1,844 research outputs found
CCD Washington photometry of four poorly studied open clusters in the two inner quadrants of the galactic plane
Complementing our Washington photometric studies on Galactic open clusters
(OCs), we now focus on four poorly studied OCs located in the first and fourth
Galactic quadrants, namely BH 84, NGC 5381, BH 211 and Czernik 37. We have
obtained CCD photometry in the Washington system and passbands down
to 18.5 magnitudes for these four clusters. Their positions and
sizes were determined using the stellar density radial profiles. We derived
reddening, distance, age and metallicity of the clusters from extracted
color-magnitude diagrams (CMDs), using theoretical isochrones
computed for the Washington system. There are no previous photometric data in
the optical band for BH 84, NGC 5381 and BH 211. The CMDs of the observed
clusters show relatively well defined main sequences, except for Czernik 37,
wherein significant differential reddening seems to be present. The red giant
clump is clearly seen only in BH 211. For this cluster, we estimated the age in
(1000) Myr, assuming a metallicity of = 0.019. BH 84 was
found to be much older than it was previously believed, while NGC 5381 happened
to be much younger than previously reported. The heliocentric distances to
these clusters are found to range between 1.4 and 3.4 kpc. BH 84 appears to be
located at the solar galactocentric distance, while NGC 5381, BH 211 and
Czernik 37 are situated inside the solar ring.Comment: 30 pages, 9 figures, 10 table
Hydrolysis of lactose: estimation of kinetic parameters using Artificial Neural Networks
The analysis of any kinetic process involves the development of a mathematical model with predictive purposes. Generally, those models have characteristic parameters that should be estimated experimentally. A typical example is Michaelis-Menten model for enzymatic hydrolysis. Even though conventional kinetic models are very useful, they are only valid under certain experimental conditions. Besides, frequently large standard errors of estimated parameters are found due to the error of experimental determinations and/or insufficient number of assays. In this work, we developed an artificial neural network (ANN) to predict the performance of enzyme reactors at various operational conditions. The net was trained with experimental data obtained under different hydrolysis conditions of lactose solutions or cheese whey and different initial concentrations of enzymes or substrates. In all the experiments, commercial beta-galactosidase either free or immobilized in a chitosan support was used. The neural network developed in this study had an average absolute relative error of less than 5% even using few experimental data, which suggests that this tool provides an accurate prediction method for lactose hydrolysisFil: Cuellas, Anahí V.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Oddone, Sebastián. Universidad Argentina de la Empresa. Facultad de Ingeniería y Ciencias Exactas; ArgentinaFil: Mammarella, Enrique José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Rubiolo, Amelia Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentin
Retinal functional changes measured by frequency-doubling technology in patients treated with hydroxychloroquine.
BACKGROUND:
Antimalarial drugs such as chloroquine (CQ) and hydroxychloroquine (HCQ) are mainly used in the treatment of rheumatologic diseases, and their use may be associated with irreversible retinal toxicity. Previous studies indicate early paracentral visual field loss (Humphrey 10-2) in patients taking HCQ". These paracentral defects appear before changes in other clinical parameters as visual acuity and fundoscopy. The mechanism of CQ toxicity remains unclear. It was reported that toxic doses of CQ administered for as long as 4.5 years to Rhesus monkeys caused an initial dramatic effect on ganglion cells, followed later by photoreceptors and RPE degeneration. The purpose of this study is to explore early retinal functional changes measured by frequency-doubling technology (FDT) in patients treated with hydroxychloroquine (HCQ).
METHODS:
Forty-eight eyes of 48 subjects treated with hydroxychloroquine (HCQ), with no signs of retinal toxicity, and 36 eyes of 36 age and sex-matched healthy subjects were enrolled in this cross-sectional, prospective, observational, case control study. Functional testing included frequency-doubling Humphrey-matrix perimetry (FDP), white-on-white Humphrey visual field perimetry (HFA), using the 24-2 and 10-2 threshold programs, multifocal electroretinogram (mfERG, Veris 4.9) and low contrast sensitivity (CS) measurement.
RESULTS:
FDP mean deviation (MD) was found to be significantly reduced in HCQ-treated patients compared to controls both in the 24-2 (-1.38 ± 2.41 dB vs 0.21 ± 1.83 dB, p < 0.01) and in the 10-2 program (-0.97 ± 2.88 dB vs 0.15 ± 1.72 dB, p < 0.01). FDP pattern standard deviation (PSD) was found to be significantly worse in HCQ-treated patients compared to controls both in the 24-2 (2.70 ± 0.65 dB vs 2.41 ± 0.31 dB, p < 0.01 and in the 10-2 program (2.86 ± 0.48 dB vs 2.48 ± 0.39 dB, p < 0.01). HFA PSD and CS was also significantly reduced in HCQ patients, while response amplitude densities (RAD) were similar between patients and controls. A statistically significant difference in the ratio of the 5°-10° RAD and the 0°-2.5° RAD (0.31 ± 0.08 vs 0.36 ± 0.07 respectively, p < 0.05) was found between groups.
CONCLUSION:
Frequency doubling perimetry could be useful to detect early retinal impairment in patients treated with hydroxychloroquine
Working with patients and members of the public: informing health economics in child health research
This paper considers patient and public involvement (PPI) in health economics research and how this might be facilitated. PPI refers to research carried out ‘with’ or ‘by’ members of the public and is now an important aspect of health research policies internationally. Patients and members of the public can be involved in all stages of the research cycle, from establishing whether the topic is important to influencing details of study design, wording of patient-facing documentation and interpretation and dissemination of findings. PPI has become commonplace in health services research. In the context of clinical trials, it has become imperative, with, for example, patients and members of the public informing the selection of outcome measures and recruitment methods, and qualitative research is frequently steered by PPI input regarding the content of interview topic guides and the interpretation of study findings. It is less common for PPI to be explicitly reported in the economic components of health services research. However, we argue that involvement is no less important in this area. The fundamental rationale for involving people in research is that it promotes democratic principles, research quality and relevance to service users. These arguments equally apply to health economics as to other health research disciplines. Our overarching aim in this paper is to show how health economic research might be informed by PPI. We report our experiences of PPI via case studies in child health, reflect on our learnings, and make suggestions for future research practice
Estructura de las Burbujas en la región Sureste de la Nube Mayor de Magallanes
Resumen: En este trabajo se presentan resultados preliminares obtenidos a partir del análisis efectuado a la estructura de burbujas de medianas dimensiones situadas en la región Sureste de la Nube Mayor de
Magallanes. Mediante el balance de energía determinamos los parámetros
característicos de estas estructuras (brillo superficial, densidad electrónica, medida de emisión, masa, Luminosidad, densidad ambiente, edad), lo
que nos permitirá discernir cúal es el origen (viento estelar, explosión de
supernova o algún otro mecanismo) de las diferentes burbujas que componen el supercascarón LMC 9, para de esta manera tratar de dilucidar si
los objetos analizados poseen cinemáticamente alguna identidad de conjunto, o si se trata de objetos relativamente aislados sobre el fondo general
difuso al que pertenecen.Abstract: In this work we present preliminary results obtained from
the analysis carried on the structure of middle dimensions bubbles located
in the southeast region of the Large Magellanic Cloud. We determine by
means of the energy balance the characteristics parameters of this structures (superficial brightness, electronic density, emission measure, mass,
luminosity, ambiente density, age) which will allow us to discriminate
which is the origin (stellar wind, supernova explosion, or other mechanism) of the differents bubbles that form the supershell LMC 9. So, in
this way try to elucidate if the analyzed objects have kinematically some
identity as group, or if they are objects relatively aisolated against the
diffuse background to which they belongFil: Oddone, Mónica. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Otras Ciencias Naturales y Exacta
Citicoline in ophthalmological neurodegenerative disease: A comprehensive review
Cytidine 5'-diphosphocholine has been widely studied in systemic neurodegenerative diseases, like Alzheimer's disease, Parkinson's disease, and brain ischemia. The rationale for the use of citicoline in ophthalmological neurodegenerative diseases, including glaucoma, anterior ischemic optic neuropathy, and diabetic retinopathy, is founded on its multifactorial mechanism of action and the involvement in several metabolic pathways, including phospholipid homeostasis, mitochondrial dynamics, as well as cholinergic and dopaminergic transmission, all being involved in the complexity of the visual transmission. This narrative review is aimed at reporting both pre-clinical data regarding the involvement of citicoline in such metabolic pathways (including new insights about its role in the intracellular proteostasis through an interaction with the proteasome) and its effects on clinical psychophysical, electrophysiological, and morphological outcomes following its use in ophthalmological neurodegenerative diseases (including the results of the most recent prospective randomized clinical trials)
Comparison of Travoprost and Bimatoprost plus timolol fixed combinations in open-angle glaucoma patients previously treated with latanoprost plus timolol fixed combination
To compare the ocular hypotensive effect of bimatoprost plus timolol and travoprost plus timolol fixed combinations in glaucoma patients whose disease was controlled but had not reached their target intraocular pressure (IOP) with the fixed combination of latanoprost plus timolol
Recruitment of ethnic minority patients to a cardiac rehabilitation trial: The Birmingham Rehabilitation Uptake Maximisation (BRUM) study [ISRCTN72884263]
Background: Concerns have been raised about low participation rates of people from minority ethnic groups
in clinical trials. However, the evidence is unclear as many studies do not report the ethnicity of participants and
there is insufficient information about the reasons for ineligibility by ethnic group. Where there are data, there
remains the key question as to whether ethnic minorities more likely to be ineligible (e.g. due to language) or
decline to participate. We have addressed these questions in relation to the Birmingham Rehabilitation Uptake
Maximisation (BRUM) study, a randomized controlled trial (RCT) comparing a home-based with a hospital-based
cardiac rehabilitation programme in a multi-ethnic population in the UK.
Methods: Analysis of the ethnicity, age and sex of presenting and recruited subjects for a trial of cardiac
rehabilitation in the West-Midlands, UK.
Participants: 1997 patients presenting post-myocardial infarction, percutaneous transluminal coronary angioplasty
or coronary artery bypass graft surgery.
Data collected: exclusion rates, reasons for exclusion and reasons for declining to participate in the trial by ethnic
group.
Results: Significantly more patients of South Asian ethnicity were excluded (52% of 'South Asian' v 36% 'White
European' and 36% 'Other', p < 0.001). This difference in eligibility was primarily due to exclusion on the basis of
language (i.e. the inability to speak English or Punjabi). Of those eligible, similar proportions were recruited from
the different ethnic groups (white, South Asian and other). There was a marked difference in eligibility between
people of Indian, Pakistani or Bangladeshi origin
The Reliability of Anamnestic Data in the Management of Clostridium Tetani Infection in Elderly
Background: Tetanus infection remains a significant complication of wounds. Because most tetanus treatment guidelines rely on anamnestic data collected directly from patients, the congruence between anamnesis and laboratory evidence must be verified, especially in the elderly population. Aim: Assess, in both the geriatric population (>65) and the non-geriatric one, the reliability of anamnestic data for managing patients with tetanus-risk wounds, identified categories of populations most exposed to non-vaccination coverage, and assessed the agreement of the Tetanos Quick Stick (TQS) results with the therapy performed (administration of tetanus vaccine or immunoglobulin). Methods: In this retrospective single-center observational study, patients were asked their immunization status against tetanus vaccination. The decision to administer a vaccine or immunoglobulin was therefore clinical and based on anamnestic criteria. The TQS test was then given to patients who were unaware of their immunity status. Patients who thought they knew it but were not sure were given the TQS test to determine whether the anamnestic collection was supported by the test. The TQS test results were compared with the anamnestic data. Results: Most patients, geriatric and not geriatric, did not know their immune status. Among those who reported knowing their immune status, there was no agreement between the vaccine coverage declared by patients and the TQS test results (p < 0.001), mainly in geriatric patients but also in the control group. Elderly and women had significantly lower positive TQS test results (p < 0.001). There was a statistically significant discrepancy (p < 0.001) between the therapy based on anamnestic data and the TQS test results. Conclusion: The reliability of anamnestic data for the management of patients with tetanus-risk wounds is low and decreases with age, becoming minimal in geriatric patients. Elderly and women are less likely to have an effective vaccination status against tetanus
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