Micromechanical model for isolated polymer-colloid clusters under tension

Binary polymer-colloid (PC) composites form the majority of biological load-bearing materials. Due to the abundance of the polymer and particles, and their simple aggregation process, PC clusters are used broadly by nature to create biomaterials with a variety of functions. However, our understanding of the mechanical features of the clusters and their load transfer mechanism is limited. Our main focus in this paper is the elastic behavior of close-packed PC clusters formed in the presence of polymer linkers. Therefore, a micromechanical model is proposed to predict the constitutive behavior of isolated polymer-colloid clusters under tension. The mechanical response of a cluster is considered to be governed by a backbone chain, which is the stress path that transfers most of the applied load. The developed model can reproduce the mean behavior of the clusters and is not dependent on their local geometry. The model utilizes four geometrical parameters for defining six shape descriptor functions which can affect the geometrical change of the clusters in the course of deformation. The predictions of the model are benchmarked against an extensive set of simulations by coarse-grained-Brownian dynamics, where clusters with different shapes and sizes were considered. The model exhibits good agreement with these simulations, which, besides its relative simplicity, makes the model an excellent add-on module for implementation into multiscale models of nanocomposites.National Science Foundation (U.S.) (CAREER Award DMR-1054671)MIT International Science and Technology Initiatives (MISTI-Germany)United States. Dept. of Transportation. UTC Center for Highway Pavement Preservatio

Mammography in asymptomatic women aged 40-49 years

OBJECTIVE To assess findings of mammography of and interventions resulting from breast cancer screening in women aged 40-49 years with no increased risk (typical risk) of breast cancer. METHODS This cross-sectional study evaluated women aged 40-49 years who underwent mammography screening in a mastology reference center in Recife, PE, Northeastern Brazil, between January 2010 and October 2011. Women with breast-related complaints, positive findings in the physical examination, or high risk of breast cancer were excluded. RESULTS The 1,000 mammograms performed were classified into the following Breast Imaging-Reporting and Data System (BI-RADS) categories BI-RADS 0, 232; BI-RADS 1, 294; BI-RADS 2, 294; BI-RADS 3, 16; BI-RADS 4A, 2; BI-RADS 5, 1. There was one case of grade II invasive ductal carcinoma and various interventions, including 469 ultrasound scans, 53 referrals to mastologists, 11 cytological examinations, and 8 biopsies. CONCLUSIONS Mammography screening in women aged 40-49 years with typical risk of breast cancer led to the performance of other interventions. However, it also resulted in increased costs without demonstrable efficacy in decreasing mortality.OBJETIVO Avaliar os achados mamográficos e as intervenções decorrentes do rastreamento em mulheres de 40 a 49 anos de idade com risco habitual para o câncer de mama. MÉTODOS Estudo transversal com mulheres de 40 a 49 anos, submetidas ao rastreamento mamográfico em centro de referência em mastologia, em Recife, PE, de janeiro de 2010 a outubro de 2011. Foram excluídas mulheres com queixas mamárias, alterações no exame físico e com alto risco para câncer de mama. RESULTADOS Das 1.000 mamografias realizadas, 232 foram BI-RADS 0, 454 BI-RADS 1, 294 BI-RADS 2, 16 BI-RADS 3, duas BI-RADS 4A, uma BI-RADS 4C e uma BI-RADS 5. Observou-se um único caso de carcinoma ductal invasivo grau II e várias intervenções: 469 ultrassonografias, 53 encaminhamentos para a mastologia, 11 citologias e oito biópsias. CONCLUSÕES O rastreamento mamográfico em mulheres de 40 a 49 anos com risco habitual para o câncer de mama leva a outras intervenções e, assim, ao aumento dos custos com eficácia não mostrada para redução da mortalidade

Factors associated with severe maternal morbidity and near miss in the São FranciscoValley, Brazil: a retrospective, cohort study

BACKGROUND: Maternal mortality remains a major public health issue worldwide, with persistent high rates prevailing principally in underdeveloped countries. The objective of this study was to determine the risk factors for severe maternal morbidity and near miss (SMM/NM) in pregnant and postpartum women at the maternity ward of the Dom Malan Hospital, Petrolina, in northeastern Brazil. METHODS: A retrospective, cohort study was conducted to evaluate the sociodemographic and obstetric characteristics of the women. Patients who remained hospitalized at the end of the study period were excluded. Risk ratios (RR) and their respective 95% confidence intervals (95% CI) were calculated as a measure of relative risk. Hierarchical multiple logistic regression was also performed. Two-tailed p-values were used for all the tests and the significance level adopted was 5%. RESULTS: A total of 2,291 pregnant or postpartum women receiving care between May and August, 2011 were included. The frequencies of severe maternal morbidity and near miss were 17.5% and 1.0%, respectively. Following multivariate analysis, the factors that remained significantly associated with an increased risk of SMM/NM were a Cesarean section in the current pregnancy (OR: 2.6; 95% CI: 2.0 – 3.3), clinical comorbidities (OR: 3.4; 95% CI: 2.5 – 4.4), having attended fewer than six prenatal visits (OR: 1.1; 95% CI: 1.01 – 1.69) and the presence of the third delay (i.e. delay in receiving care at the health facility) (OR: 13.3; 95% CI: 6.7 – 26.4). CONCLUSIONS: The risk of SMM/NM was greater in women who had been submitted to a Cesarean section in the current pregnancy, in the presence of clinical comorbidities, fewer prenatal visits and when the third delay was present. All these factors could be minimized by initiating a broad debate on healthcare policies, introducing preventive measures and improving the training of the professionals and services providing obstetric care

Anestesia combinada e métodos não farmacológicos para alívio da dor durante o trabalho de parto e satisfação materna: ensaio clínico randomizado

OBJECTIVE: The objective of this study was to compare maternal satisfaction with childbirth according to whether or not combined spinal-epidural anesthesia (CSE) of pain relief was used during labor. METHODS: A randomized, open clinical trial was performed with 70 pregnant women, 35 of whom received CSE anesthesia while 35 received only non-pharmacological forms of pain relief during labor. The variables evaluated were visual analogue scale (VAS) pain score, maternal satisfaction with the technique of pain relief used during childbirth and with delivery, the patient's intention to request the same technique in a subsequent delivery, and loss of control during delivery. RESULTS: VAS pain score decreased significantly in patients receiving CSE during vaginal delivery. Furthermore, maternal satisfaction with the technique of pain relief and with delivery was higher in the CSE group, and around 97% of the patients would repeat the same technique at future deliveries compared to 82.4% of the women in the group using only non-pharmacological methods. With respect to the women's impressions of their control during delivery, approximately half the women in both groups felt that they had lost control at some point during the process. CONCLUSION: The use of CSE was associated with a significant reduction in VAS pain scores during delivery and with greater maternal satisfaction with the pain relief method and with the childbirth process.OBJETIVOS: Comparar a satisfação materna com o processo do nascimento de acordo com a realização ou não de métodos farmacológicos para alívio da dor do trabalho de parto. MÉTODOS: Realizou-se um ensaio clínico randomizado com 70 parturientes, 35 das quais receberam anestesia combinada (raquidiana e peridural associadas) e 35 receberam métodos não farmacológicos para alívio da dor durante o parto vaginal. As variáveis estudadas foram: escores de dor pela Escala Visual Analógica (EVA), satisfação materna com a técnica analgésica e com o parto, desejo de repetir a técnica analgésica em parto posterior e perda do controle sobre o parto. A análise estatística foi realizada no programa Epi-Info 3.5.3, com base na intenção de tratar. RESULTADOS: Pacientes recebendo anestesia combinada (AC) durante o parto vaginal experimentaram uma diminuição significativa dos escores da EVA e maior satisfação materna com a técnica analgésica e com o parto. A maioria das parturientes, cerca de 97% do grupo da anestesia combinada, repetiu a técnica em partos futuros, contra 82,4% do grupo dos métodos não farmacológicos. No que diz respeito ao sentimento de controle do parto, aproximadamente metade das parturientes dos dois grupos sentiu que em algum momento do parto perdeu o controle deste, não havendo diferença significativa entre os grupos. CONCLUSÃO: O uso da AC está associado a uma significante diminuição dos escores da dor durante o parto, e maior satisfação materna com a técnica analgésica e com o parto.11211

Electrical conductivity during incipient melting in the oceanic low-velocity zone

International audienceThe low-viscosity layer in the upper mantle, the asthenosphere, is a requirement for plate tectonics1. The seismic low velocities and the high electrical conductivities of the asthenosphere are attributed either to subsolidus, water-related defects in olivine minerals2, 3, 4 or to a few volume per cent of partial melt5, 6, 7, 8, but these two interpretations have two shortcomings. First, the amount of water stored in olivine is not expected to be higher than 50 parts per million owing to partitioning with other mantle phases9 (including pargasite amphibole at moderate temperatures10) and partial melting at high temperatures9. Second, elevated melt volume fractions are impeded by the temperatures prevailing in the asthenosphere, which are too low, and by the melt mobility, which is high and can lead to gravitational segregation11, 12. Here we determine the electrical conductivity of carbon-dioxide-rich and water-rich melts, typically produced at the onset of mantle melting. Electrical conductivity increases modestly with moderate amounts of water and carbon dioxide, but it increases drastically once the carbon dioxide content exceeds six weight per cent in the melt. Incipient melts, long-expected to prevail in the asthenosphere10, 13, 14, 15, can therefore produce high electrical conductivities there. Taking into account variable degrees of depletion of the mantle in water and carbon dioxide, and their effect on the petrology of incipient melting, we calculated conductivity profiles across the asthenosphere for various tectonic plate ages. Several electrical discontinuities are predicted and match geophysical observations in a consistent petrological and geochemical framework. In moderately aged plates (more than five million years old), incipient melts probably trigger both the seismic low velocities and the high electrical conductivities in the upper part of the asthenosphere, whereas in young plates4, where seamount volcanism occurs6, a higher degree of melting is expected

Аудіовізуальні особливості пейзажистики ранніх балад Т. Шевченка

(uk) У статті осмислюються аудіовізуальні особливості пейзажотворення в ранній творчості Тараса Шевченка. На матеріалі балад «Причинна», «Тополя», «Утоплена» розглядається сугестивна майстерність поета, здатність до живописання словом, створення ілюзії присутності реципієнта в художньому світі твору.(en) Audiovisual features of the landscape descriptionin the early Shevchenko’s ballads. The paper interprets audiovisual features of the landscape description in the early works of Taras Shevchenko. Suggestive poetic skill, capability of word skill, creating the illusion of recipient’s presence in the worldof the art works are considered on the material of the ballads "The Girl under a Spell", "Poplar", "A Drowned Girl"