implementation of the pathway. A simple cost analysis was completed. RESULTS: Implementing appropriate management of malnutrition led to significant reductions in hospital admissions (p=0.028), length of hospital stay (p=0.05), GP visits (p=0.007) and antibiotic prescriptions (p=0.05). Over 6 months, the costs to manage malnutrition (HCP time, ONS) were more than offset by the savings associated with these reductions in health care use (per patient savings of -£395.64 MR+HR; -£997.02 HR). The proportion of individuals at risk of malnutrition reduced over time, and patients reported being satisfied with the DA (97%) and ONS (96%), consuming 90% of their ONS prescription. CONCLUSION: Managing malnutrition significantly reduces healthcare use, with a positive budget impact, in older malnourished patients in primary care. This represents an opportunity to improve patient care with benefit on health care spend.

Molecular patterns of response and treatment failure after frontline venetoclax combinations in older patients with AML.

The BCL-2 inhibitor venetoclax combined with hypomethylating agents or low-dose cytarabine represents an important new therapy for older or unfit patients with acute myeloid leukemia (AML). We analyzed 81 patients receiving these venetoclax-based combinations to identify molecular correlates of durable remission, response followed by relapse (adaptive resistance), or refractory disease (primary resistance). High response rates and durable remissions were typically associated with NPM1 or IDH2 mutations, with prolonged molecular remissions prevalent for NPM1 mutations. Primary and adaptive resistance to venetoclax-based combinations was most commonly characterized by acquisition or enrichment of clones activating signaling pathways such as FLT3 or RAS or biallelically perturbing TP53. Single-cell studies highlighted the polyclonal nature of intratumoral resistance mechanisms in some cases. Among cases that were primary refractory, we identified heterogeneous and sometimes divergent interval changes in leukemic clones within a single cycle of therapy, highlighting the dynamic and rapid occurrence of therapeutic selection in AML. In functional studies, FLT3 internal tandem duplication gain or TP53 loss conferred cross-resistance to both venetoclax and cytotoxic-based therapies. Collectively, we highlight molecular determinants of outcome with clinical relevance to patients with AML receiving venetoclax-based combination therapies.

Implementing a guideline for acute tonsillitis using an ambulatory medical unit.

OBJECTIVE: Acute tonsillitis represents a significant proportion of admissions to ENT departments nationally. Given current hospital pressures, it is vital to look for safe alternatives to admission. This study explores the safe management of patients in an ambulatory medical unit, without the need for admission. METHODS: A retrospective review of 48 patients' notes was carried out. Following the development and implementation of a guideline for acute tonsillitis, a prospective re-audit of 41 patients was carried out, measuring length of stay, overnight admissions and re-admissions. RESULTS: The rate of overnight admission following implementation of the guideline fell from 0.75 to 0.29, and average length of stay dropped from 19.2 to 9.5 hours. There were two re-admissions in each cycle of the audit, which represents a non-significant increase. CONCLUSION: The tonsillitis guideline has significantly reduced admissions and length of stay. Re-admissions remain low, demonstrating that this is a safe and cost-effective intervention.

Systematic Review of Evidence Pertaining to Factors That Modify Risk of Early Childhood Caries.

INTRODUCTION: A systematic review of evidence on the impact of modifiable risk factors on early childhood caries (ECC) was conducted to inform recommendations in a World Health Organization manual on ECC prevention. OBJECTIVES: To systematically review published evidence pertaining to the effect of modifiable risk factors on ECC. METHODS: Twelve questions relating to infant feeding, diet, oral hygiene, and fluoride were addressed, as prioritized by a World Health Organization expert panel. Questions pertaining to the use of fluoride toothpaste were excluded due to its proven efficacy. The target population was children aged <72 mo. Data sources included Medline, Embase, CINAHL, and PubMed, and all human epidemiologic studies were included. The highest level of evidence was used for evidence synthesis and, where possible, meta-analysis. The review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement, with evidence assessed via the GRADE method. RESULTS: Of the 13,831 papers identified, 627 were screened in duplicate; of these, 139 were included. The highest-level evidence indicated that breastfeeding ≤24 mo does not increase ECC risk but suggested that longer-duration breastfeeding increases risk (low-quality evidence). Low-quality evidence indicated increased risk associated with consumption of sugars in bottles. Only 1 study had data on the impact of sugars in complementary foods, which increased risk. Moderate-quality evidence showed a benefit of oral health education for caregivers (odds ratio, 0.39; 95% CI, 0.19 to 0.80, P = 0.009). Meta-analysis of data on the impact on ECC from living in a fluoridated area showed a significant effect (mean difference, -1.25; 95% CI, -1.24 to -0.36; P = 0.006). Limited moderate- and low-quality data indicated a benefit of fluoride exposure from salt and milk, respectively. CONCLUSION: The best available evidence indicates that breastfeeding up to 2 y of age does not increase ECC risk. Providing access to fluoridated water and educating caregivers are justified approaches to ECC prevention. Limiting sugars in bottles and complementary foods should be part of this education. KNOWLEDGE TRANSFER STATEMENT: This research is being used by the World Health Organization in developing a toolkit on the prevention and management of early childhood caries. The information will guide 1) governments in developing national oral health plans and 2) clinicians when providing preventive advice, including that regarding infant feeding practices. It will help ensure that advice is in line with current World Health Organization guidelines and the best available evidence.

'Hiding their troubles': a qualitative exploration of suicide in Bhutanese refugees in the USA.

BACKGROUND: Suicide is a major global health concern. Bhutanese refugees resettled in the USA are disproportionately affected by suicide, yet little research has been conducted to identify factors contributing to this vulnerability. This study aims to investigate the issue of suicide of Bhutanese refugee communities via an in-depth qualitative, social-ecological approach. METHODS: Focus groups were conducted with 83 Bhutanese refugees (adults and children), to explore the perceived causes, and risk and protective factors for suicide, at individual, family, community, and societal levels. Audio recordings were translated and transcribed, and inductive thematic analysis conducted. RESULTS: Themes identified can be situated across all levels of the social-ecological model. Individual thoughts, feelings, and behaviors are only fully understood when considering past experiences, and stressors at other levels of an individual's social ecology. Shifting dynamics and conflict within the family are pervasive and challenging. Within the community, there is a high prevalence of suicide, yet major barriers to communicating with others about distress and suicidality. At the societal level, difficulties relating to acculturation, citizenship, employment and finances, language, and literacy are influential. Two themes cut across several levels of the ecosystem: loss; and isolation, exclusion, and loneliness. CONCLUSIONS: This study extends on existing research and highlights the necessity for future intervention models of suicide to move beyond an individual focus, and consider factors at all levels of refugees' social-ecology. Simply focusing treatment at the individual level is not sufficient. Researchers and practitioners should strive for community-driven, culturally relevant, socio-ecological approaches for prevention and treatment.

Equal North: how can we reduce health inequalities in the North of England? A prioritization exercise with researchers, policymakers and practitioners.

BACKGROUND: The Equal North network was developed to take forward the implications of the Due North report of the Independent Inquiry into Health Equity. The aim of this exercise was to identify how to reduce health inequalities in the north of England. METHODS: Workshops (15 groups) and a Delphi survey (3 rounds, 368 members) were used to consult expert opinion and achieve consensus. Round 1 answered open questions around priorities for action; Round 2 used a 5-point Likert scale to rate items; Round 3 responses were re-rated alongside a median response to each item. In total, 10 workshops were conducted after the Delphi survey to triangulate the data. RESULTS: In Round 1, responses from 253 participants generated 39 items used in Round 2 (rated by 144 participants). Results from Round 3 (76 participants) indicate that poverty/implications of austerity (4.87 m, IQR 0) remained the priority issue, with long-term unemployment (4.8 m, IQR 0) and mental health (4.7 m, IQR 1) second and third priorities. Workshop 3 did not diverge from findings in Round 1. CONCLUSIONS: Practice professionals and academics agreed that reducing health inequalities in the North of England requires prioritizing research that tackles structural determinants concerning poverty, the implications of austerity measures and unemployment.

Synthesis and thermoluminescence of erbium-activated lithium niobate.

Erbium-activated lithium niobate; 1, 2, and 4 mol% (LN-1, LN-2 and LN-4 respectively) were synthesized by solid-state method and their thermoluminescent (TL) properties were analyzed. The glow curve of LN-4 showed a maximum at 177 °C and its linear dose-response interval ranged from 50 to 350 Gy. Its TL intensity was two orders of magnitude greater compared to those of pure lithium niobate (LN), LN-1 and LN-2. We conclude that LN-4 is an interesting material for TL dosimetry applications.

Ecological efficiency of finite-time thermodynamics: A molecular dynamics study.

We present a molecular dynamics simulation of a two-dimensional Carnot engine. The optimization of this engine is achieved through the velocity of the piston, allowing not only the optimization of power output but also some other figures of merit involving entropy production. The maximum power and maximum ecological efficiencies are computed. It is shown that the near ideal gas working substance displays an endoreversible Carnot-like engine behavior. This can be considered as a prove of the validity of the Carnot-like endoreversible model. An effective reversible cycle different than the Carnot one is obtained, in agreement with the endoreversible hypothesis flexibility. We compare the efficiencies stemming from an ideal gas approximation with those of the simulation, and then we propose a suitable approximation to an endoreversible heat engine and to a reversible Joule-Brayton cycle which fits very well to the simulation results. Finally, we show that the maximum ecological efficiency η=1-τ^{3/4}, which is also very close to the upper bound of the low-dissipation heat engine under maximum ecological (and Omega) conditions, is close for describing the dynamics of the simulated cycle under maximum power and maximum ecological conditions in the so-named heat engine operability region.

Translation, adaptation, and pilot of a guided self-help intervention to reduce psychological distress in South Sudanese refugees in Uganda.

BACKGROUND: In this period of unprecedented levels of displacement, scalable interventions are needed to address mental health concerns of forced migrants in low-resource settings. This paper describes the adaptation and piloting of a guided, multi-media, self-help intervention, Self-Help Plus (SH+), which was developed to reduce psychological distress in large groups of people affected by adversity. METHODS: Using a phased approach that included community consultations, cognitive interviewing, facilitator training, pilot implementation, and a qualitative process evaluation, we adapted SH+ for use among South Sudanese refugees in a refugee settlement in northern Uganda. RESULTS: The SH+ materials, including audio-recorded sessions and an accompanying illustrated manual, were translated into Juba Arabic. Cognitive interviewing primarily resulted in adaptations to language with some minor adaptations to content. Facilitator training and supervision led to further suggested changes to delivery methods. An uncontrolled pilot study (n = 65) identified changes in the expected direction on measures of psychological distress, functional impairment, depression, wellbeing, and psychological flexibility. The process evaluation resulted in further adaptations to intervention materials and the decision to focus future effectiveness evaluations of the intervention in its current form on South Sudanese female refugees. CONCLUSIONS: We found that this potentially scalable, guided self-help intervention could be adapted for and feasibly implemented among female South Sudanese refugees in northern Uganda. These findings lay the groundwork for a future rigorous evaluation of SH+ in this context.

Self Help Plus: study protocol for a cluster-randomised controlled trial of guided self-help with South Sudanese refugee women in Uganda.

BACKGROUND: Exposure to armed conflict and forced displacement constitute significant risks for mental health. Existing evidence-based psychological interventions have limitations for scaling-up in low-resource humanitarian settings. The WHO has developed a guided self-help intervention, Self Help Plus (SH+), which is brief, implemented by non-specialists, and designed to be delivered to people with and without specific mental disorders. This paper outlines the study protocol for an evaluation of the SH+ intervention in northern Uganda, with South Sudanese refugee women. METHODS: A two-arm, single-blind cluster-randomised controlled trial will be conducted in 14 villages in Rhino Camp refugee settlement, with at least 588 women experiencing psychological distress. Villages will be randomly assigned to receive either SH+ with enhanced usual care (EUC), or EUC alone. SH+ is a five-session guided self-help intervention delivered in workshops with audio-recorded materials and accompanying pictorial guide. The primary outcome is reduction in overall psychological distress over time, with 3 months post-treatment as the primary end-point. Secondary outcomes are self-defined psychosocial concerns, depression and post-traumatic stress disorder symptoms, hazardous alcohol use, feelings of anger, interethnic relations, psychological flexibility, functional impairment and subjective wellbeing. Psychological flexibility is a hypothesised mediator, and past trauma history and intervention attendance will be explored as potential moderators. DISCUSSION: This trial will provide important information on the effectiveness of a scalable, guided self-help intervention for improving psychological health and wellbeing among people affected by adversity. TRIAL REGISTRATION: ISRCTN50148022; registered 13/03/2017.

Afterglow dosimetry performance of beta particle irradiated lithium zirconate.

In this work, we report for the very first time on the thermoluminescence (TL) and afterglow (AG) properties of Li2ZrO3. The ternary oxide Li2ZrO3 was synthesized by solid state reaction of a mixture of Li2CO3 and ZrO2 subjected to thermal annealing at 400°C for 2h and 1000°C during 24h in air. The characteristic glow curves of beta particle irradiated samples exhibit an intense TL emission located around 150°C. From the shape of the TL curve, a 0.4 form factor was determined, suggesting that first order kinetics processes are involved. The afterglow decay curves were recorded after exposure to beta particle irradiation in the dose range from 0.5 up to 2kGy. The AG integrated in the time interval from 510 to 600s after radiation exposure shows a linear dependence as a function of the irradiation dose from 0.5 up to 256Gy. A method is proposed to compute the lower detection limit and the AG sensitivity and applied to the studied phosphors. Structural and morphological characterization were carried out by X-ray diffraction and Scanning Electron Microscopy, respectively. From the results presented, it is concluded that the AG response of the synthesized Li2ZrO3 presents features suitable to develop radiation detectors and dosimeters.

Organophosphate flame retardants in dust collected from United States fire stations.

Firefighters are exposed to chemicals during fire events and we previously demonstrated that fire station dust has high levels of polybrominated diphenyl ethers (PBDEs). In conducting the Fire Station Dust Study, we sought to further characterize the chemicals to which firefighters could be exposed - measuring the emerging class of phosphorous-containing flame retardants (PFRs) in fire stations, for the first time, as well as PBDEs. Dust samples from 26 fire stations in five states were collected from vacuum-cleaner bags and analyzed for PFRs and PBDEs. PFR concentrations were found to be on the same order of magnitude as PBDE concentrations (maximum PFR: 218,000ng/g; maximum PBDE: 351,000ng/g). Median concentrations of tri-n-butyl phosphate (TNBP), tris (2-chloroisopropyl) phosphate (TCIPP), and tris(1,3-dichloroisopropyl)phosphate (TDCIPP) in dust from fire stations were higher than those previously reported in homes and other occupational settings around the world. Total PFR levels did not vary significantly among states. Levels of TDCIPP were higher in stations where vacuum cleaners were used to clean surfaces other than the floor. PBDE levels were comparable to those found in our previous study of 20 California fire stations and much higher than levels in California residences. PFR and PBDE levels in fire station dust are higher than in other occupational and residential settings, underscoring the need to identify and control sources of this contamination.