2,629 research outputs found
Exploring the Interconnected Role of the Oral Microbiome and Periodontal Disease in the Development and Progression of Oral Squamous Cell Carcinoma
This comprehensive review explores the complex linkage among the oral microbiome, periodontal disease, and the onset and progression of oral squamous cell carcinoma (OSCC)
The Nature and Origin of Mass Spectral Peaks
In Chapter one, a general review of mass spectrometry was made in which the history of mass spectrometry was traced from the discoveries of Goldstein and Wien to J. J. Thomson's first mass spectrograph and Aston's first mass spectrometer. The evolution and improvement in these early instruments was followed by reference to the work of Barber and Stephens, Nier, Herzog and Mattauch for the development of double-focusing instruments. Other types of instruments such as the dynamic instruments, have also been mentioned. Methods of ionisation and systems of sample introduction were described, as were the uses of mass spectrometry in analytical chemistry, both qualitatively and quantitatively, and in other branches of science. Automatic data acquisition, reduction and processing techniques, including precise mass measurement, were mentioned. Several theories useful in the interpretation of mass spectra were considered. The types of ions formed in the mass spectrometer were indicated and particular emphasis was placed on the use of metastable ions as a source of information to the organic mass spectroscopist. In addition, the relevance of thermochemical measurements, isotopic labelling, substituent effects, ion-molecule reactions and chemical ionisation to ion structure determination was discussed. In Chapter two, a new method of precise mass measurement of ions by mass spectrometry was described, and compared with methods used in the past by other workers. These ranged from the classical peak matching technique to the first semiautomatic process developed by Biemann and finally to ether more advanced automatic processes for both electrical and photographic recording, using on or off-line systems. The new mathematical method used, spline-fit interpolation was shown to yield results which were as accurate as the results obtained by the basic automatic method of Biemann; moreover, it had several advantages in its simplicity and applicability to both electrical and photographic recording systems. In Chapter three, the shape of the peaks in a double-focusing mass spectrometer in slow scans was studied. The mathematical treatment and the results showed that the peaks can be considered triangular. The calculation of the areas of the peaks accordingly became an easier task than if they were calculated using the planimeter, even in a digitisation treatment. In Chapter four, a review of ionisation phenomena was made. The definitions of ionisation and appearance potentials were given and methods for their calculation critically reviewed. Ways in which thermochemical data and structural details may be elucidated from these data were described. The ionisation and appearance potentials for the positive ions of methanol, deuterated methanol and ethylene glycol and their fragments were calculated from experimental data acquired by electron-impact on the neutral molecule. Thermochemical data and structural details derived from these observed values were discussed, and a compelling argument leading to the conclusion that the structure of the ion CH3O+ is in fact CH2OH+ was presented
Diverse Rule Sets
While machine-learning models are flourishing and transforming many aspects
of everyday life, the inability of humans to understand complex models poses
difficulties for these models to be fully trusted and embraced. Thus,
interpretability of models has been recognized as an equally important quality
as their predictive power. In particular, rule-based systems are experiencing a
renaissance owing to their intuitive if-then representation.
However, simply being rule-based does not ensure interpretability. For
example, overlapped rules spawn ambiguity and hinder interpretation. Here we
propose a novel approach of inferring diverse rule sets, by optimizing small
overlap among decision rules with a 2-approximation guarantee under the
framework of Max-Sum diversification. We formulate the problem as maximizing a
weighted sum of discriminative quality and diversity of a rule set.
In order to overcome an exponential-size search space of association rules,
we investigate several natural options for a small candidate set of
high-quality rules, including frequent and accurate rules, and examine their
hardness. Leveraging the special structure in our formulation, we then devise
an efficient randomized algorithm, which samples rules that are highly
discriminative and have small overlap. The proposed sampling algorithm
analytically targets a distribution of rules that is tailored to our objective.
We demonstrate the superior predictive power and interpretability of our
model with a comprehensive empirical study against strong baselines
The Portuguese Registry of Hypertrophic Cardiomyopathy: Overall results
INTRODUCTION:
We report the results of the Portuguese Registry of Hypertrophic Cardiomyopathy, an initiative that reflects the current spectrum of cardiology centers throughout the territory of Portugal.
METHODS:
A direct invitation to participate was sent to cardiology departments. Baseline and outcome data were collected.
RESULTS:
A total of 29 centers participated and 1042 patients were recruited. Four centers recruited 49% of the patients, of whom 59% were male, and mean age at diagnosis was 53±16 years. Hypertrophic cardiomyopathy (HCM) was identified as familial in 33%. The major reason for diagnosis was symptoms (53%). HCM was obstructive in 35% of cases and genetic testing was performed in 51%. Invasive septal reduction therapy was offered to 8% (23% of obstructive patients). Most patients (84%) had an estimated five-year risk of sudden death of <6%. Thirteen percent received an implantable cardioverter-defibrillator. After a median follow-up of 3.3 years (interquartile range [P25-P75] 1.3-6.5 years), 31% were asymptomatic. All-cause mortality was 1.19%/year and cardiovascular mortality 0.65%/year. The incidence of heart failure-related death was 0.25%/year, of sudden cardiac death 0.22%/year and of stroke-related death 0.04%/year. Heart failure-related death plus heart transplantation occurred in 0.27%/year and sudden cardiac death plus equivalents occurred in 0.53%/year.
CONCLUSIONS:
Contemporary HCM in Portugal is characterized by relatively advanced age at diagnosis, and a high proportion of invasive treatment of obstructive forms. Long-term mortality is low; heart failure is the most common cause of death followed by sudden cardiac death. However, the burden of morbidity remains considerable, emphasizing the need for disease-specific treatments that impact the natural history of the disease.info:eu-repo/semantics/publishedVersio
Public health and epidemiology journals published in Brazil and other Portuguese speaking countries
It is well known that papers written in languages other than English have a great risk of being ignored simply because these languages are not accessible to the international scientific community. The objective of this paper is to facilitate the access to the public health and epidemiology literature available in Portuguese speaking countries. It was found that it is particularly concentrated in Brazil, with some few examples in Portugal and none in other Portuguese speaking countries. This literature is predominantly written in Portuguese, but also in other languages such as English or Spanish. The paper describes the several journals, as well as the bibliographic databases that index these journals and how to access them. Most journals provide open-access with direct links in the indexing databases. The importance of this scientific production for the development of epidemiology as a scientific discipline and as a basic discipline for public health practice is discussed. To marginalize these publications has implications for a more balanced knowledge and understanding of the health problems and their determinants at a world-wide level
The characterisation of the craniofacial morphology of infants born with Zika virus:Innovative approach for public health surveillance and broad clinical applications
Background:
This study was carried out in response to the Zika virus epidemic which constituted a public health emergency and to the 2019 WHO calling for strengthened surveillance for the early detection of related microcephaly. The main aim of the study was to phenotype the craniofacial morphology of microcephaly using novel approach and new measurements, relate the characteristics to brain abnormalities in Zika infected infants in Brazil to improve clinical surveillance.
Methods:
We captured 3D images of the face and the cranial vault of 44 Zika infected infants and matched healthy controls using 3D camera. The CT scans of the brain of the infected infants were analysed.
The Principal Component Analysis (PCA) was applied to characterise the craniofacial morphology. In addition to the head circumference (HC), we introduced a new measurement, head height (HH) to measure the cranial vault. The level of brain abnormality present in the CT scans was assessed, the severity of parenchymal volume loss and ventriculomegaly was quantified.
Findings:
The PCA identified a significant difference (p <0.001) between the cranial vaults and the face of the Zika infants and that of the controls. Spearman's rank-order correlation coefficients show that the head height (HH) has a strong correlation (0.87 in Zika infants; 0.82 in Controls) with the morphology of the cranial vaults which are higher than the correlation with the routinely used head circumference (HC). Also, the head height (HH) has a moderate negative correlation (-0.48) with the brain abnormalities of parenchymal volume loss.
Interpretation:
We discovered that head height (HH), the most sensitive and discriminatory measure of the severity of cranial deformity which should be used for clinical surveillance of Zika syndrome, evaluation of other craniofacial syndromes and assessment of various treatment modalities
Hydrodynamic considerations on optimal design of a three-phase airlift bioreactor with high solids loading
The hydrodynamic study of a three-phase airlift (TPAL) bioreactor with an enlarged gas–liquid
dual separator was carried out. Different lengths and diameters of the draft tube were tested to show how
the design of the separator zone affects the hydrodynamic performance of the TPAL reactor. Ca-alginate
beads with entrapped yeast biomass at different loadings (0, 7, 14 and 21% v/v) were used in order to mimic
the solid phase of conventional high cell density systems, such as those with cells immobilized on carriers
or flocculating cells. Important information on multiphase flow and distribution of gas and solid phases
in the internal-loop airlift reactor (ALR) with high solids loading was obtained, which can be used for
suggesting optimal hydrodynamic conditions in a TPAL bioreactor with high solids loading. It is finally
suggested that the ALR with a dual separator and a downcomer to riser cross-sectional area ratio (AD/AR)
ranging from 1.2 to 2.0 can be successfully applied to batch/continuous high cell density systems, where
the uniform distribution of solid phase, its efficient separation of particles from the liquid phase, and an
improved residence time of air bubbles inside the reactor are desirable.European Community - ‘Improving Human Research Potential’ - Marie Curie Fellowship - contract number HPMF-CT-2002-01643
Desenvolvimento de um Repositório de Imagens e Base de Dados Portuguesa de Casos COVID-19: Aprendizagem e Partilha de Conhecimento em Tempo de Pandemia
info:eu-repo/semantics/publishedVersio
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