Comprehensive analysis of synthetic learning applied to neonatal brain MRI segmentation.

Brain segmentation from neonatal MRI images is a very challenging task due to large changes in the shape of cerebral structures and variations in signal intensities reflecting the gestational process. In this context, there is a clear need for segmentation techniques that are robust to variations in image contrast and to the spatial configuration of anatomical structures. In this work, we evaluate the potential of synthetic learning, a contrast-independent model trained using synthetic images generated from the ground truth labels of very few subjects. We base our experiments on the dataset released by the developmental Human Connectome Project, for which high-quality images are available for more than 700 babies aged between 26 and 45 weeks postconception. First, we confirm the impressive performance of a standard UNet trained on a few volumes, but also confirm that such models learn intensity-related features specific to the training domain. We then confirm the robustness of the synthetic learning approach to variations in image contrast. However, we observe a clear influence of the age of the baby on the predictions. We improve the performance of this model by enriching the synthetic training set with realistic motion artifacts and over-segmentation of the white matter. Based on extensive visual assessment, we argue that the better performance of the model trained on real T2w data may be due to systematic errors in the ground truth. We propose an original experiment allowing us to show that learning from real data will reproduce any systematic bias affecting the training set, while synthetic models can avoid this limitation. Overall, our experiments confirm that synthetic learning is an effective solution for segmenting neonatal brain MRI. Our adapted synthetic learning approach combines key features that will be instrumental for large multisite studies and clinical applications.

Plis de passage in the superior temporal sulcus: Morphology and local connectivity.

While there is a profusion of functional investigations involving the superior temporal sulcus (STS), our knowledge of the anatomy of this sulcus is still limited by a large individual variability. In particular, an accurate characterization of the "plis de passage" (PPs), annectant gyri inside the fold, is lacking to explain this variability. Performed on 90 subjects of the HCP database, our study revealed that PPs constitute landmarks that can be identified from the geometry of the STS walls. They were found associated with a specific U-shape white-matter connectivity between the two banks of the sulcus, the amount of connectivity being related to the depth of the PPs. These findings raise new hypotheses regarding the spatial organization of PPs, the relation between cortical anatomy and structural connectivity, as well as the possible role of PPs in the regional functional organization.

Evidence of weak ferromagnetism in doped plasticized polyaniline (PANI-DDoESSA)0.5 from electron spin resonance measurements.

X-band electron spin resonance (ESR) measurements have been performed on a conducting free-standing film of polyaniline plasticized and protonated with di-n-dodecyl ester of sulfosuccinic acid (DDoESSA). The magnetic field was applied parallel and perpendicular to the plane of the film. At around 75 K a transition is observed from Pauli susceptibility to a localized state in which the spin 1/2 polarons behave as spin 1/2 dimers. A rough estimation of the intradimer and interdimer exchange constants is obtained. Below 5 K, ESR data reveal a weak ferromagnetism with the Dzyaloshinskii-Moriya vector mainly oriented in the plane of the film. The existence of a relatively well-defined n-fold axis along the chain direction in the crystalline regions confers a symmetry compatible with such analysis.

Magnetic field dependence of the magnetic susceptibility and the specific heat of the doped plasticized polyaniline (PANI-DB3EPSA)0.5.

Specific heat, magnetization and electron spin resonance (ESR) data obtained from a self-standing film of the doped plasticized polyaniline (PANI-DB3EPSA)(0.5) are shown. No long range magnetic order has been observed at zero magnetic field, above 2 K. For a magnetic field of 3.3 kOe applied perpendicular to the plane of the film, a clear signature of an induced ordered state can be seen in the specific heat data and ESR also reveals this antiferromagnetic order. An electronic contribution is detected from ESR, magnetization and specific heat; however, for T ≤ 5 K, the specific heat data show the existence of a gap. Magnetization data also show a low temperature dominant Curie behaviour which cannot be seen from ESR, probably due to a very large linewidth, suggesting short range correlations among spin 1/2 polarons.

Educating the educators at Hue Medical College, Hue, Viet Nam.

BACKGROUND: In June 2005, four faculty members from Temple University, Philadelphia, USA, conducted a nursing educator workshop in Hue, Viet Nam. Didactic and clinical instruction addressed paediatric, maternity, psychiatric and surgical nursing content as well as instructional methods and student evaluation techniques. This educator workshop was requested as means of increasing the professionalization of nursing in Viet Nam. Student nurses in Viet Nam are taught by physician-faculty. Between the cultural and economic factors that contribute to the current status and practice of nursing in Viet Nam and the lack of nurse educator role models, the nursing profession has many obstacles to overcome in their quest for increased autonomy. ACTIONS: During the workshop, in addition to modelling interactive teaching methods as they taught the classroom and clinical content, these authors also demonstrated the level of knowledge expected of nurses in the USA. CONCLUSIONS: Despite much advance planning for this workshop, there were many challenges for the USA faculty. Some of the lessons learned which might help others included having a sense of humour, maintaining flexibility in teaching styles and content, being prepared for the cultural and religious influences on health care, and utilizing all of one's nursing skills to find creative solutions when teaching nursing in another country.

UV-Vis-NIR spectroelectrochemical and in situ conductance studies of unusual stability of n- and p-doped poly(dimethyldioctylquaterthiophene-alt-oxadiazole) under high cathodic and anodic polarizations.

Combined CV studies and UV-Vis-NIR spectroelectrochemical investigations revealed an unusual stability of the p- and n-doped PMOThOD in the wide potential window of 4 V. The n-doping process occurs in this polymer down to -2.7 V (vs. Ag/Ag+) in a non-destructive way with the characteristic development of the omega3 transition as a function of the doping level. In situ electronic transport studies revealed a high conductivity of the n-doped polymer which implies high mobility of the negatively charged carriers in the freshly doped PMOThOD film electrodes. An increase in the cathodic polarization, long-term cycling of the film electrodes, especially of higher thickness, results in a growing contribution of the negatively charged carriers trapping to the redox properties of the PMOThOD. The trapping of the charged carriers reduces gradually the electronic conductance of the PMOThOD film, but its effect on the redox-capacity of the film (in a typical scan rates range up to 50 mV s(-1)) is only minor.

In-situ spectroscopic investigations of the redox behavior of poly(indole-5-carboxylic-acid) modified electrodes in acidic aqueous solutions.

The oxidation of electrochemically grown poly(indole-5-carboxylic-acid) (P5CO2H) and its spectroscopic properties have been studied by in-situ spectroelectrochemical techniques. The purpose of this paper is to characterize the different modifications on the P5CO2H backbone, induced by the electrochemical oxidation in aqueous acidic solution. We have identified, on the basis of Raman spectra, the vibrational modes associated with neutral and oxidized segments of polymer. It was shown that at least three chemically and optically different species (perhaps other products too) are produced in different potential regimes upon oxidation of this polymer. The results obtained also indicate that the molecular properties of this conducting polymer are better revealed by in-situ resonant spectra than by ex-situ infrared and Raman studies.

UV-vis and Raman spectroelectrochemical investigation of the redox behavior of poly(5-cyanoindole) in acidic aqueous solutions.

Spectroelectrochemical properties of conducting poly(5-cyanoindole) films deposited on indium tin oxide (ITO) and platinum electrodes are investigated using UV-vis and resonant Raman spectroscopies. The transitions from undoped to semi-conducting state of P5CN require the partial oxidation of the polymer to create radical-cations by insertion of charge-neutralizing anions into the polymer. In order to obtain detailed structural information from the vibrational spectra, it is necessary to know the vibrational modes of oxidation-sensitive bands. Vibrational assignments were made on the basis of the results obtained on polyindole and P5CN in acetonitrile solution. The drastic changes in optical absorption and Raman spectra observed at various stage of oxidation were explained by the conversions between at least three different structures. On the basis of the Raman spectra, we have identified the vibrational modes associated with neutral and polaronic segments. The perturbation associated with the coexistence of these polaronic segments has been described as a quinoid structure growing on the expense of the benzoid one. The results obtained indicate that the molecular properties of the conducting polymers at various stages of an oxidation are better revealed by in-situ Raman spectra than by ex-situ studies.

Effect of Molecular Weight on Spectroscopic and Spectroelectrochemical Properties of Regioregular Poly(3-hexylthiophene).

Using experimentally established sequence of extractions, we were able to fractionate regioregular poly(3-hexylthiophene) (R-P3HT) into four fractions differing significantly in their molecular weight (Mn) and exhibiting low polydispersity coefficients. 1H NMR analysis of low molecular fractions enabled us to propose the dominant chain termination mechanisms and identify the sources of regioregularity defects. In particular, it turned out that the presence of small amounts of undesired isomer of 2-bromo-3-hexylthiophene, namely, 2-bromo-4-hexylthiophene, strongly influences the molecular weight and to a much lesser extent the regioregularity of the polymer obtained via Grignard type polycondensation. In the reaction with the growing chain, 2-bromo-4-hexylthiophene either causes its termination, lowering in this manner the molecular weight of the resulting polymer, or introduces regioregularity defects of TT-HH (TT = tail to tail; HH = head to head) type. The average conjugation length in R-P3HT increases with the increase of Mn as manifested by a bathochromic shift of the lambdamax and the appearance of the vibrational structure in the UV-vis-near-IR spectra of the fractions of higher molecular weight. This conclusion is supported by FTIR data. The onset of the oxidative doping of R-P3HT shifts to lower potentials with the increase of the molecular weight as evidenced by cyclic voltammetry and UV-vis-near-IR spectroelectrochemistry.

Future potential, phase I: nurse practitioners look at themselves.

Nurse practitioners identified as successful were interviewed to evaluate factors related to the viability of nurse practitioners in the health care system. The interviewees believed they were successful because they provided a nursing dimension of primary care, developed strategies to market themselves and their services, collaborated with physicians who saw them as colleagues, and had certain personality characteristics. In addition, the interviewees suggested strategies to enhance practice and potential nurse practitioner roles. These results suggest further research in two areas: investigation of health care administrators and management to solicit their ideas about the future strategic issues for the development of nurse practitioner roles and a broader, more formal survey of nurse practitioners regarding their success in the marketplace.