9,838 research outputs found
Tilt Training Increases Vasoconstrictor Reserve in Patients with Neurocardiogenic Syncope
A síncope neurocardiogénica (SNc) é uma entidade clínica comum, resultante de uma
resposta autonómica reflexa excessiva durante o stress ortostático. As diferentes opções terapêuticas são controversas e de eficácia limitada. O treino de ortostatismo (TTr) tem-se mostrado uma alternativa prometedora no tratamento destes doentes (D). No entanto, permanece por esclarecer o seu mecanismo de acção e o impacto clínico numa população com SNc recorrente.
Objectivo: Caracterizar a resposta hemodinâmica e autonómica durante um programa de TTr em doentes com SNc refratária às medidas convencionais.
População e métodos: Foram estudados 28D (50% do sexo masculino, 41±14 anos), sem evidência de cardiopatia, com SNc documentada em teste de ortostatismo passivo. O TTr incluiu 9 sessões hospitalares (3x/semana, 30 minutos) com monitorizac¸ão contínua de pressão arterial
e frequência cardíaca (60◦ - 6 sessões - 70◦ - 3 sessões), complementadas com treino diário no domicílio e elevação da cabeceira a 10◦ durante o sono. O volume sistólico, o débito cardíaco, a resistência vascular periférica, a sensibilidade do barorreflexo e a variabilidade da frequência cardíaca foram calculados. Todos os doentes foram reavaliados no fim do 1.◦ mês e no final de
cada 6 meses num período máximo de 36 meses (follow-up 24±12 meses).
Resultados: Ao longo das sessões de TTr verificou-se um aumento significativo e consistente da resistência total periférica (1485±225 vs. 1591±187 dyne*s/cm−5, p < 0,05) associado a uma diminuição do seu desvio-padrão (206±60 vs. 150±42, p < 0,05). Durante o período de follow-up, houve recorrência de síncope em 5D (19%), com redução significativa do número de
síncopes (4,0±3,2/D nos 12 meses pre-TTr vs. 1,4±0,8/D pos-TTr, p < 0,05). Conclusão: Em doentes com SNc refratária, o TTr mostrou ser uma opção terapêutica eficaz, com benefício a longo prazo. A melhor tolerância ao ortostatismo parece resultar do aumento
da reserva vasoconstritora e da sua menor variabilidade
O Treino de Ortostatismo (Tilt Training) Aumenta a Reserva Vasoconstritora em Doentes com Síncope Reflexa Neurocardiogénica
Neurocardiogenic syncope (NCS) is a common clinical entity resulting from an excessive reflex autonomic response, particularly during orthostatism. Treatment options are controversial and of limited effectiveness. Tilt training (TT) is a promising option to treat these patients. However, its mechanism of action and clinical impact remain unclear.
OBJECTIVE: To characterize hemodynamic and autonomic responses during a TT program in patients with NCS refractory to conventional measures.
METHODS: We studied 28 patients (50% male, mean age 41±14 years) without structural heart disease, with NCS documented by tilt testing. The TT program included 9 tilt sessions (3 times a week, 30 min) (60° - 6 sessions, 70° - 3 sessions), under ECG and blood pressure monitoring combined with home orthostatic self-training and 10° head-up during sleep. Systolic volume, cardiac output, total peripheral resistance, baroreflex sensitivity and heart-rate variability were computed. Patients were reassessed at 1 month and every 6 months for a maximum of 36 months (24±12 months).
RESULTS: Over the course of the TT program there was a significant increase in total peripheral resistance (1485±225 vs. 1591±187 dyn·s·cm(-5), p<0.05), with a decrease in standard deviation (206±60 vs. 150±42, p<0.05). During follow-up, syncope recurred in five patients (19%), with a significant reduction in the number of episodes (4.0±3.2/patient in the 12 months before TT vs. 1.4±0.8/patient post-TT, p<0.05).
CONCLUSION: In refractory NCS, TT may be an effective therapeutic option, with long-term benefits. These results appear to be due to an increase in vasoconstrictor reserve combined with a reduction in its variance
Towards e-cities. An Atlas to enhance the public realm through interactive urban cyber-physical devices
Cyber-physical devices are the backbone of a postdigital society in which the virtual and real spaces are seamlessly integrated by ubiquitous computing and networking. The incorporation of such devices in public space is a central subject of a strategic Research Project that gathers a multidisciplinary team from architecture, product design, polymer science and ICT R&D units. This paper frames the key roles of public space and ICTs for UN Sustainable Development Goals and sustainable smart cities. It also reports the architecture R&D unit review on the relations between public space, community, environment and digital interfaces. This review was materialized in an Atlas that collects, classifies and relates a corpus of heterogeneous urban cyber-physical projects case studies. We expand on three main framing concepts (Digital Twin, Interface, Awareness) and identify trends on the devices’ design and deployment strategies to counteract digitally hostile environments and early obsolescence. We also suggest the rising of new types of urban devices aiming at expanding the liveliness of urban places, the knowledge of urban life and the users’ environmental consciousness. The lessons learned from the Atlas fed the design guidelines for a developing demonstrator of a new breed of environmentally sensible interactive urban devices
Development of cellulose acetate membranes containing nanoparticles for water applications
The growth of human population and inherent activities, the improper industrialization practices, the direct
addition of materials TO the waterway, and the excessive use of fertilizers containing phosphates to increase
the production of crops are the main sources for the high input of phosphates in water bodies. These effects
have been causing eutrophication, and bacterial contamination of the water. In fact, the bacteria present in the
water can cause harmful disease, sickness or other problems to the human being. Moreover, the excess of
phosphates in the aquatic system induces excessive growth of plants, which consume oxygen of the water
body, thereby creating the state of hypoxia, which causes a reduction in specific fish and other animals.
Therefore, the removal of phosphates from eutrophic waters and bacteria are crucial to avoid health problems,
especially near urban areas[1].
The most common way to purify water is through membrane separation processes, in fact, cellulose acetate
(CA) membranes have been used for reverse osmosis membranes [2] for converting impaired water into
fresh-water. However, several components can be incorporated into cellulose structure to allow the
development of membranes for different applications[3].
The present work aims to develop a hybrid membrane based on CA with embedded silver and/or aluminium
nanoparticles, for the remediation of contaminated aquatic environments with microorganism, which can also
be used for removal of water contaminated with phosphate ion. Therefore, CA membranes were obtained by
solution casting, where silver and/or aluminium nanoparticles were chemical reduced in-situ. Silver
nanoparticles (Ag-NPs) were synthesized using silver nitrate and sodium borohydride as reducing agent.
Otherwise, aluminium nanoparticles (Al-NPs) were obtained using aluminium isopropoxide as the starting
precursor in the presence of acid.
The detection of Al-NPs in the membranes was carried out by FTIR spectra analysis, which showed that Al-O
bonds were formed between the aluminium precursor and the CA. The study of phosphorus adsorption kinetics
in membranes with embedded Al-NPs were proven to be efficient for the removal of phosphorus. This
membrane showed considerable ability to remove phosphate ions from aqueous solutions at low aluminium
nanoparticle content into the CA/Ag-NPs matrices. In-situ the developed membranes showed good
antimicrobial behaviour preventing the growth of microorganisms. The results indicate that the synthesized
CA/Ag-NPs/Al-NPs membranes could have potential to be used in the remediation of water resources
Relationship of Left Ventricular Global Longitudinal Strain with Cardiac Autonomic Denervation As Assessed by 123I-mIBG Scintigraphy in Patients with Heart Failure with Reduced Ejection Fraction Submitted to Cardiac Resynchronization Therapy: Assessment of Cardiac Autonomic Denervation by GLS in Patients with Heart Failure with Reduced Ejection Fraction Submitted to CRT
BACKGROUND:
Heart failure (HF) is associated with cardiac autonomic denervation (AD), which can be non-invasively assessed by 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy and has prognostic implications. We aimed to study the relationship between myocardial contractility assessed by global longitudinal strain (GLS) and AD assessed by 123I-mIBG scintigraphy in advanced HF.
METHODS/RESULTS:
BETTER-HF is a prospective randomized clinical trial including HF patients (pts) submitted to cardiac resynchronization therapy (CRT) who are submitted to a clinical, echocardiographic, and scintigraphic assessment before and 6 months after CRT. 81 pts were included. An echocardiographic response (absolute increase in left ventricular ejection fraction ≥ 10%) was observed in 73.7% of pts. A higher baseline late heart-to-mediastinum ratio (HMR) was associated with a better echocardiographic response. There was a significant association between late HMR and GLS at baseline and 6 months. At baseline, GLS had an AUC of 0.715 for discrimination for a late HMR < 1.6. A GLS cut-off of - 9% maximized the likelihood of correctly classifying a pt as having severe AD (HMR < 1.6).
CONCLUSION:
Myocardial contractility as assessed by GLS is moderately correlated with AD as assessed by 123I-mIBG scintigraphy and has a good discrimination for the identification of severe cardiac denervation. GLS may allow for a more readily accessible estimation of the degree of AD in advanced HF pts.info:eu-repo/semantics/publishedVersio
K-Nearest Oracles Borderline Dynamic Classifier Ensemble Selection
Dynamic Ensemble Selection (DES) techniques aim to select locally competent
classifiers for the classification of each new test sample. Most DES techniques
estimate the competence of classifiers using a given criterion over the region
of competence of the test sample (its the nearest neighbors in the validation
set). The K-Nearest Oracles Eliminate (KNORA-E) DES selects all classifiers
that correctly classify all samples in the region of competence of the test
sample, if such classifier exists, otherwise, it removes from the region of
competence the sample that is furthest from the test sample, and the process
repeats. When the region of competence has samples of different classes,
KNORA-E can reduce the region of competence in such a way that only samples of
a single class remain in the region of competence, leading to the selection of
locally incompetent classifiers that classify all samples in the region of
competence as being from the same class. In this paper, we propose two DES
techniques: K-Nearest Oracles Borderline (KNORA-B) and K-Nearest Oracles
Borderline Imbalanced (KNORA-BI). KNORA-B is a DES technique based on KNORA-E
that reduces the region of competence but maintains at least one sample from
each class that is in the original region of competence. KNORA-BI is a
variation of KNORA-B for imbalance datasets that reduces the region of
competence but maintains at least one minority class sample if there is any in
the original region of competence. Experiments are conducted comparing the
proposed techniques with 19 DES techniques from the literature using 40
datasets. The results show that the proposed techniques achieved interesting
results, with KNORA-BI outperforming state-of-art techniques.Comment: Paper accepted for publication on IJCNN 201
An Ensemble Generation Method Based on Instance Hardness
In Machine Learning, ensemble methods have been receiving a great deal of
attention. Techniques such as Bagging and Boosting have been successfully
applied to a variety of problems. Nevertheless, such techniques are still
susceptible to the effects of noise and outliers in the training data. We
propose a new method for the generation of pools of classifiers based on
Bagging, in which the probability of an instance being selected during the
resampling process is inversely proportional to its instance hardness, which
can be understood as the likelihood of an instance being misclassified,
regardless of the choice of classifier. The goal of the proposed method is to
remove noisy data without sacrificing the hard instances which are likely to be
found on class boundaries. We evaluate the performance of the method in
nineteen public data sets, and compare it to the performance of the Bagging and
Random Subspace algorithms. Our experiments show that in high noise scenarios
the accuracy of our method is significantly better than that of Bagging.Comment: Paper accepted for publication on IJCNN 201
Plane-mirroring anomaly in the cosmic microwave background maps
The plane-mirror symmetry previously noticed in the Cosmic Microwave
Background (CMB) temperature anisotropy maps of Wilkinson Microwave Anisotropy
Probe is shown to possess certain anomalous properties. The degree of the
randomness determined by the Kolmogorov stochasticity parameter in the both
symmetry regions appears to have identical values which, however, essentially
differ from the corresponding values for other sky regions. If the mirroring
were of cosmological origin, this would imply either additional randomizing
properties in those directions of the Universe or their different line-of-sight
depth. This analysis also provides a way to test the hypothesis of a link
between the nature of dark energy and inhomogeneities.Comment: A & A (Lett.) in press; 3 pages, 2 fig
Avaliação da atividade de extratos de Talinum triangulare e Sphagneticola trilobata sobre Trypanosoma cruzi.
O Trypanosoma cruzi, agente etiológico da doença de Chagas, atinge cerca de 18 milhões de pessoas na América Latina. Os fármacos utilizados para o tratamento geralmente são ineficazes e apresentam severos efeitos colaterais, tornando a busca por novos tratamentos bastante pertinente. Vários trabalhos têm mostrado os efeitos de extratos de plantas contra T. cruzi. As espécies vegetais Talinum triangulare (Portulacaceae) e Sphagneticola trilobata (Asteraceae) conhecidas popularmente no Brasil como caruru do Pará e vedélia, respectivamente, classificadas como invasoras, são mais resistentes ao ataque de pragas, despertando assim o interesse farmacológico. Assim, este trabalho avaliou os efeitos de extratos de T. triangulare e S. trilobata em culturas de T. cruzi
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