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1.
Sci Total Environ ; 861: 160639, 2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36470388

RESUMO

The detection and attribution of methane in aquifers overlying oil and gas reservoirs has recently gained increasing attention internationally. The Surat Basin, in the Great Artesian Basin (GAB), Australia, hosts a coal seam gas (CSG) reservoir, with feedlots, town water supply, mines and agriculture that extract groundwater from aquifers that underly and overly the gas reservoir. This study aimed to use a multi-isotopic approach to differentiate biogenic methane generated in situ in GAB aquifers and the Condamine Alluvium, from the biogenic CSG produced from the underlying Walloon Coal Measures reservoir, to understand if gas had migrated or not. Dissolved methane (0.001 to 160 mg/l) and total methane concentrations (up to 91,818 ppmv) were measured using closed sampling methods and were higher than from open direct fill sampling (<0.001 to 25.4 mg/l), especially in gassy bores that contain dissolved methane above 10 to 13 mg/l. The CSG production waters and a gassy overlying aquifer bore had the most depleted water isotopes, and also the most enriched δ13C-DIC indicating strong methanogenesis. The majority of aquifers have isotopic signatures (δ13C-DIC, CH4 and CO2) indicating in situ methane production by primary CO2 reduction or fermentation, distinct from secondary microbial CO2 reduction in the CSG reservoir. Fractionation factors support methane production mainly via CO2 reduction, with fermentation in a subset of aquifer samples. The gas wetness parameters (636 to 20,000) are consistent with mainly microbial gases, with low dissolved ethane (max 0.04 mg/l). The majority of aquifer and alluvium samples in this study are consistent with in situ methane production, not migration, however in several gassy bores the methane source could not be clearly identified. This study is broadly applicable to understanding methane sources in aquifers overlying CSG reservoirs.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Metano/análise , Dióxido de Carbono , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Gases , Campos de Petróleo e Gás , Carvão Mineral
2.
J Psychosom Res ; 149: 110587, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34390941

RESUMO

OBJECTIVE: Most current Misophonia scales are not validated, do not include both emotional and physiological responses to triggers, and/or focus only on auditory triggers. This research aimed to develop and validate a measure of the magnitude of the Misophonic response that addressed these omissions. METHOD: Three studies were carried out with individuals with self-diagnosed Misophonia. In study 1, expert opinion and participants commented on initial items to determine both face and content validity. In study 2, scale structure, reliability, and convergent and discriminant validity were determined using correlations, principal component analysis (PCA), and reliability analysis. In study 3, factor structure was confirmed in another sample of participants using confirmatory factor analysis (CFA). RESULTS: The final 22-item scale assesses the magnitude of responses to triggers across any sensory modality. There are three subscales (emotional, physiological, and participation in life), with three additional items measuring frequency of triggers, avoidance of triggers, and time taken to recover from the triggers. The final scale showed suitable discriminant and convergent validity, with good internal consistency (Cronbach's alphas range 0.77 to 0.89). The three-component solution extracted using PCA explained 53.97% of variance, with all items loading between 0.45 and 0.84. The structure was confirmed with CFA (χ2 = 269.01, p < .001; CFI = 0.96; TLI = 0.96 and RMSEA = 0.045 (CI 0.037-0.053). CONCLUSION: The Misophonia Response Scale, which is valid and reliable, will facilitate understanding of Misophonia as it is short and easy to use for self-report in research.


Assuntos
Emoções , Análise Fatorial , Humanos , Psicometria , Reprodutibilidade dos Testes , Autorrelato , Inquéritos e Questionários
3.
J Dent ; 80 Suppl 1: S19-S25, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30389429

RESUMO

OBJECTIVES: To assess the effects of enzymes and proteins in toothpastes to boost salivary defences and reduce oral bacteria growth and viability. METHODS: An in vitro study to measure levels of hypothiocyanite in saliva after treatment with a toothpaste containing enzymes and proteins (colorimetric assay). A randomised, crossover in vivo study measuring, with biochemical assays, the effect of a toothpaste containing enzymes and proteins on the levels of hydrogen peroxide and lysozyme in saliva. In vitro studies to measure, using fluorescent dyes, the effects of enzymes and proteins on bacterial membrane integrity. In vitro microbiology studies measuring the effects of enzymes and proteins on planktonic bacterial growth, in vitro studies in single and multispecies biofilms measuring the effect of toothpaste with enzymes and proteins compared to control toothpaste. RESULTS: Levels of hypothiocyanite, hydrogen peroxide and lysozyme are boosted after application of a toothpaste containing enzymes and proteins. The enzymes and proteins adversely affect the bacterial membrane integrity in Streptococcus mutans and growth of planktonic S. mutans and Fusobacterium nucleatum. In a single species biofilm model the viability of S. mutans was significantly reduced and in a 7 species biofilm model bacterial viability was reduced for a biofilm grown on a pellicle pre-treated with toothpaste containing enzymes and proteins. CONCLUSIONS: The use of a toothpaste containing enzymes and proteins can boost the natural salivary defences by increasing the levels of lysozyme and hydrogen peroxide in vivo and hypothiocyanite in vitro and reduce the growth and viability of oral bacteria in microbiological models. CLINICAL SIGNIFICANCE: The subtle effects reported here of enzymes and proteins in toothpastes on oral bacteria are consistent with both the gum health benefits reported for such toothpastes containing enzymes and proteins by Daly [1] and Pedersen [2] and the rebalancing of the oral microbiome reported by Adams [3].


Assuntos
Microbiota , Boca/microbiologia , Cremes Dentais , Biofilmes , Película Dentária , Proteínas , Saliva , Streptococcus mutans
4.
J Dairy Sci ; 100(4): 2909-2916, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28131572

RESUMO

In the United Kingdom, blanket antibiotic dry cow therapy (BDCT) is commonly prescribed. An alternate strategy is selective dry cow therapy (SDCT) whereby a teat sealant is given instead of an antibiotic to cows with a low probability of infection. Switching from BDCT to SDCT can significantly reduce antibiotic use. The aims of this study were to explore how veterinarians (vets) rationalized their prescribing decisions for mammary treatments at drying off, and the barriers and motivators they perceived to implementing SDCT. Face-to-face interviews were conducted with 20 purposively recruited vets from 6 practices in England, United Kingdom. The data were analyzed qualitatively using an inductive thematic analysis. The majority of participants stated a personal preference for SDCT because it constitutes more responsible antibiotic use. On the majority of farms, the prescribing decision was taken by a senior veterinarian and BDCT was prescribed. Less experienced vets expressed a desire to be more involved in the decision-making process. The first theme, prioritizing responsible antimicrobial prescribing, encapsulated the difficulties vets expressed engaging with farmers, conflicts of interest, and vets' determination to take action. The second theme, the effect of a vet's experience on their ability to influence farmers, focused on the specific challenges faced by less experienced vets and the importance of vets being both trusted by farmers and being knowledgeable. The third theme, vets' perceptions about the risk and complexity of implementing SDCT, revealed markedly different levels of concern and fears about adverse outcomes with teat sealants versus antibiotics. The results also showed differences in perceptions about how difficult SDCT is to implement in practice. The last theme, vets' suggestions for facilitating the introduction of SDCT, was wide ranging and provided useful insight from a veterinary perspective into ways to facilitate SDCT. Initiatives that seek to alter vets' perceptions of the risks associated with switching to using SDCT are likely to prove useful in facilitating change. Our results also suggest that it is vital for senior vets to take a leading role in facilitating farms to implement SDCT. Less experienced colleagues may benefit from more help from senior vets to gain the trust of farmers and to become involved more quickly in herd-level preventive medicine. Vets must work together and take a united approach to reduce antimicrobial use.


Assuntos
Indústria de Laticínios , Médicos Veterinários/psicologia , Animais , Antibacterianos/uso terapêutico , Anti-Infecciosos , Bovinos , Doenças dos Bovinos/prevenção & controle , Feminino
5.
Geobiology ; 14(2): 163-75, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26541089

RESUMO

The microbial communities present in two underground coal mines in the Bowen Basin, Queensland, Australia, were investigated to deduce the effect of pumping and mining on subsurface methanogens and methanotrophs. The micro-organisms in pumped water from the actively mined areas, as well as, pre- and post-mining formation waters were analyzed using 16S rRNA gene amplicon sequencing. The methane stable isotope composition of Bowen Basin coal seam indicates that methanogenesis has occurred in the geological past. More recently at the mine site, changing groundwater flow dynamics and the introduction of oxygen in the subsurface has increased microbial biomass and diversity. Consistent with microbial communities found in other coal seam environments, pumped coal mine waters from the subsurface were dominated by bacteria belonging to the genera Pseudomonas and the family Rhodocyclaceae. These environments and bacterial communities supported a methanogen population, including Methanobacteriaceae, Methanococcaceae and Methanosaeta. However, one of the most ubiquitous micro-organisms in anoxic coal mine waters belonged to the family 'Candidatus Methanoperedenaceae'. As the Archaeal family 'Candidatus Methanoperedenaceae' has not been extensively defined, the one studied species in the family is capable of anaerobic methane oxidation coupled to nitrate reduction. This introduces the possibility that a methane cycle between archaeal methanogenesis and methanotrophy may exist in the anoxic waters of the coal seam after hydrogeological disturbance.


Assuntos
Archaea/classificação , Archaea/metabolismo , Bactérias/classificação , Bactérias/metabolismo , Biota , Metano/metabolismo , Microbiologia do Solo , Archaea/genética , Archaea/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , Análise por Conglomerados , Carvão Mineral , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Mineração , Filogenia , Queensland , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
6.
Dentomaxillofac Radiol ; 42(10): 20130236, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24052254

RESUMO

OBJECTIVES: CT offers a three-dimensional solution to the inaccuracies associated with lateral cephalogram-based cephalometric analysis. However, it is associated with significant concerns regarding ionizing radiation exposure. MRI offers a non-ionizing alternative, but this has been less well investigated. We present a novel gradient echo MRI sequence ("Black Bone") and highlight the potential of this sequence in cephalometric analysis. METHODS: After regional ethics approval, "Black Bone" imaging was obtained in eight patients in whom lateral cephalograms were available. "Black Bone", T1 and T2 weighted spin echo imaging were obtained in the mid-sagittal plane, and measurements were compared with those obtained on the lateral cephalogram using both the Advantage Windows Workstation (GE Medical Systems, Buckinghamshire, UK) and the Dolphin(®) cephalometric software (v. 11.5.04.23, Premium; Dolphin Imaging, Chatsworth, CA) by one assessor. Further assessment was made by scoring the ease of landmark identification on a ten-point scale. RESULTS: "Black Bone" imaging surpassed T1 and T2 weighted imaging in terms of cephalometric landmark identification. A number of mid-sagittal cephalometric landmarks could not be clearly identified on T2 weighted imaging, making analysis impossible. Measurements on "Black Bone" demonstrated the smallest discrepancy when compared with those obtained on the lateral cephalogram. The discrepancy seen between measurements completed on mid-sagittal MRI and the lateral cephalogram was compounded by inherent inaccuracies of the lateral cephalogram. The overall mean discrepancy between distance measurements on "Black Bone" imaging and those on the lateral cephalogram was 1-2 mm. CONCLUSIONS: Overall, "Black Bone" MRI offered an improved method of cephalometric landmark identification over routine MRI sequences, and provides a potential non-ionizing alternative to CT for three-dimensional cephalometrics.


Assuntos
Cefalometria/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Pontos de Referência Anatômicos/anatomia & histologia , Queixo/anatomia & histologia , Ossos Faciais/anatomia & histologia , Estudos de Viabilidade , Humanos , Incisivo/anatomia & histologia , Mandíbula/anatomia & histologia , Maxila/anatomia & histologia , Osso Nasal/anatomia & histologia , Sela Túrcica/anatomia & histologia , Adulto Jovem
7.
Int J Oral Maxillofac Surg ; 42(11): 1397-402, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23849786

RESUMO

The TNM classification for oral malignancies has been criticized for its upstaging to T4a when tumour involves styloglossus, hyoglossus, palatoglossus and genioglossus. The aims of this study were to (1) create an anatomical computer atlas of extrinsic tongue musculature, and (2) reassess the original staging of pre-treatment archived magnetic resonance images (MRI) of tongue carcinomas using the strict extrinsic muscle criteria. The anatomy of the extrinsic tongue muscles was mapped using images from the Visible Human Project (VHP) to create a computer model of the extrinsic tongue muscles. This was co-registered with 87 archived pre-staging MRI scans of tongue carcinomas to assess tumour ingress of the extrinsic tongue muscles. Of the 87 image sets reviewed, 16 were of superficial tumours not visible on MRI. In the remaining 71 cases that showed positive extrinsic muscle tumour ingress, 52% were upstaged from T1/2/3 tumours to cT4a based upon this finding. Extrinsic lateral and genioglossus muscle invasion did not predict occult cervical lymph node invasion or disease-related survival. In conclusion, tumour invasion of styloglossus or hyoglossus would result in the majority of lateral tongue tumours being staged T4a. Such stratification is of little clinical relevance, and an alternative more reliable method is required.


Assuntos
Carcinoma de Células Escamosas/patologia , Imageamento Tridimensional/métodos , Músculos do Pescoço/anatomia & histologia , Estadiamento de Neoplasias/métodos , Músculos Palatinos/anatomia & histologia , Neoplasias da Língua/patologia , Carcinoma de Células Escamosas/classificação , Feminino , Humanos , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Estadiamento de Neoplasias/normas , Estudos Retrospectivos , Neoplasias da Língua/classificação , Projetos Ser Humano Visível
9.
Br J Radiol ; 85(1019): 1457-64, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23091288

RESUMO

OBJECTIVE: The potential risks associated with ionising radiation are well documented. We have previously reported the "black bone" MRI sequence, useful when imaging cortical bone. The objective of this paper is to report our initial experience of this technique in patients undergoing imaging of the head and neck region. METHODS: Using the departmental database those patients having had "black bone" sequences of the head and neck performed as part of their MRI examination in the preceding 5 years were identified. The radiological reports were reviewed to identify those cases where "black bone" or conventional MRI sequences had been performed in place of the requested CT, and the patient medical records for these cases were reviewed. Medical record review was also conducted for those cases where it was considered that the pathological condition requiring imaging would ordinarily be investigated with CT. RESULTS: The "black bone" sequence had been performed in 69 patients as part of routine MRI of the head and neck. Of these, 67% (n=46) were performed in combination with CT imaging, the majority of cases being primary tumours. In four cases, an MRI was performed in place of the requested CT scan. We present eight clinical cases illustrating the potential benefits of the "black bone" sequence. CONCLUSIONS: "Black bone" MRI offers a radiation-free method of imaging the head and neck, and has been successfully utilised in a range of benign and malignant conditions affecting this region. Advances in knowledge Adoption of this approach, where feasible, would be a significant advance in radiation protection.


Assuntos
Cabeça/patologia , Imageamento por Ressonância Magnética , Pescoço/patologia , Adulto , Traumatismos Craniocerebrais/diagnóstico , Traumatismos Craniocerebrais/diagnóstico por imagem , Traumatismos Craniocerebrais/patologia , Feminino , Cabeça/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Doenças Mandibulares/diagnóstico , Doenças Mandibulares/diagnóstico por imagem , Doenças Mandibulares/patologia , Pessoa de Meia-Idade , Pescoço/diagnóstico por imagem , Cistos Odontogênicos/diagnóstico , Cistos Odontogênicos/diagnóstico por imagem , Cistos Odontogênicos/patologia , Tomografia Computadorizada por Raios X , Adulto Jovem
11.
Br J Radiol ; 85(1011): 272-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22391497

RESUMO

The potential harmful effects of ionising radiation continue to be highlighted. Radiation reduction techniques have largely consisted of low-dose techniques rather than a shift to non-ionising methods of imaging. CT scanning is frequently employed for imaging the craniofacial skeleton despite being one of the key anatomical regions for radiation protection in view of the radiosensitive lens and thyroid gland. We describe a low flip angle gradient echo MRI sequence which provides high image contrast between bone and other tissues but reduces the contrast between individual soft tissues. This permits the "black bone" to be easily distinguished from the uniformity of the soft tissues. While maintaining a repetition time of 8.6 ms and an echo time of 4.2 ms, the flip angle which provided optimised suppression of both fat and water was identified to be 5°. The biometric accuracy of this sequence was confirmed using a phantom to obtain direct anatomical measurements and comparable CT scanning. The average discrepancy between black bone MRI measurements and direct anatomical measurements was 0.32 mm. Black bone MRI therefore has the potential to reduce radiation exposure by replacing CT scanning when imaging the facial skeleton, with particular scope for imaging benign conditions in the young.


Assuntos
Imageamento por Ressonância Magnética/métodos , Crânio/anatomia & histologia , Artefatos , Biometria , Osso e Ossos/anatomia & histologia , Tecido Conjuntivo/anatomia & histologia , Humanos , Variações Dependentes do Observador , Imagens de Fantasmas
12.
Langmuir ; 27(11): 6674-82, 2011 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-21545121

RESUMO

In this paper, the role of the different structural isomers of the anionic surfactant sodium para-dodecyl benzene sulfonate, LAS, on surface adsorption and solution self-assembly has been studied. Using a combination of neutron reflectivity, NR, and small angle neutron scattering, SANS, the effect of mixing an isomer with a short symmetric hydrocarbon chain with one which has an asymmetric hydrocarbon chain on both the equilibrium surface adsorption behavior and the solution microstructure of the mixtures, both in the presence and absence of a divalent cation (Ca(2+)), has been investigated. In the absence of electrolyte, the LAS isomer mixtures form small charged globular micelles throughout the composition range studied. The micelle aggregation number increases with the increase in the asymmetric isomer content, reflecting an increase in the packing efficiency within the micelle. The addition of calcium ions promotes the formation of planar aggregates, as multilamellar vesicles, but only when the symmetric LAS isomer is the major component of the mixture. At a surfactant concentration just above the critical micelle concentration, CMC, and in the absence of electrolyte, the variation in the surface composition is close to the solution composition. Regular solution theory, RST, calculations show that this variation is also close to what is expected for ideal mixing. The addition of Ca(2+) ions induces a different surface behavior, resulting in the formation of multilayer structures at the interface throughout the entire composition range.


Assuntos
Benzeno/química , Cátions Bivalentes/química , Adsorção , Isomerismo , Soluções , Propriedades de Superfície
13.
Br J Radiol ; 83(995): 927-33, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20965903

RESUMO

MRI plays a crucial but under utilized role in the surgical management of lingual squamous cell carcinoma (SCC). Measurement of three-dimensional tumour volume (TV) has the potential to guide management of clinically negative cervical lymph nodes and address deficiencies in current TNM staging criteria This work studied the value of MRI-measured TV as a predictor of 2 year disease-related survival (DRS) and disease-free survival (DFS), as well as occult cervical lymph node metastasis (OM) in lingual cancer. TV was determined by manually segmenting the tumour contour in each image slice and using the resulting pixel value to calculate the three-dimensional extent of disease. TV was also compared with the more established measure of tumour thickness (TT) Significant differences in DRS (χ²(1) = 7.7, Hazard ratio (HR) = 7.3, p = 0.005) and DFS (χ²(1) = 5.6, HR = 4.3, p = 0.02) at two years were found using a cut-off of 8 cm³. Similarly, a significant relationship between TV and occult cervical lymph node metastasis was discovered using a 3 cm³ cut-off (OR = 6.7, p = 0.02, Fisher's Exact Test).


Assuntos
Carcinoma de Células Escamosas/patologia , Imageamento por Ressonância Magnética/métodos , Neoplasias Bucais/patologia , Carga Tumoral , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/secundário , Carcinoma de Células Escamosas/cirurgia , Intervalo Livre de Doença , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/mortalidade , Neoplasias Bucais/cirurgia , Pescoço , Esvaziamento Cervical/métodos , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Adulto Jovem
14.
J Radiol Prot ; 30(2): 139-47, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20530859

RESUMO

The relationship between patient cross-sectional area and both volume CT dose index (CTDI) and dose length product was explored for abdominal CT in vivo, using a 16 multidetector row CT (MDCT) scanner with automatic exposure control. During a year-long retrospective survey of patients with MDCT for symptoms of abdominal sepsis, cross-sectional areas were estimated using customised ellipses at the level of the middle of vertebra L3. The relationship between cross-sectional area and the exposure parameters was explored. Scans were performed using a LightSpeed 16 (GE Healthcare Medical Systems, Milwaukee, WI) operated with tube current modulation. From a survey of 94 patients it was found that the CTDI increased with the increase in patient cross-sectional area. The relationship was logarithmic rather than linear, with a least-squares fit to the data (R(2) = 0.80). For abdominal CT the cross-sectional area gave a measure of patient size based on the region of the body to be exposed. Exposure parameters increased with increasing cross-sectional area and the greater radiation exposure of larger patients was partly a consequence of their size. Given increasing obesity levels we believe that cross-sectional area and scan length should be added to future dose surveys, allowing patient size to be considered as a factor of relevance when examining population doses.


Assuntos
Abdome/anatomia & histologia , Carga Corporal (Radioterapia) , Tamanho Corporal , Doses de Radiação , Radiografia Abdominal/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Medição de Risco , Estatística como Assunto , Reino Unido/epidemiologia
15.
Langmuir ; 26(13): 10614-26, 2010 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-20423066

RESUMO

The surface adsorption behavior and the solution microstructure of mixtures of the C(6) isomer of anionic surfactant sodium para-dodecyl benzene sulfonate, ABS, with nonionic surfactant monodecyl triethyleneglycol ether, C(10)E(3,) have been investigated using a combination of neutron reflectivity, NR, and small-angle neutron scattering, SANS. In solution, the mixing of C(10)E(3) and ABS results in the formation of small globular micelles over most of the composition range (100:0 to 20:80 ABS/C(10)E(3)). Planar aggregates (lamellar or unilamellar vesicles, ULV) are observed for solution compositions rich in the nonionic surfactant (>80 mol % nonionic). Prior to the transition to planar aggregates, the micelle aggregation number increases with increasing nonionic composition. The lamellar-phase region is preceded by a narrow range of composition over which mixtures of micelles and small unilamellar vesicles coexist. The variation in surface absorption behavior with solution composition shows a strong surface partitioning of the more surface-active component, C(10)E(3). This pronounced departure from ideal mixing is not readily explained by existing surfactant mixing theories. In the presence of Ca(2+) ions, a more complex evolution of solution phase behavior with solution composition is observed. The lamellar-phase region occurs over a broader range of solution compositions at the expense of the small-vesicle phase. The phase boundaries are shifted to lower nonionic compositions, and the extent to which the solution-phase diagrams are modified increases with increasing calcium ion concentration. The SANS data for the large planar aggregates are consistent with large polydisperse flexible unilamellar vesicles. In the presence of Ca(2+) ions, the surface adsorption patterns become more consistent with ideal mixing in the nonionic-rich region of the surface-phase diagram. However, in the ABS-rich regions the surface behavior is more complex because of the spontaneous formation of more complex surface microstructures (bilayers to multilayers). Both in water and in the presence of Ca(2+) ions the variations in the surface adsorption behavior and in the solution mesophase structure do not appear to be closely correlated.


Assuntos
Alcanossulfonatos/química , Ânions/química , Soluções/química , Tensoativos/química , Adsorção , Cloreto de Cálcio/química , Propriedades de Superfície
16.
Br J Radiol ; 82(975): 190-7, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18955415

RESUMO

The further development of multidetector row CT (MDCT) has led to changes in the application and examination technique, leading to a need to justify the level and frequency of radiation exposure associated with MDCT. A literature review of how the use of modern scanners has affected diagnosis was undertaken, followed by a year-long retrospective study of MDCT scans of patients presenting with symptoms of abdominal sepsis. The diagnostic accuracy of detecting causes of abdominal sepsis using this technology was sought. Scans were performed using a LightSpeed 16 system (GE Healthcare Medical Systems, Slough, UK and Milwaukee, WI). Clinical diagnoses were based upon surgical and histopathological findings, treatment outcome and follow-up scans. System dose parameters recorded were the dose-length product (DLP) and volume CT dose index. The literature on investigating suspected abdominal sepsis has not been updated significantly since the time of conventional CT. 94 patients were included in the study; causes of abdominal sepsis could be detected with a sensitivity of 0.95 and a specificity of 0.91. Repeat examination and cumulative exposure was a key finding. Patients with abscesses and acute pancreatitis had the highest number of scanner visits; patients with diverticular disease had the lowest number of visits, lowest cumulative DLP and shortest stay in hospital. Cumulative DLP was affected by scan length, number of scans and patient size. In conclusion, diagnostic accuracy data for MDCT scans using 16 slices confirm that CT remains a suitable modality for imaging abdominal sepsis but scope for dose constraint exists.


Assuntos
Dor Abdominal/diagnóstico por imagem , Gastroenteropatias/diagnóstico por imagem , Sepse/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Dor Abdominal/etiologia , Protocolos Clínicos , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
17.
Langmuir ; 23(20): 10140-9, 2007 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-17725368

RESUMO

Neutron reflectivity (NR) and small angle neutron scattering (SANS) have been used to investigate the equilibrium surface adsorption behavior and the solution microstructure of mixtures of the anionic surfactant sodium 6-dodecyl benzene-4 sulfonate (SDBS) with the nonionic surfactants monododecyl octaethylene glycol (C12EO8) and monododecyl triiscosaethylene glycol (C12EO23). In the SDBS/C12EO8 and SDBS/C12EO23 solutions, small globular mixed micelles are formed. However, the addition of Ca2+ ions to SDBS/C12EO8 results in a transition to a vesicle phase or a mixed vesicle/micellar phase for SDBS rich compositions. In contrast, this transition hardly exists for the SDBS/C12EO23 mixture, and occurs only in a narrow composition region which is rich in SDBS. The adsorption of the SDBS/C12EO8 mixture at the air-solution interface is in the form of a mixed monolayer, with a composition variation that is not consistent with ideal mixing. In water and in the presence of NaCl, the nonideality can be broadly accounted for by regular solution theory (RST). At solution compositions rich in SDBS, the addition of Ca2+ ions results in the formation of multilayer structures at the interface. The composition range over which multilayer formation exists depends upon the Ca2+ concentration added. In comparison, the addition of a simple monovalent electrolyte, NaCl, at the same ionic strength does not have the same impact upon the adsorption, and the surface structure remains as a monolayer. Correspondingly, in solution, the mixed surfactant aggregates remain as relatively small globular micelles. In the presence of Ca2+ counterions, the variation in surface composition with solution composition is not well described by RST over the entire composition range. Furthermore, the mixing behavior is not strongly correlated with variations in the solution microstructure, as observed in other related systems.

19.
J Mol Cell Cardiol ; 39(1): 159-64, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15893765

RESUMO

Nitric oxide (NO) derived from neuronal nitric oxide synthase (nNOS) facilitates cardiac vagal neurotransmission and bradycardia in vitro. Here we provide evidence of rapid (within 9 h) protein expression and increased vagal responsiveness in vivo following targeted gene transfer of nNOS into the cardiac vagus of the pig. Right vagi were injected with vector encoding nNOS (Ad.nNOS) or saline, while left vagi received an injection of vector encoding enhanced green fluorescent protein (Ad.eGFP). Enhanced nNOS protein expression was detected exclusively in the right vagus nerve, with no evidence of iNOS expression. This was associated with increased baroreflex sensitivity and greater heart rate responsiveness to right vagal stimulation. In contrast, responsiveness of left vagi, or sham-injected right vagi remained constant over the same time period. Basal heart rate was unchanged following gene transfer, suggesting no change in vagal tone. These results support the pre-/post-ganglionic synapse as a site for NO-mediated facilitation of vagal bradycardia in the pig. In addition they demonstrate in vivo that functional gene expression induced with adenoviral vectors occurs earlier than first thought, and may therefore, provide a novel intervention to acutely modulate the neural control of cardiac excitability.


Assuntos
Técnicas de Transferência de Genes , Proteínas do Tecido Nervoso/genética , Óxido Nítrico Sintase/genética , Sistema Nervoso Parassimpático/fisiologia , Nervo Vago/fisiologia , Animais , Barorreflexo/fisiologia , Bradicardia/genética , Estimulação Elétrica , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Frequência Cardíaca/genética , Masculino , Proteínas do Tecido Nervoso/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo I , Suínos
20.
Br J Radiol ; 78(927): 198-201, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15730983

RESUMO

A panel of 17 trainee maxillofacial surgeons viewed 23 cases of facial trauma, demonstrated on radiographs, axial CT images and three-dimensional (3D) reformatted CT images in a standardized viewing format under standard conditions. Their diagnostic interpretation, extraction of information relevant to surgical management and subjective evaluation of each modality were recorded by standard questionnaire and compared with a gold standard evaluation by a consultant radiologist and surgeon reading based on results of clinical management. There were clear and measurable differences in the viewers' evaluations of radiographs, CT and 3D reformatted images. Overall, surgeons showed more accurate diagnostic reading of radiographs and 3D reformatted images. This was in contrast to their subjective assessment of the clinical value of each modality, which showed a strong preference for 3D over all other techniques and for CT over radiographs. However the perceived benefit of axial CT images over radiographs was not reproduced on objective testing in this group; surgeons appear to perform less well in interpreting CT images than their subjective response to the modality would suggest. This work has supported the view that surgeons value 3D imaging as a front-line tool in the evaluation and management of selected cases of acute facial trauma. We have demonstrated that the perceived benefits of 3D reformatted CT to surgeons appear real.


Assuntos
Traumatismos Faciais/diagnóstico por imagem , Imageamento Tridimensional/métodos , Tomografia Computadorizada por Raios X/métodos , Humanos , Processamento de Imagem Assistida por Computador/métodos
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