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Microbial communities at the airway mucosal barrier are conserved and highly ordered, in likelihood reflecting co-evolution with human host factors. Freed of selection to digest nutrients, the airway microbiome underpins cognate management of mucosal immunity and pathogen resistance. We show here the initial results of systematic culture and whole-genome sequencing of the thoracic airway bacteria, identifying 52 novel species amongst 126 organisms that constitute 75% of commensals typically present in heathy individuals. Clinically relevant genes encode antimicrobial synthesis, adhesion and biofilm formation, immune modulation, iron utilisation, nitrous oxide (NO) metabolism and sphingolipid signalling. Using whole-genome content we identify dysbiotic features that may influence asthma and chronic obstructive pulmonary disease. We match isolate gene content to transcripts and metabolites expressed late in airway epithelial differentiation, identifying pathways to sustain host interactions with microbiota. Our results provide a systematic basis for decrypting interactions between commensals, pathogens, and mucosa in lung diseases of global significance.
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Bacterias , Membrana Mucosa , Humanos , Membrana Mucosa/microbiología , Bacterias/genética , Simbiosis , Inmunidad Mucosa , GenómicaRESUMEN
This report describes the development of a water-tolerant green catalyst for benzyl bromination. The catalyst, indium chloride, exhibits high catalytic activity with a variety of toluene derivatives in continuous flow. Good yields (59-77%) were obtained in all the cases. Improved selectivity was observed under flow conditions, when compared to batch operation.
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Halogenación , Tolueno , Indio , AguaRESUMEN
We audited use of acute hospital beds in Connolly Hospital over a 3-month period (January-March 2020) which coincided with increased provision of step-down (nursing home) beds. Our results show both ineffective and inefficient baseline uses of these acute beds. Increased step-down beds improve patient care by reducing the trolley count, shortening average length of stay and reducing waiting lists. These data confirm that more step-down beds are a high priority for our Health Service to improve the effectiveness and efficiency of our hospitals i.e. better care at less cost.
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Hospitales , Alta del Paciente , Humanos , Casas de Salud , Listas de Espera , Tiempo de Internación , Ocupación de CamasRESUMEN
COVID-19 and a low vitamin D state share common risk factors, which might explain why vitamin D deficiency has been linked with higher COVID-19 mortality. Moreover, measures of serum vitamin D may become lower during systemic inflammatory responses, further confounding the association via reverse causality. In this prospective study (recruited over 12 months), we examined whether the association between a low vitamin D state and in-hospital mortality due to SARS-CoV-2 pneumonia in unvaccinated subjects is explained by (i) the presence of shared risk factors (e.g., obesity, advanced age) or (ii) a reduction in serum 25(OH)D due to COVID-19 (i.e., reverse causality). In this cohort of 232 (mean age = 56 years) patients (all had SARS-CoV-2 diagnosed via PCR AND required supplemental oxygen therapy), we failed to find an association between serum vitamin D and levels of CRP, or other inflammatory markers. However, the hazard ratio for mortality for subjects over 70 years of age (13.2) and for subjects with a serum 25(OH)D level less than 30 nmol·L−1 (4.6) remained significantly elevated even after adjustment for gender, obesity and the presence of diabetes mellitus. Subjects <70 years and >70 years had significantly higher mortality with a serum 25(OH)D less than 30 nmol·L−1 (11.8% and 55%), than with a serum 25(OH)D greater than 30 nmol·L−1 (2.2% and 25%). Unvaccinated Caucasian adults with a low vitamin D state have higher mortality due to SARS CoV-2 pneumonia, which is not explained by confounders and is not closely linked with elevated serum CRP.
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COVID-19 , Deficiencia de Vitamina D , Adulto , Anciano , Anciano de 80 o más Años , Humanos , Persona de Mediana Edad , Obesidad , Estudios Prospectivos , SARS-CoV-2 , Vitamina D , VitaminasRESUMEN
INTRODUCTION: Our hospital found itself at the epicentre of the Irish COVID-19 pandemic. We describe the organisational challenges faced in managing the surge and identified risk factors for mortality and ICU admission among hospitalised SARS-CoV-2-infected patients. METHODS: All hospitalised SARS-CoV-2 patients diagnosed between March 13 and May 1, 2020, were included. Demographic, referral, deprivation, ethnicity and clinical data were recorded. Multivariable regression, including age-adjusted hazard ratios (HR (95% CI), was used to explore risk factors associated with adverse outcomes. RESULTS: Of 257 inpatients, 174 were discharged (68%) and 39 died (15%) in hospital. Two hundred three (79%) patients presented from the community, 34 (13%) from care homes and 20 (8%) were existing inpatients. Forty-five percent of community patients were of a non-Irish White or Black, Asian or minority ethnic (BAME) population, including 34 Roma (13%) compared to 3% of care home and 5% of existing inpatients, (p < 0.001). Twenty-two patients were healthcare workers (9%). Of 31 patients (12%) requiring ICU admission, 18 were discharged (58%) and 7 died (23%). Being overweight/obese HR (95% CI) 3.09 (1.32, 7.23), p = 0.009; a care home resident 2.68 (1.24, 5.6), p = 0.012; socioeconomically deprived 1.05 (1.01, 1.09), p = 0.012; and older 1.04 (1.01, 1.06), p = 0.002 were significantly associated with death. Non-Irish White or BAME were not significantly associated with death 1.31 (0.28, 6.22), p = 0.63 but were significantly associated with ICU admission 4.38 (1.38, 14.2), p = 0.014 as was being overweight/obese 2.37 (1.37, 6.83), p = 0.01. CONCLUSION: The COVID-19 pandemic posed unprecedented organisational issues for our hospital resulting in the greatest surge in ICU capacity above baseline of any Irish hospital. Being overweight/obese, a care home resident, socioeconomically deprived and older were significantly associated with death, while ethnicity and being overweight/obese were significantly associated with ICU admission.
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COVID-19 , SARS-CoV-2 , COVID-19/mortalidad , Femenino , Mortalidad Hospitalaria , Hospitalización , Hospitales , Humanos , Irlanda , Masculino , Pandemias , Factores de RiesgoRESUMEN
INTRODUCTION: Coronavirus disease 2019 (COVID-19), is a respiratory illness caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Clinical Blood Sciences Laboratory (CBSL) plays a key role in supporting the monitoring and management of patients with COVID-19 disease. OBJECTIVE: To provide a comprehensive CBSL testing protocol to support the medical management of SARS-CoV-2 infection. METHODS: Description of the biochemical, haematological and immunological tests that have a role in the assessment and monitoring of patients with COVID-19 infection. RESULTS: We provide a test menu for clinical laboratories to ensure the effective monitoring, management and prognostication of COVID-19 patients in hospital. CONCLUSION: Given the rapidity with which patients with COVID-19 disease can deteriorate, we recommend regular testing with vigilance paid to the rate and trajectory of change in each of these parameters.
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Betacoronavirus , Técnicas de Laboratorio Clínico , Infecciones por Coronavirus/diagnóstico , Neumonía Viral/diagnóstico , Adulto , COVID-19 , Prueba de COVID-19 , Femenino , Humanos , Pandemias , SARS-CoV-2RESUMEN
Neuralgic Amyotrophy (NA) or Parsonage-Turner syndrome is an idiopathic neuropathy commonly affecting the brachial plexus. Associated phrenic nerve involvement, though recognised, is thought to be very rare. We present a case series of four patients (all male, mean age 53) presenting with dyspnoea preceded by severe self-limiting upper limb and shoulder pain, with an elevated hemi-diaphragm on clinical examination and chest X-ray. Neurological examination of the upper limb at the time of presentation was normal. Diaphragmatic fluoroscopy confirmed unilateral diaphragmatic paralysis. Pulmonary function testing demonstrated characteristic reduction in forced vital capacity between supine and sitting position (mean 50%, range 42-65% predicted, mean change 23%, range 22-46%), reduced maximal inspiratory pressures (mean 61%, range 43-86% predicted), reduced sniff nasal inspiratory pressure (mean 88.25, range 66-109 cm H2O) and preserved maximal expiratory pressure (mean 107%, range 83-130% predicted). Phrenic nerve conduction studies confirmed phrenic nerve palsy. All patients were managed conservatively. Follow-up ranged from 6 months to 3 years. Symptoms and lung function variables normalised in three patients and improved significantly in the fourth. The classic history of severe ipsilateral shoulder and upper limb neuromuscular pain should be elicited and thus NA considered in the differential for a unilateral diaphragmatic paralysis, even in the absence of neurological signs. Parsonage-Turner syndrome is likely to represent a significantly under-diagnosed aetiology of phrenic nerve palsy. Conservative management as opposed to surgical intervention is advocated as most patients demonstrate gradual resolution over time in this case series.
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Neuritis del Plexo Braquial/complicaciones , Neuritis del Plexo Braquial/diagnóstico , Enfermedades del Sistema Nervioso Periférico/etiología , Nervio Frénico , Parálisis Respiratoria/etiología , Neuritis del Plexo Braquial/terapia , Disnea/etiología , Humanos , Masculino , Persona de Mediana Edad , Dolor Musculoesquelético/etiología , Conducción Nerviosa , Parálisis Respiratoria/terapia , Dolor de Hombro/etiología , Extremidad SuperiorRESUMEN
In the elderly, asthma remains a clinical challenge. Recognition, diagnosis and treatment are all complex. Influenced by processes, such as aging, the identification of an 'asthma microbiome' presents a further challenge. This editorial discusses aging and the 'asthma microbiome' separately and then evaluates their potential relationship. Current evidence suggests that differences in the airway microbiome are associated with asthma, however, whether such associations are comparable or different for late-onset disease is yet to be established. Microbes are now linked to fundamental physiological processes, such as aging, based on data from invertebrate systems. This will likely confer implications for asthma in the elderly, and it is crucial that such emerging scientific data are considered in the context of aging, asthma and late-onset disease.
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Envejecimiento , Asma/microbiología , Microbiota , Sistema Respiratorio/microbiología , Factores de Edad , Anciano , Animales , Antiasmáticos/uso terapéutico , Asma/diagnóstico , Asma/tratamiento farmacológico , Asma/inmunología , Asma/fisiopatología , Interacciones Huésped-Patógeno , Humanos , Inmunidad Mucosa , Persona de Mediana Edad , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/microbiología , Sistema Respiratorio/efectos de los fármacos , Sistema Respiratorio/inmunología , Sistema Respiratorio/fisiopatología , Factores de RiesgoRESUMEN
BACKGROUND: The acute consumption of dietary nitrate has been shown to improve exercise capacity in athletes, healthy adults and subjects with peripheral vascular disease. Many COPD patients have reduced exercise capacity. We hypothesized that acute nitrate consumption might increase incremental shuttle walk test (ISWT) distance in COPD subjects. METHODS: Eleven COPD subjects were randomly assigned to consume either a high nitrate or a matched, low nitrate beverage in a double-blind, randomized, placebo-controlled, crossover design. ISWT distance was measured both before and 3 h after the beverage and change was recorded. After a 7-day washout, ISWT distances were re-measured before and 3 h after the alternate beverage and changes were recorded. RESULTS: We observed an increase in ISWT distance after consuming the high nitrate juice (25 m) compared with a reduction after the low nitrate juice (14 m) (p < 0.01). This improvement in exercise capacity was associated with significant increases in serum nitrate (p < 0.000005) and nitrite (p < 0.01) levels and a significant lowering of resting blood pressure (<0.05). CONCLUSIONS: In patients with stable COPD, the acute consumption of dietary nitrate increased serum nitrate/nitrite levels and exercise capacity and was associated with a decrease in resting blood pressure. Nitrate consumption might alter exercise capacity in COPD patients.
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Nitratos/administración & dosificación , Enfermedad Pulmonar Obstructiva Crónica/dietoterapia , Anciano , Anciano de 80 o más Años , Presión Sanguínea/efectos de los fármacos , Estudios Cruzados , Método Doble Ciego , Prueba de Esfuerzo/efectos de los fármacos , Femenino , Hemodinámica/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Nitratos/sangre , Óxido Nítrico/sangre , Nitritos/sangre , Enfermedad Pulmonar Obstructiva Crónica/sangre , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , CaminataRESUMEN
BACKGROUND: A growing body of knowledge exists to guide efforts to improve the organisation and delivery of health care, most of which is based on work carried out in hospitals. It is uncertain how transferable this knowledge is to primary care. AIM: To understand the enablers and constraints to implementing a large-scale quality improvement programme in general practice, designed to improve care for people with chronic obstructive pulmonary disease. DESIGN AND SETTING: A qualitative study of 189 general practices in a socioeconomically and ethnically-mixed, urban area in east London, UK. METHOD: Twelve semi-structured interviews were conducted with people leading the programme and 17 in-depth interviews with those participating in it. Participants were local health system leaders, clinicians, and managers. A theoretical framework derived from evidence-based guidance for improvement programmes was used to interpret the findings. A complex improvement intervention took place with social and technical elements including training and mentorship, guidance, analytical tools, and data feedback. RESULTS: Practice staff wanted to participate in and learn from well-designed collaborative improvement projects. Nevertheless, there were limitations in the capacities and capabilities of the workforce to undertake systematic improvement, significant problems with access to and the quality of data, and tensions between the narrative-based generalist orientation of many primary care clinicians and the quantitative single-disease orientation that has characterised much of the quality improvement movement to date. CONCLUSION: Improvement guidance derived largely from hospital-based studies is, for the most part, applicable to improvement efforts in primary care settings, although large-scale change in general practice presents some particular challenges. These need to be better understood and addressed if improvement initiatives are to be effective.
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Medicina General/organización & administración , Atención Primaria de Salud/organización & administración , Enfermedad Pulmonar Obstructiva Crónica/terapia , Mejoramiento de la Calidad/organización & administración , Humanos , Londres/epidemiología , Evaluación de Programas y Proyectos de Salud , Investigación CualitativaRESUMEN
BACKGROUND: Post-traumatic seizures (PTS) is a well-known sequela of traumatic brain injury (TBI). The risk factors for PTS are still controversial. Studies on PTS in China are rare and no large prospective, multicenter-based studies are available. METHODS: Data were collected from 15 hospitals prospectively using standardized structured questionnaires in Shandong, a province in China with a follow-up of 2 years. RESULTS: A total of 3093 traumatic brain injury patients were validated and entered in this analysis. After 6 months of follow-up, 181 (59.9%) patients were identified as having PTS. The number were 236 (78.1%) and 302 after 1 year and 2 years' follow-up, respectively. The cumulative 24-month-rate of PTS is 9.8%. Among these 302 patients, 242 were male (80.1%) and 60 female (19.9%). A marked peak was seen in the young people group aged 15-24 (27.8%). Three factors were identified as significant in the multivariate model of PTS: Frontal-temporal lobar contusion, Linear fracture and Severity of TBI measured by initial Glasgow Coma Scale (GCS). CONCLUSION: This prospective cohort study shows the epidemiologic features and risk factors of PTS in China. Frontal-temporal lobar contusion, linear fracture and severity of TBI measured by initial Glasgow Coma Scale (GCS) are risk factors for PTS. It is essential to establish a standard surveillance system for PTS.
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Lesiones Encefálicas/diagnóstico , Lesiones Encefálicas/epidemiología , Convulsiones/diagnóstico , Convulsiones/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , China/epidemiología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Lactante , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Adulto JovenRESUMEN
BACKGROUND: Aerosolized therapeutics hold great potential for effective treatment of various diseases including lung cancer. In this context, there is an urgent need to develop novel nanocarriers suitable for drug delivery by nebulization. To address this need, we synthesized and characterized a biocompatible drug delivery vehicle following surface coating of Fe3O4 magnetic nanoparticles (MNPs) with a polymer poly(lactic-co-glycolic acid) (PLGA). The polymeric shell of these engineered nanoparticles was loaded with a potential anti-cancer drug quercetin and their suitability for targeting lung cancer cells via nebulization was evaluated. RESULTS: Average particle size of the developed MNPs and PLGA-MNPs as measured by electron microscopy was 9.6 and 53.2 nm, whereas their hydrodynamic swelling as determined using dynamic light scattering was 54.3 nm and 293.4 nm respectively. Utilizing a series of standardized biological tests incorporating a cell-based automated image acquisition and analysis procedure in combination with real-time impedance sensing, we confirmed that the developed MNP-based nanocarrier system was biocompatible, as no cytotoxicity was observed when up to 100 µg/ml PLGA-MNP was applied to the cultured human lung epithelial cells. Moreover, the PLGA-MNP preparation was well-tolerated in vivo in mice when applied intranasally as measured by glutathione and IL-6 secretion assays after 1, 4, or 7 days post-treatment. To imitate aerosol formation for drug delivery to the lungs, we applied quercitin loaded PLGA-MNPs to the human lung carcinoma cell line A549 following a single round of nebulization. The drug-loaded PLGA-MNPs significantly reduced the number of viable A549 cells, which was comparable when applied either by nebulization or by direct pipetting. CONCLUSION: We have developed a magnetic core-shell nanoparticle-based nanocarrier system and evaluated the feasibility of its drug delivery capability via aerosol administration. This study has implications for targeted delivery of therapeutics and poorly soluble medicinal compounds via inhalation route.
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Sistemas de Liberación de Medicamentos/métodos , Magnetismo , Nanopartículas/química , Quercetina/farmacología , Aerosoles , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Femenino , Glutatión/análisis , Humanos , Interleucina-6/análisis , Ácido Láctico/química , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica de Transmisión , Tamaño de la Partícula , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polímeros/químicaRESUMEN
Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape. The need to validate each NP for safety and efficacy with each therapeutic compound or combination of therapeutics is an enormous challenge, which forces industry to focus mainly on those nanoparticle materials where data on safety and efficacy already exists, i.e., predominantly polymer NPs. However, the enhanced functionality affordable by inclusion of metallic materials as part of nanoengineered particles provides a wealth of new opportunity for innovation and new, more effective, and safer therapeutics for applications such as cancer and cardiovascular diseases, which require selective targeting of the therapeutic to maximize effectiveness while avoiding adverse effects on non-target tissues.
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Portadores de Fármacos/química , Nanopartículas/química , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/terapia , Medios de Contraste , Stents Liberadores de Fármacos , Humanos , Nanopartículas/uso terapéutico , Neoplasias/tratamiento farmacológico , Polímeros/químicaRESUMEN
BACKGROUND: Asthma exacerbations remain a major unmet clinical need. The difficulty in obtaining airway tissue and bronchoalveolar lavage samples during exacerbations has greatly hampered study of naturally occurring exacerbations. This study was conducted to determine if mRNA profiling of peripheral blood mononuclear cells (PBMCs) could provide information on the systemic molecular pathways involved during asthma exacerbations. METHODOLOGY/PRINCIPAL FINDINGS: Over the course of one year, gene expression levels during stable asthma, exacerbation, and two weeks after an exacerbation were compared using oligonucleotide arrays. For each of 118 subjects who experienced at least one asthma exacerbation, the gene expression patterns in a sample of peripheral blood mononuclear cells collected during an exacerbation episode were compared to patterns observed in multiple samples from the same subject collected during quiescent asthma. Analysis of covariance identified genes whose levels of expression changed during exacerbations and returned to quiescent levels by two weeks. Heterogeneity among visits in expression profiles was examined using K-means clustering. Three distinct exacerbation-associated gene expression signatures were identified. One signature indicated that, even among patients without symptoms of respiratory infection, genes of innate immunity were activated. Antigen-independent T cell activation mediated by IL15 was also indicated by this signature. A second signature revealed strong evidence of lymphocyte activation through antigen receptors and subsequent downstream events of adaptive immunity. The number of genes identified in the third signature was too few to draw conclusions on the mechanisms driving those exacerbations. CONCLUSIONS/SIGNIFICANCE: This study has shown that analysis of PBMCs reveals systemic changes accompanying asthma exacerbation and has laid the foundation for future comparative studies using PBMCs.
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Asma/sangre , Asma/metabolismo , Transducción de Señal/fisiología , Adulto , Asma/genética , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Leucocitos Mononucleares/metabolismo , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Análisis de Componente Principal , Transducción de Señal/genéticaRESUMEN
BACKGROUND: A rich microbial environment in infancy protects against asthma [1], [2] and infections precipitate asthma exacerbations [3]. We compared the airway microbiota at three levels in adult patients with asthma, the related condition of COPD, and controls. We also studied bronchial lavage from asthmatic children and controls. PRINCIPAL FINDINGS: We identified 5,054 16S rRNA bacterial sequences from 43 subjects, detecting >70% of species present. The bronchial tree was not sterile, and contained a mean of 2,000 bacterial genomes per cm(2) surface sampled. Pathogenic Proteobacteria, particularly Haemophilus spp., were much more frequent in bronchi of adult asthmatics or patients with COPD than controls. We found similar highly significant increases in Proteobacteria in asthmatic children. Conversely, Bacteroidetes, particularly Prevotella spp., were more frequent in controls than adult or child asthmatics or COPD patients. SIGNIFICANCE: The results show the bronchial tree to contain a characteristic microbiota, and suggest that this microbiota is disturbed in asthmatic airways.
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Asma/microbiología , Bacterias/aislamiento & purificación , Adolescente , Adulto , Bacterias/clasificación , Bacterias/genética , Líquido del Lavado Bronquioalveolar , Estudios de Casos y Controles , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , ARN Ribosómico 16S/genética , Especificidad de la Especie , Adulto JovenRESUMEN
We report on the development of a novel optical oxygen sensor for breath monitoring applications using the technique of phase fluorometry. The principal design criteria are that the system be compact, lightweight, and employ a disposable sensing element (while performing competitively with current commercial analyzers). The oxygen-sensitive, luminescent ruthenium complex Ru[dpp](3)(2+) is encapsulated in a sol-gel matrix and deposited onto a custom-designed, polymer sensor chip that provides significantly improved luminescence capture efficiency. The performance of the sensor module is characterized using a commercially available lung simulator. A resolution of 0.03% O(2) is achieved, which compares well with commercial breath monitoring systems and, when combined with its immunity to humidity and ability to respond effectively across a broad range of breathing rates, makes this device an extremely promising candidate for the development of a practical, low-cost biodiagnostic tool.
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Pruebas Respiratorias/instrumentación , Mediciones Luminiscentes/instrumentación , Consumo de Oxígeno/fisiología , Oxígeno/análisis , Pruebas de Función Respiratoria/instrumentación , Transductores , Pruebas Respiratorias/métodos , Humanos , Mediciones Luminiscentes/métodos , Miniaturización , Reproducibilidad de los Resultados , Pruebas de Función Respiratoria/métodos , Sensibilidad y EspecificidadRESUMEN
This study focuses on the optimisation and characterisation of novel, ORganically MOdified SILicate (ORMOSIL)-based, hybrid sensor films for use in the detection of O(2) on a breath-by-breath basis in human health monitoring applications. The sensing principle is based on the luminescence quenching of the O(2)-sensitive ruthenium complex [Ru(ii)-tris(4,7-diphenyl-1,10-phenanthroline)], which has been entrapped in a porous sol-gel film. The detection method employed is that of phase fluorometry using blue LED excitation and photodiode detection. Candidate sensor films include those based on the organosilicon precursors, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane and phenyltriethoxysilane. While it has been established previously by the authors that these films exhibit a stable, highly sensitive response to O(2), this study focuses on selecting the material most suited for use in a breath monitor, based on the sensitivity, response time and humidity sensitivity of these films. Key parameters to be optimised include the O(2) sensitivity of the film and the film polarity, i.e. the degree of hydrophobicity. These parameters are directly linked to the precursors used. In this study a n-propyltriethoxysilane-derived O(2) sensor platform was selected as the optimum material for in-breath O(2) analysis due to its short response time, negligible humidity interference and suitable O(2) sensitivity in the relevant range in addition to its compatibility with a single-point calibration strategy.
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Oxígeno/análisis , Pruebas Respiratorias/instrumentación , Pruebas Respiratorias/métodos , Diseño de Equipo , Tecnología de Fibra Óptica , Humanos , Mediciones LuminiscentesRESUMEN
This paper describes the development of a generic platform for enhanced, integrated optic sensors based on fluorescence detection. The platform employs a novel optical configuration in order to achieve enhanced performance and has inherent multianalyte detection capability. The sensor element comprises a multimode ridge waveguide that has been patterned with an analyte-sensitive fluorescent spot, which is excited directly using a LED. The platform was applied to the detection of gaseous oxygen as a proof of principle. The sol-gel-derived sensor spots were doped with an oxygen-sensitive fluorescent dichlororuthenium dye complex and intensity-based calibration data were generated from the oxygen-dependent waveguide output. The sensor achieved a LOD of 0.62% and a resolution of less than 0.96% gaseous oxygen, which compares favourably with a similar, recently reported system. This device highlights the combination of inexpensive rapid prototyping techniques and a dedicated sensor enhancement strategy that together facilitate the production of an effective prototype sensor platform.