Novel materials for direct X-ray detectors based on semiconducting organic polymers

Conventional inorganic materials for x-ray radiation sensors suffer from several drawbacks, including their inability to cover large curved areas, me- chanical sti ffness, lack of tissue-equivalence and toxicity. Semiconducting organic polymers represent an alternative and have been employed as di- rect photoconversion material in organic diodes. In contrast to inorganic detector materials, polymers allow low-cost and large area fabrication by sol- vent based methods. In addition their processing is compliant with fexible low-temperature substrates. Flexible and large-area detectors are needed for dosimetry in medical radiotherapy and security applications. The objective of my thesis is to achieve optimized organic polymer diodes for fexible, di- rect x-ray detectors. To this end polymer diodes based on two different semi- conducting polymers, polyvinylcarbazole (PVK) and poly(9,9-dioctyluorene) (PFO) have been fabricated. The diodes show state-of-the-art rectifying be- haviour and hole transport mobilities comparable to reference materials. In order to improve the X-ray stopping power, high-Z nanoparticle Bi2O3 or WO3 where added to realize a polymer-nanoparticle composite with opti- mized properities. X-ray detector characterization resulted in sensitivties of up to 14 uC/Gy/cm2 for PVK when diodes were operated in reverse. Addition of nanoparticles could further improve the performance and a maximum sensitivy of 19 uC/Gy/cm2 was obtained for the PFO diodes. Compared to the pure PFO diode this corresponds to a five-fold increase and thus highlights the potentiality of nanoparticles for polymer detector design. In- terestingly the pure polymer diodes showed an order of magnitude increase in sensitivity when operated in forward regime. The increase was attributed to a different detection mechanism based on the modulation of the diodes conductivity

Costs of publicly provided maternity services in Rosario, Argentina

This material is posted here with permission of the publishers, Instituto Nacional de Salud Pública. Internal or personal use of this material is permitted. However, permission to reprint/republish this material must be obtained from the Publisher.Objective. This study estimates the costs of maternal health services in Rosario, Argentina. Material and Methods. The rovider costs (US$1999) of antenatal care, a normal vaginal delivery and a caesarean section, were evaluated retrospectively in two municipal hospitals. The cost of an antenatal visit was evaluated in two health centres and the patient costs associated with the visit were evaluated in a hospital and a health centre. Results. The average cost per hospital day is$114.62. The average cost of a caesarean section ($525.57) is five times greater than that of a normal vaginal delivery ($105.61). A normal delivery costs less at the general hospital and a c-section less at the aternity hospital. The average cost of an antenatal visit is $31.10. The provider cost is lower at the health centre than at the hospital. Personnel accounted for 72-94$4.70. Direct costs are minimal compared to indirect costs of travel and waiting time. Conclusions. These results suggest the potential for increasing the efficiency of resource use by promoting antenatal care visits at the primary level. Women could also benefit from reduced travel and waiting time. Similar benefits could accrue to the provider by encouraging normal delivery at general hospitals, and complicated deliveries at specialised maternity hospitals.Josephine Borghi is funded by the Department for International Development through the Maternal Health Programme at the London School of Hygiene and Tropical Medicine. This project was conducted for and funded by the Human Reproduction Programme at WHO, Geneva

Selective versus routine use of episiotomy for vaginal birth.

Background Some clinicians believe that routine episiotomy, a surgical cut of the vagina and perineum, will prevent serious tears during childbirth. On the other hand, an episiotomy guarantees perineal trauma and sutures. Objectives To assess the effects on mother and baby of a policy of selective episiotomy ('only if needed') compared with a policy of routine episiotomy ('part of routine management') for vaginal births. Search methods We searched Cochrane Pregnancy and Childbirth's Trials Register (14 September 2016) and reference lists of retrieved studies. Selection criteria Randomised controlled trials (RCTs) comparing selective versus routine use of episiotomy, irrespective of parity, setting or surgical type of episiotomy. We included trials where either unassisted or assisted vaginal births were intended. Quasi-RCTs, trials using a cross-over design or those published in abstract form only were not eligible for inclusion in this review. Data collection and analysis Two authors independently screened studies, extracted data, and assessed risk of bias. A third author mediated where there was no clear consensus. We observed good practice for data analysis and interpretation where trialists were review authors. We used fixed-effect models unless heterogeneity precluded this, expressed results as risk ratios (RR) and 95% confidence intervals (CI), and assessed the certainty of the evidence using GRADE. Main results This updated review includes 12 studies (6177 women), 11 in women in labour for whom a vaginal birth was intended, and one in women where an assisted birth was anticipated. Two were trials each with more than 1000 women (Argentina and the UK), and the rest were smaller (from Canada, Germany, Spain, Ireland, Malaysia, Pakistan, Columbia and Saudi Arabia). Eight trials included primiparous women only, and four trials were in both primiparous and multiparous women. For risk of bias, allocation was adequately concealed and reported in nine trials; sequence generation random and adequately reported in three trials; blinding of outcomes adequate and reported in one trial, blinding of participants and personnel reported in one trial. For women where an unassisted vaginal birth was anticipated, a policy of selective episiotomy may result in 30% fewer women experiencing severe perineal/vaginal trauma (RR 0.70, 95% CI 0.52 to 0.94; 5375 women; eight RCTs; low-certainty evidence). We do not know if there is a difference for blood loss at delivery (an average of 27 mL less with selective episiotomy, 95% CI from 75 mL less to 20 mL more; two trials, 336 women, very low-certainty evidence). Both selective and routine episiotomy have little or no effect on infants with Apgar score less than seven at five minutes (four trials, no events; 3908 women, moderate-certainty evidence); and there may be little or no difference in perineal infection (RR 0.90, 95% CI 0.45 to 1.82, three trials, 1467 participants, low-certainty evidence). For pain, we do not know if selective episiotomy compared with routine results in fewer women with moderate or severe perineal pain (measured on a visual analogue scale) at three days postpartum (RR 0.71, 95% CI 0.48 to 1.05, one trial, 165 participants, very low-certainty evidence). There is probably little or no difference for long-term (six months or more) dyspareunia (RR1.14, 95% CI 0.84 to 1.53, three trials, 1107 participants, moderate-certainty evidence); and there may be little or no difference for long-term (six months or more) urinary incontinence (average RR 0.98, 95% CI 0.67 to 1.44, three trials, 1107 participants, low-certainty evidence). One trial reported genital prolapse at three years postpartum. There was no clear difference between the two groups (RR 0.30, 95% CI 0.06 to 1.41; 365 women; one trial, low certainty evidence). Other outcomes relating to long-term effects were not reported (urinary fistula, rectal fistula, and faecal incontinence). Subgroup analyses by parity (primiparae versus multiparae) and by surgical method (midline versus mediolateral episiotomy) did not identify any modifying effects. Pain was not well assessed, and women's preferences were not reported. One trial examined selective episiotomy compared with routine episiotomy in women where an operative vaginal delivery was intended in 175 women, and did not show clear difference on severe perineal trauma between the restrictive and routine use of episiotomy, but the analysis was underpowered

World in a text, words in context: enhancing the role of literature in language learning

This thesis aims to provide a qualitative analysis of the different ways in which students perceive, approach, and learn from literary texts in a non native language (L2). The thesis situates the research in the context of the debate concerning the possible roles of L2 literature by outlining the main arguments, approaches and descriptions of Ll and L2 literature. Barely touched by this literature, however, are L2 learners' experiences of L2 literature and L2 learning models and methods for analysing students' perceptions and approaches to the study of literature. This forms the focus of the research reported here. For the research I conducted as both researcher and educator at the Australian National University I adopted a cross-sectional design. This allowed me to undertake the research in stages, with different groups of students of Italian, to investigate: 1) what students are actually thinking about and doing with L2 literary texts; and 2) ways of improving learning for all L2 students studying L2 literature. Following a preliminary investigation into students' perceptions of literature in 1998, I conducted two main studies in 1999 and 2000. In 1998 I had found that many students perceived literature in general as entertainment and, vice versa, L2 literature mainly as difficult language learning. Study 1 (1999) therefore investigated further students' perceptions of L2 literature and also their approaches to the study of literature. The major finding of study 1 was an association between perceptions of literature and approaches to the study of L2 literary texts and learning. Complex perceptions of literature and favourable attitudes towards L2 literature were related to integrated deep study approaches which led to advanced learning achievements. Conversely, more limited learning achievements were linked to less complex perceptions of literature, less favourable views of L2 literature and surface approaches to study. Study 2 (2000) investigated a novel pedagogic approach based on key principles of phenomenography (awareness; reflective variation; change)and hermeneutics (the class as a learning community), and a repeated reading method designed to elicit complex understandings of L2 literary texts. Findings from study 2 are that students' awareness of their approach to reading literature, introduction of repeated readings of the same literature,and class reflection on variation in students' response to literature are key elements in expanding students' abilities and learning. These findings highlight that students' experiences of subject matter are a crucial factor in literature and language education. Therefore, the role of L2 literature can be enhanced only if students' learning experiences of L2 literature are enhanced, and this can only happen if we,the educators and researchers, become aware of them and include them in our research and pedagogical practice

Selection of mothers with increased risk of delivery low birthweight newborns at a public maternity hospital in Rosario, Argentina

A retrospective analysis was made of births occurring over a six-month period at apublic maternity hospital in the city of Rosario, Argentina, with a view to planningactions reducing the likelihood of low birthweight deliveries. Fifteen risk factorswere assessed. While a history of delivering a low birthweight infant was theleading risk factor for both intrauterine growth retardation and preterm delivery,the other leading risk factors for these two types of low birthweight newbornsdiffered. Many variables relating to socioeconomic and cultural levels that havetraditionally been considered risk factors for low birthweight did not display anysignificant association.Risk calculations for the study population were made using data gathered at thepatients? first prenatal checkup. These calculations indicated that mothers with oneor more of four leading risk factors (a history of deliver&g low birthweight newborns, smoking more than two cigarettes a day, weighing less than 46 kg, and beingless than 148 cm tall) constituted only 26.6% of the study populati.on but accountedfor 51.6% of the low birthweight deliveries. Such screening can provide an effectiveway of selecting high-risk mothers, and simple analyses of this sort are essential inplanning health actions relating to low birthweight deliveries.Fil: Belizan, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; Argentina. Centro Rosarino de Estudios Perinatales; ArgentinaFil: Nardin, Juan Carlos. Centro Rosarino de Estudios Perinatales; ArgentinaFil: Carroli, Guillermo. Centro Rosarino de Estudios Perinatales; ArgentinaFil: Campodonico, Liana. Centro Rosarino de Estudios Perinatales; Argentin

Obstetric transition in the World Health Organization Multicountry Survey on Maternal and Newborn Health: exploring pathways for maternal mortality reduction.

Objective: To test whether the proposed features of the Obstetric Transition Model-a theoretical framework that may explain gradual changes that countries experience as they eliminate avoidable maternal mortality-are observed in a large, multicountry, maternal and perinatal health database; and to discuss the dynamic process of maternal mortality reduction using this model as a theoretical framework. Methods: This was a secondary analysis of a cross-sectional study by the World Health Organization that collected information on more than 300 000 women who delivered in 359 health facilities in 29 countries in Africa, Asia, Latin America, and the Middle East, during a 2-4-month period in 2010-2011. The ratios of Potentially Life-Threatening Conditions, Severe Maternal Outcomes, Maternal Near Miss, and Maternal Death were estimated and stratified by stages of obstetric transition. The characteristics of each stage are defined. Results: Data from 314 623 women showed that female fertility, indirectly estimated by parity, was higher in countries at a lower obstetric transition stage, ranging from a mean of 3 children in Stage II to 1.8 children in Stage IV. Medicalization increased with obstetric transition stage. In Stage IV, women had 2.4 times the cesarean deliveries (15.3% in Stage II and 36.7% in Stage IV) and 2.6 times the labor inductions (7.1% in Stage II and 18.8% in Stage IV) as women in Stage II. The mean age of primiparous women also increased with stage. The occurrence of uterine rupture had a decreasing trend, dropping by 5.2 times, from 178 to 34 cases per 100 000 live births, as a country transitioned from Stage II to IV. Conclusions: This analysis supports the concept of obstetric transition using multicountry data. The Obstetric Transition Model could provide justification for customizing strategies for reducing maternal mortality according to a country\u27s stage in the obstetric transition

The World Health Organization Fetal Growth Charts: A Multinational Longitudinal Study of Ultrasound Biometric Measurements and Estimated Fetal Weight.

BACKGROUND: Perinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW) and common ultrasound biometric measurements intended for worldwide use. METHODS AND FINDINGS: We conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand) recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown-rump length measured at 8-13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study. At study entry, median maternal age was 28 y (interquartile range [IQR] 25-31), median height was 162 cm (IQR 157-168), median weight was 61 kg (IQR 55-68), 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487-2,222). The median pregnancy duration was 39 wk (IQR 38-40) although there were significant differences between countries, the largest difference being 12 d (95% CI 8-16). The median birthweight was 3,300 g (IQR 2,980-3,615). There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had intrauterine death. The 8,203 sets of ultrasound measurements were scrutinized for outliers and leverage points, and those measurements taken at 14 to 40 wk were selected for analysis. A total of 7,924 sets of ultrasound measurements were analyzed by quantile regression to establish longitudinal reference intervals for fetal head circumference, biparietal diameter, humerus length, abdominal circumference, femur length and its ratio with head circumference and with biparietal diameter, and EFW. There was asymmetric distribution of growth of EFW: a slightly wider distribution among the lower percentiles during early weeks shifted to a notably expanded distribution of the higher percentiles in late pregnancy. Male fetuses were larger than female fetuses as measured by EFW, but the disparity was smaller in the lower quantiles of the distribution (3.5%) and larger in the upper quantiles (4.5%). Maternal age and maternal height were associated with a positive effect on EFW, particularly in the lower tail of the distribution, of the order of 2% to 3% for each additional 10 y of age of the mother and 1% to 2% for each additional 10 cm of height. Maternal weight was associated with a small positive effect on EFW, especially in the higher tail of the distribution, of the order of 1.0% to 1.5% for each additional 10 kg of bodyweight of the mother. Parous women had heavier fetuses than nulliparous women, with the disparity being greater in the lower quantiles of the distribution, of the order of 1% to 1.5%, and diminishing in the upper quantiles. There were also significant differences in growth of EFW between countries. In spite of the multinational nature of the study, sample size is a limiting factor for generalization of the charts. CONCLUSIONS: This study provides WHO fetal growth charts for EFW and common ultrasound biometric measurements, and shows variation between different parts of the world

Compliance with focused antenatal care services: do health workers in rural Burkina Faso, Uganda and Tanzania perform all ANC procedures?

\ud \ud To assess health workers' compliance with the procedures set in the focused antenatal care (ANC) guidelines in rural Uganda, Tanzania and Burkina Faso; to compare the compliance within and among the three study sites; and to appraise the logistic and supply of the respective health facilities (HF). The cross-sectional study was conducted in the rural HF in three African countries. This descriptive observational study took place in HF in Nouna, Burkina Faso (5), Iganga, Uganda (6) and Rufiji, Tanzania (7). In total, 788 ANC sessions and service provisions were observed, the duration of each ANC service provision was calculated, and the infrastructures of the respective HF were assessed. Health workers in all HF performed most of the procedures but also omitted certain practices stipulated in the focused ANC guidelines. There was a substantial variation in provision of ANC services among HF within and among the country sites. The findings also revealed that the duration of first visits was <15 min and health workers spent even less time in subsequent visits in all three sites. Reagents for laboratory tests and drugs as outlined in the focus ANC guidelines were often out of stock in most facilities. Health workers in all three country sites failed to perform all procedures stipulated in the focused ANC guideline; this could not be always explained by the lack of supplies. It is crucial to point out the necessity of the core procedures of ANC repeatedly