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Microplastic analysis requires effective separation and purification methods, which greatly depend on the matrix and target particle size. Microplastics-sediment extraction usually involves intermediate steps, increasing processing time and particle loss, particularly for particles <100 µm. Here, we propose an improved separation and quantification method for fine-grained sediment that minimizes microplastic loss by reducing intermediate steps. First, the sample is treated with CH3COOH, KOH and NaClO, and only transferred for the density separation (ZnCl2). The extraction efficiency, visually evaluated on spiked samples, was higher than 90% for particles >100 µm and 83% for 63-75 µm particles. This indicates that a sequential extraction method reduces the risk of particle loss, particularly of the small size fraction. Comparatively, the extraction of ABS particles (20-100 µm) was low (30%) but the recovery, assessed via µFTIR, was higher (55%). Additionally, the proposed method can be adapted to other sediment types and environmental matrices.
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Microplásticos , Poluentes Químicos da Água , Plásticos/análise , Groenlândia , Poluentes Químicos da Água/análise , Sedimentos Geológicos , Monitoramento AmbientalRESUMO
Wetland area in agricultural landscapes has been heavily reduced to gain land for crop production, but in recent years there is increased societal recognition of the negative consequences from wetland loss on nutrient retention, biodiversity and a range of other benefits to humans. The current trend is therefore to re-establish wetlands, often with an aim to achieve the simultaneous delivery of multiple ecosystem services, i.e., multifunctionality. Here we review the literature on key objectives used to motivate wetland re-establishment in temperate agricultural landscapes (provision of flow regulation, nutrient retention, climate mitigation, biodiversity conservation and cultural ecosystem services), and their relationships to environmental properties, in order to identify potential for tradeoffs and synergies concerning the development of multifunctional wetlands. Through this process, we find that there is a need for a change in scale from a focus on single wetlands to wetlandscapes (multiple neighboring wetlands including their catchments and surrounding landscape features) if multiple societal and environmental goals are to be achieved. Finally, we discuss the key factors to be considered when planning for re-establishment of wetlands that can support achievement of a wide range of objectives at the landscape scale.
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Ecossistema , Áreas Alagadas , Humanos , Conservação dos Recursos Naturais , Biodiversidade , AgriculturaRESUMO
The Naked Mole Rat (NMR), Heterocephalus glaber, provides an interesting model for studying biomarkers of longevity due to its long lifespan of more than 30 years, almost ten times longer than that of mice and rats. α-Klotho (klotho) is an aging-suppressor gene, and overexpression of klotho is associated with extended lifespan in mice. Klotho is predominantly expressed in the kidney. The expression profile of klotho in the NMR has not previously been reported. The present investigation studied the expression of klotho in the kidney of NMR with that of Rattus Norvegicus (RN) and demonstrated that klotho was expressed in the kidney of NMR at the same level as found in RN. Besides, a significant expression of Kl mRNA was found in the liver of NMR, in contrast to RN, where no hepatic expression was detected. The Klotho expression was further confirmed at the protein level. Thus, the results of the present comparative study indicate a differential tissue expression of klotho between different species. Besides its important function in the kidney, Klotho might also be of significance in the liver of NMR. It is suggested that the hepatic extrarenal expression of klotho may function as a further longevity-related factor in supplement to the Klotho in the kidney.
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Glucuronidase/genética , Longevidade/genética , Ratos-Toupeira/genética , Envelhecimento/genética , Animais , Humanos , Rim/metabolismo , Proteínas Klotho , Fígado/metabolismo , Camundongos , Ratos-Toupeira/crescimento & desenvolvimentoRESUMO
Newborn screening programs are an integral part of public health systems aiming to save lives and improve the quality of life for infants with treatable disorders. Technological advancements have driven the expansion of newborn screening programs in the last two decades and the development of fast, accurate next-generation sequencing technology has opened the door to a range of possibilities in the field. However, technological challenges with short-read next-generation sequencing technologies remain significant in highly homologous genomic regions such as pseudogenes or paralogous genes and need to be considered when implemented in screening programs. Here, we simulate 50 genomes from populations around the world to test the extent to which high homology regions affect short-read mapping of genes related to newborn screening disorders and the impact of differential read lengths and ethnic backgrounds. We examine a 158 gene screening panel directly relevant to newborn screening and identify gene regions where read mapping is affected by homologous genomic regions at different read lengths. We also determine that the patient's ethnic background does not have a widespread impact on mapping accuracy or coverage. Additionally, we identify newborn screening genes where alternative forms of sequencing or variant calling pipelines should be considered and demonstrate that alterations to standard variant calling can retrieve some formerly uncalled variants.
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Calciphylaxis is associated with significant morbidity and mortality. Palliative care (PC) is a subspecialty that treats the pain and stress of serious illness. To assess whether the role of quality of life (QoL) indices, patient-reported outcome measures and PC have been studied in patients with calciphylaxis, we performed a systematic literature review. Several databases were searched from inception to October 2016 according to modified Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. We searched for papers on calciphylaxis that mentioned the symptoms and supportive needs of patients, QoL or outcome measures to report symptom severity, and the involvement of PC. Twelve papers met the inclusion criteria. Reported patient symptoms included pain, skin lesion resolution and pruritus, with the first being the most frequently reported. Four papers measured pain using a previously verified patient-reported outcome measure, including the Visual Analogue Scale. One paper used a verified QoL measure, the Dermatology Quality of Life Index. No tool was used consistently. Eight papers reported the use of hospice care or PC in the treatment of calciphylaxis. No outcome measure was used to prompt PC involvement. Overall, QoL indices, patient-reported outcome measures and PC are underreported in the treatment of calciphylaxis. PC may be a resource to assist in symptom management and adaptive coping strategies for patients from the onset of disease.
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Calciofilaxia/terapia , Cuidados Paliativos/estatística & dados numéricos , Qualidade de Vida , Calciofilaxia/psicologia , Utilização de Instalações e Serviços , Humanos , Cuidados Paliativos/psicologia , Medidas de Resultados Relatados pelo Paciente , Projetos de PesquisaRESUMO
OBJECTIVE: To investigate patients' experiences of a new payment system for dental care in Sweden. METHODS: Twenty interviews, with 12 women and 8 men, were analysed by thematic content analysis. The interviewees were all regularly attending patients, strategically selected from five general Public Dental Service clinics in urban Gothenburg, Sweden, who had chosen a new payment system based on capitation rather than the traditional fee-for-service system. Conducted by two clinical psychologists/researchers independent of dental profession, the interviews were guided by a semi-structured schedule, which included questions about the new payment system and about dental care and oral health. All interviews were audio-recorded and transcribed verbatim. RESULTS: Two themes emerged from the analysis: "Choice" and "Commitment". The sub-themes defined patients as having chosen the new capitation scheme on their own initiative or after being influenced by relatives or by their dentist, and that the change of payment system was occasioned by previous bad (dental) experiences or in the hope of future (dental health) gain. The commitment was perceived as affording economic security and, through the contractual relationship with the provider, regular calls to attend the clinic. CONCLUSIONS: Patients were generally in favour of the new payment system for dentistry in Sweden; however, important arguments were raised to improve the system, such as better communication concerning the contract and risk assessment.
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Atitude Frente a Saúde , Capitação , Assistência Odontológica/economia , Adulto , Comportamento de Escolha , Contratos/economia , Assistência Odontológica/normas , Feminino , Humanos , Seguro Odontológico/economia , Masculino , Pessoa de Meia-Idade , Saúde Bucal , Higiene Bucal , Participação do Paciente , Satisfação do Paciente , Odontologia em Saúde Pública/economia , Pesquisa Qualitativa , Medição de Risco , Suécia , Serviços Urbanos de Saúde/economia , Adulto JovemRESUMO
The Baltic Sea is a semi-enclosed sea with a steady salinity gradient (3-30). Organisms have adapted to such low salinities, but are suspected to be more susceptible to stress. Within the frame of the integrated environmental monitoring BONUS + project "BEAST" the applicability of immune responses of the blue mussel was investigated in Danish coastal waters. The sampling sites were characterised by a salinity range (11-19) and different mixtures of contaminants (metals, PAHs and POPs), according to chemical analysis of mussel tissues. Variation partitioning (redundancy analysis) was applied to decompose salinity and contamination effects. The results indicated that cellular immune responses (total and differential haemocyte count, phagocytic activity and apoptosis) were mainly influenced by contaminants, whereas humoral factors (haemolytic activity) were mainly impacted by salinity. Hence, cellular immune functions may be suitable as biomarkers in monitoring programmes for the Baltic Sea and other geographic regions with salinity variances of the studied range.
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Mytilus edulis/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Contagem de Células Sanguíneas , Caspase 3/metabolismo , Caspase 7/metabolismo , Dinamarca , Hemolinfa/citologia , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/toxicidade , Metais Pesados/análise , Metais Pesados/toxicidade , Mytilus edulis/imunologia , Mytilus edulis/metabolismo , Compostos Orgânicos de Estanho/análise , Compostos Orgânicos de Estanho/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Salinidade , Água do Mar , Poluentes Químicos da Água/análiseRESUMO
Order parameter symmetry is one of the basic characteristics of a superconductor. The heavy fermion compound UPt3 provides a rich system for studying the competition between superconductivity and other forms of electronic order and exhibits two distinct superconducting phases that are characterized by different symmetries. We fabricated a series of Josephson tunnel junctions on the as-grown surfaces of UPt3 single crystals spanning the a-b plane. By measuring their critical current, we mapped out the magnitude of the superconducting order parameter as a function of the momentum-space direction and temperature. In the high-temperature phase, we observed a sharp node in the superconducting gap at 45 degrees with respect to the a axis; an out-of-phase component appeared in the low-temperature phase, creating a complex order parameter.
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AIM: To compare the effects of combining liraglutide (0.6, 1.2 or 1.8 mg/day) or rosiglitazone 4 mg/day (all n >or= 228) or placebo (n = 114) with glimepiride (2-4 mg/day) on glycaemic control, body weight and safety in Type 2 diabetes. METHODS: In total, 1041 adults (mean +/- sd), age 56 +/- 10 years, weight 82 +/- 17 kg and glycated haemoglobin (HbA(1c)) 8.4 +/- 1.0% at 116 sites in 21 countries were stratified based on previous oral glucose-lowering mono : combination therapies (30 : 70%) to participate in a five-arm, 26-week, double-dummy, randomized study. RESULTS: Liraglutide (1.2 or 1.8 mg) produced greater reductions in HbA(1c) from baseline, (-1.1%, baseline 8.5%) compared with placebo (+0.2%, P < 0.0001, baseline 8.4%) or rosiglitazone (-0.4%, P < 0.0001, baseline 8.4%) when added to glimepiride. Liraglutide 0.6 mg was less effective (-0.6%, baseline 8.4%). Fasting plasma glucose decreased by week 2, with a 1.6 mmol/l decrease from baseline at week 26 with liraglutide 1.2 mg (baseline 9.8 mmol/l) or 1.8 mg (baseline 9.7 mmol/l) compared with a 0.9 mmol/l increase (placebo, P < 0.0001, baseline 9.5 mmol/l) or 1.0 mmol/l decrease (rosiglitazone, P < 0.006, baseline 9.9 mmol/l). Decreases in postprandial plasma glucose from baseline were greater with liraglutide 1.2 or 1.8 mg [-2.5 to -2.7 mmol/l (baseline 12.9 mmol/l for both)] compared with placebo (-0.4 mmol/l, P < 0.0001, baseline 12.7 mmol/l) or rosiglitazone (-1.8 mmol/l, P < 0.05, baseline 13.0 mmol/l). Changes in body weight with liraglutide 1.8 mg (-0.2 kg, baseline 83.0 kg), 1.2 mg (+0.3 kg, baseline 80.0 kg) or placebo (-0.1 kg, baseline 81.9 kg) were less than with rosiglitazone (+2.1 kg, P < 0.0001, baseline 80.6 kg). Main adverse events for all treatments were minor hypoglycaemia (< 10%), nausea (< 11%), vomiting (< 5%) and diarrhoea (< 8%). CONCLUSIONS: Liraglutide added to glimepiride was well tolerated and provided improved glycaemic control and favourable weight profile.
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Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Hipoglicemiantes/administração & dosagem , Compostos de Sulfonilureia/administração & dosagem , Idoso , Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 2/sangue , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Peptídeo 1 Semelhante ao Glucagon/administração & dosagem , Humanos , Hipoglicemia/sangue , Hipoglicemia/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Rosiglitazona , Tiazolidinedionas/administração & dosagemRESUMO
We present data on the modulation of the critical current with applied magnetic field in UPt3-Cu-Pb Josephson junctions and SQUIDs. The junctions were fabricated on polished surfaces of UPt3 single crystals. The shape of the resulting diffraction patterns provides phase-sensitive information on the superconducting order parameter. Our corner junction data show asymmetric patterns with respect to magnetic field, indicating a complex order parameter, and both our junction and SQUID measurements point to a phase shift of pi, supporting the E(2u) representation of the order parameter.
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This study reports the results of a screening survey of perfluoroalkyl compounds (PFCs) in the Danish environment. The study included point sources (municipal and industrial wastewater treatment plants and landfill sites) and the marine and freshwater environments. Effluent and influent water and sewage sludge were analysed for point sources. Sediment, blue mussels (Mytilus edulis) and liver from plaice (Pleuronectes platessa), flounder (Platichthys flesus) and eel (Anguilla anguilla) were analysed for the freshwater and marine environments. The results obtained show a diffuse PFCs contamination of the Danish environment with concentrations similar to those measured in other countries with the absence of primary contamination sources such as fluorochemical production. PFOS and PFOA were generally the most dominating PFCs measured in both point sources and the aquatic environments. PFCs were found in both inflow and outflow water and sewage sludge from municipal and industrial wastewater treatment plants (WWTPs), indicating that WWTPs can be significant sources to PFCs in the environment. This is also reflected in the locally elevated PFCs concentrations found in fish like eels from shallow freshwater and marine areas. However, the highest PFCs concentrations found in fish in this study was in plaice from the Skagerrak (156 ng/g wet weight PFOS), but it is unknown if this can be related to significant sources in the North Sea region or to differences between species. The concentrations of PFCs were below the detection limit in all analysed freshwater and marine samples of sediment and mussels. Despite the relatively low PFCs concentrations measured in marine fish, the high bioaccumulation potential of PFCs, particularly PFOS, may lead to high concentrations of PFCs in marine mammals as shown by previous investigations.
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Monitoramento Ambiental , Hidrocarbonetos Fluorados/análise , Poluentes Químicos da Água/análise , Anguilla , Animais , Dinamarca , Linguado , Água Doce/química , Sedimentos Geológicos/química , Mytilus edulis/química , Mar do Norte , Água do Mar/química , Esgotos/químicaRESUMO
Total mercury (THg), methylmercury (MeHg) and stable isotopes of nitrogen (delta(15)N) and carbon (delta(13)C) were measured in three invertebrate, five fish, three seabird and three marine mammal species of central West Greenland to investigate trophic transfer of mercury in this Arctic marine food web. The food web magnification factor (FWMF) estimated as the slope of the regression between the natural logarithm of THg or MeHg concentrations (mg kg(-1) dw) and tissue delta(15)N ( per thousand) was estimated to 0.183 (SE = 0.052) for THg and 0.339 (SE = 0.075) for MeHg. The FWMFs were not only comparable with those reported for other Arctic marine food webs but also with quite different food webs such as freshwater lakes in the sub-Arctic, East Africa and Papua New Guinea. This suggests similar mechanisms of mercury assimilation and isotopic (delta(15)N) discrimination among a broad range of aquatic taxa and underlines the possibility of broad ecosystem comparisons using the combined contaminant and stable isotope approach.
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Ecossistema , Monitoramento Ambiental/métodos , Cadeia Alimentar , Mercúrio/metabolismo , Poluentes Químicos da Água/análise , Animais , Aves/metabolismo , Isótopos de Carbono , Peixes/metabolismo , Groenlândia , Invertebrados/metabolismo , Isótopos de Nitrogênio , Água do Mar , Poluentes Químicos da Água/metabolismoRESUMO
We present direct evidence for complex p-wave order parameter symmetry and the presence of dynamical chiral order parameter domains of the form px +/- ipy in the ruthenate superconductor Sr2RuO4. The domain structure creates differences in the magnetic field modulation of the critical current of Josephson junctions fabricated on orthogonal faces of Sr2RuO4 single crystals. Transitions between the chiral states of a domain or the motion of domain walls separating them generates telegraph noise in the critical current as a function of magnetic field or time and is responsible for hysteresis observed in field sweeps of the critical current. The presence of such domains confirms the p-wave triplet spin and complex (broken time-reversal symmetry) nature of the superconducting pairing state in Sr2RuO4.
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The purpose of this study was to examine the health status and gametogenetic activity in Mya arenaria clams collected at various sites in the St. Lawrence Estuary (Quebec, Canada) and in the Odense Fjord (Denmark). Clam soft tissues were analyzed for metals/metalloids and organotin compounds to confirm their exposure to these contaminants. Their health status was assessed by a test battery of biomarkers designed to measure the early biological effects of contaminants, which include expression of defence mechanisms such as xenobiotic conjugation (glutathione S-transferase), expression of stress proteins (i.e., heme oxygenase and metallothioneins), changes in gametogenetic activity, and individual morphometric characteristics. Clam tissues were also examined for the presence of oxidative damage to lipids, formation of DNA strand breaks, and alterations in heme metabolism. The results showed that clams sampled from sites with either ferry activity or intensive boat traffic in marinas were contaminated by metals/metalloids such as Ag, Al, As, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn. The clams also contained relatively high amounts of tributyltin (TBT) in their tissues (in the ng TBT/g range for both areas), with digestive glands containing more organotins than did gonadal tissues. Moreover, clams collected from TBT-contaminated sites had higher amounts of tin-heme adducts and lower total heme in their digestive glands. Condition factor, age distribution, and sex ratio were significantly altered in clams from impacted sites in the Saguenay Fjord and accompanied by an increased male/female sex ratio. Gametogenetic activity was also negatively affected, as revealed by reductions in gonadosomatic index, maturation index, aspartate transcarbamylase activity, and vitellogenin-like proteins. The Saguenay Fjord clams displayed a complex pattern of stress responses and damage such as increased heme oxygenase activity, phase 2 conjugation enzyme activity, lipid peroxidation, and altered DNA strand breaks. The integration of biomarker response data into a biomarker index at the whole-individual level (morphometric characteristics) and for various organs (gill, digestive gland, and gonad) revealed that, relative to the control site, morphological characteristics and gonadal activity were most affected at the most contaminated site, while the effects were more pronounced in the digestive gland and gill at moderately impacted sites. We conclude that the health status of M. arenaria clams at these contaminated sites is compromised, with obvious disruption of reproductive activity.
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Monitoramento Ambiental/métodos , Gametogênese/efeitos dos fármacos , Mya/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Dinamarca , Feminino , Gametogênese/fisiologia , Gônadas/química , Gônadas/efeitos dos fármacos , Masculino , Metais/análise , Metais/metabolismo , Mya/química , Mya/metabolismo , Quebeque , Processos de Determinação Sexual , Razão de Masculinidade , Compostos de Trialquitina/análiseRESUMO
AIMS: This study compared the effects of 52 weeks' treatment with pioglitazone, a thiazolidinedione that reduces insulin resistance, and glibenclamide, on insulin sensitivity, glycaemic control, and lipids in patients with Type 2 diabetes. METHODS: Patients with Type 2 diabetes were randomized to receive either pioglitazone (initially 30 mg QD, n = 91) or micronized glibenclamide (initially 1.75 mg QD, n = 109) as monotherapy. Doses were titrated (to 45 mg for pioglitazone and 10.5 mg for glibenclamide) to achieve glycaemic targets during the next 12 weeks: fasting blood glucose of < or = 7 mmol/l and 1-h postprandial blood glucose of < or = 10 mmol/l. Patients were maintained on the titrated dose for 40 weeks. RESULTS: Pioglitazone significantly increased insulin sensitivity compared with glibenclamide, as assessed by homeostasis model assessment (17.0% vs. -13.0%; P < 0.001), quantitative insulin sensitivity check index (0.011 vs. -0.007; P < 0.001) and fasting serum insulin (-1.3 pmol/l vs. 23.8 pmol/l; P = 0.007). The glibenclamide group had significantly lower HbA1c than the pioglitazone group after 12 weeks of therapy (7.8% vs. 8.3%, P = 0.015), but significantly higher HbA1c after 52 weeks of therapy (7.8% vs. 7.2%, P = 0.001). Pioglitazone significantly (vs. glibenclamide) increased mean HDL-C (P < 0.001), decreased mean triglycerides (P = 0.019), and decreased mean atherogenic index of plasma (AIP; P = 0.001) and mean total cholesterol/HDL-C (P = 0.004), without significantly elevating mean total cholesterol or mean LDL-C compared with glibenclamide. CONCLUSIONS These data suggest that the effects of pioglitazone are more sustained than those of glibenclamide for improving insulin sensitivity in patients with Type 2 diabetes, and that 52 weeks' treatment with pioglitazone has favourable effects on glycaemic control and lipoprotein profile.
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Glicemia/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glibureto/uso terapêutico , Hipoglicemiantes/uso terapêutico , Resistência à Insulina/fisiologia , Lipídeos/sangue , Tiazolidinedionas/uso terapêutico , Diabetes Mellitus Tipo 2/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PioglitazonaRESUMO
Electrical spin injection from Fe into AlxGa1-xAs quantum well heterostructures is demonstrated in small (<500 Oe) in-plane magnetic fields. The measurement is sensitive only to the component of the spin that precesses about the internal magnetic field in the semiconductor. This field is much larger than the applied field and depends strongly on the injection current density. Details of the observed hysteresis in the spin injection signal are reproduced in a model that incorporates the magnetocrystalline anisotropy of the epitaxial Fe film, spin relaxation in the semiconductor, and the dynamic polarization of nuclei by the injected spins.
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This paper presents a new method for 2-D blind homomorphic deconvolution of medical B-scan ultrasound images. The method is based on noise-robust 2-D phase unwrapping and a noise-robust procedure to estimate the pulse in the complex cepstrum domain. Ordinary Wiener filtering is used in the subsequent deconvolution. The resulting images became much sharper with better defined tissue structures compared with the ordinary images. The deconvolved images had a resolution gain along the order of 3 to 7, and the signal-to-noise ratio (SNR) doubled for many of the images used in our experiments. The method gave stable results with respect to noise and grey levels through several image sequences.
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Ultrassonografia/estatística & dados numéricos , Adulto , Engenharia Biomédica , Feminino , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Rim/diagnóstico por imagem , Imagens de Fantasmas , Antro Pilórico/diagnóstico por imagem , Ultrassonografia Mamária/estatística & dados numéricosRESUMO
Tropomyosin is an extended coiled-coil protein that influences actin function by binding longitudinally along thin filaments. The present work compares cardiac tropomyosin and the two tropomyosins from Saccharomyces cerevisiae, TPM1 and TPM2, that are much shorter than vertebrate tropomyosins. Unlike cardiac tropomyosin, the phase of the coiled-coil-forming heptad repeat of TPM2 is discontinuous; it is interrupted by a 4-residue deletion. TPM1 has two such deletions, which flank the 38-residue partial gene duplication that causes TPM1 to span five actins instead of the four of TPM2. Each of the three tropomyosin isoforms modulates actin-myosin interactions, with isoform-specific effects on cooperativity and strength of myosin binding. These different properties can be explained by a model that combines opposite effects, steric hindrance between myosin and tropomyosin when the latter is bound to a subset of its sites on actin, and also indirect, favorable interactions between tropomyosin and myosin, mediated by mutually promoted changes in actin. Both of these effects are influenced by which tropomyosin isoform is present. Finally, the tropomyosins have isoform-specific effects on in vitro sliding speed and on the myosin concentration dependence of this movement, suggesting that non-muscle tropomyosin isoforms exist, at least in part, to modulate myosin function.