Investigation of material properties of yttria-stabilised zirconia using experimental techniques and first-principles calculations

Zirconia (ZrO2) exists in a monoclinic phase at ambient temperature and pressure. Increasing the temperature of zirconia brings about a transition from the monoclinic to a tetragonal phase, and then the formation of a cubic phase. Yttria (Y2O3) can be added to zirconia in order to stabilise the high temperature phases, resulting in forms of tetragonal and cubic zirconia that are stable at ambient temperature. These materials are ceramics and are known collectively as yttria-stabilised zirconia (YSZ). The primary aim of this thesis is to investigate the structural, electronic, vibrational and mechanical properties of zirconia in its three ambient pressure polymorphs, together with YSZ for a range of yttria concentrations. Firstly, short-range order is investigated by medium energy x-ray photoemission spectroscopy for a YSZ sample with 8-9 mol % Y2O3, in combination with first-principles density-functional theory (DFT) calculations for two YSZ structural models with 10.35 mol % Y2O3 and shows that both structural models have short-range order that agrees with results from XPS experiments. Secondly, long-range order is analysed by comparing results of neutron scattering experiments for crystals of the same yttria concentration, with the same two YSZ models. Comparison with calculated vibrational density of states for the two structural models indicates the occurrence of long-range order for one of the structures in agreement with the experimental result. Thirdly, these calculations are extended to a full study of the electronic partial density of states and vibrational density of states for ZrO2, and for YSZ models with 10.35, 14, 17, 20 and 40 mol % Y2O3. Lastly, mechanical properties are investigated through first-principles calculations of the bulk modulus, shear modulus, Young's modulus and Poisson's ratio for the three ambient-pressure phases of ZrO2 and compared to existing available experimental results. The ideal strength of cubic ZrO2 is calculated for strains in the [100], [110] and [111] directions and for YSZ with concentrations of 6.67 mol % and 14.29 mol % Y2O3 for strains in the [100] and [110] directions. The ideal strength is also calculated for YSZ with concentration of 6.67 mol % Y2O3 co-doped with titanium, manganese, calcium or nickel

The association between adverse pregnancy outcomes and non-viral genital pathogens among women living in sub-Saharan Africa: a systematic review

Adverse pregnancy outcomes are the main causes of maternal and neonatal morbidity and mortality, including long-term physical and psychological sequelae. These events are common in low- and middle-income countries, particularly in Sub Saharan Africa, despite national efforts. Maternal infections can cause complications at any stage of pregnancy and contribute to adverse outcomes. Among infections, those of the genital tract are a major public health concern worldwide, due to limited availability of prevention, diagnosis and treatment approaches. This applies even to treatable infections and holds true especially in Sub-Saharan Africa. As late as 2017, the region accounted for 40% of all reported treatable non-viral genital pathogens worldwide, many of which have been independently associated with various adverse pregnancy outcomes, and that include Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Treponema pallidum. Two databases (PubMed and Embase) were examined to identify eligible studies published up to October 2022. This study reviewed findings on the association between infections by treatable non-viral genital pathogens during pregnancy and adverse pregnancy outcomes among women living in Sub-Saharan Africa. Articles' title and abstract were screened at first using keywords as “sexually transmitted infections”, “non-viral”, “adverse pregnancy outcome”, “Africa”, “sub-Saharan Africa”, “pregnant women”, “pregnancy”, and “pregnancy outcome”. Subsequently, according to the eligibility criteria, potential articles were read in full. Results showed that higher risk of preterm birth is associated with Treponema pallidum, Chlamydia trachomatis and Candida albicans infections. Additionally, rates of stillbirth, neonatal death, low birth weight and intrauterine growth restriction are also associated with Treponema pallidum infection. A better insight on the burden of non-viral genital pathogens and their effect on pregnancy is needed to inform antenatal care guidelines and screening programs, to guide the development of innovative diagnostic tools and other strategies to minimize transmission, and to prevent short- and long-term complications for mothers and children

Seeing blue: negotiating the politics of Avatar media activism

This thesis examines how the Hollywood blockbuster Avatar (2009) has been taken-up in media activism directed towards Indigenous struggles against imperialism. It assumes the importance of locating this phenomenon within the discursive and material regimes that mediate, enable, and constrain it. I therefore offer a contextualised analysis of the film and media relating to its appropriation, which focuses on the representational practices and structural mechanisms that inform the production, circulation, and reception of the texts. This approach emphasises the tensions and contradictions that underpin activists’ relationship to the media they mobilise. Such contradictions are particularly apparent in relation to the politics of race that shape Avatar, the Indigenous activism that references it, and the media regimes that make this possible. The very forces that marginalise Indigenous voices empower auteur James Cameron to speak on their behalf and to be heard. Activists must also negotiate the tension between co-opting media spectacle and being commercialised as spectacle. However, refusing a simple critique of the representations activists deploy as media spectacles, I argue for a model that foregrounds the alliances that they seek to engender. Drawing on the work of feminist scholars Oliver (2001) and Deslandes (2010), I signal a theoretical approach that focuses on how the mediated spectator relates to such representations and insists on the spectator’s responsibility to respond. Acknowledging that the tensions that animate Avatar media activism can be both constrictive and creative, this project seeks a model that maximises the potential for the latter. It thus resists the paralysis of activism that can come with critiquing how we fight for the world we imagine

Midtrimester preterm prelabour rupture of membranes (PPROM):expectant management or amnioinfusion for improving perinatal outcomes (PPROMEXIL - III trial)

BACKGROUND: Babies born after midtrimester preterm prelabour rupture of membranes (PPROM) are at risk to develop neonatal pulmonary hypoplasia. Perinatal mortality and morbidity after this complication is high. Oligohydramnios in the midtrimester following PPROM is considered to cause a delay in lung development. Repeated transabdominal amnioinfusion with the objective to alleviate oligohydramnios might prevent this complication and might improve neonatal outcome. METHODS/DESIGN: Women with PPROM and persisting oligohydramnios between 16 and 24 weeks gestational age will be asked to participate in a multi-centre randomised controlled trial. Intervention: random allocation to (repeated) abdominal amnioinfusion (intervention) or expectant management (control). The primary outcome is perinatal mortality. Secondary outcomes are lethal pulmonary hypoplasia, non-lethal pulmonary hypoplasia, survival till discharge from NICU, neonatal mortality, chronic lung disease (CLD), number of days ventilatory support, necrotizing enterocolitis (NEC), periventricular leucomalacia (PVL) more than grade I, severe intraventricular hemorrhage (IVH) more than grade II, proven neonatal sepsis, gestational age at delivery, time to delivery, indication for delivery, successful amnioinfusion, placental abruption, cord prolapse, chorioamnionitis, fetal trauma due to puncture. The study will be evaluated according to intention to treat. To show a decrease in perinatal mortality from 70% to 35%, we need to randomise two groups of 28 women (two sided test, β-error 0.2 and α-error 0.05). DISCUSSION: This study will answer the question if (repeated) abdominal amnioinfusion after midtrimester PPROM with associated oligohydramnios improves perinatal survival and prevents pulmonary hypoplasia and other neonatal morbidities. Moreover, it will assess the risks associated with this procedure. TRIAL REGISTRATION: NTR3492 Dutch Trial Register (http://www.trialregister.nl)

Screening of chorioamnionitis using volatile organic compound detection in exhaled breath: a pre-clinical proof of concept study

Chorioamnionitis is a major risk factor for preterm birth and an independent risk factor for postnatal morbidity for which currently successful therapies are lacking. Emerging evidence indicates that the timing and duration of intra-amniotic infections are crucial determinants for the stage of developmental injury at birth. Insight into the dynamical changes of organ injury after the onset of chorioamnionitis revealed novel therapeutic windows of opportunity. Importantly, successful development and implementation of therapies in clinical care is currently impeded by a lack of diagnostic tools for early (prenatal) detection and surveillance of intra-amniotic infections. In the current study we questioned whether an intra-amniotic infection could be accurately diagnosed by a specific volatile organic compound (VOC) profile in exhaled breath of pregnant sheep. For this purpose pregnant Texel ewes were inoculated intra-amniotically with Ureaplasma parvum and serial collections of exhaled breath were performed for 6 days. Ureaplasma parvum infection induced a distinct VOC-signature in expired breath of pregnant sheep that was significantly different between day 0 and 1 vs. day 5 and 6. Based on a profile of only 15 discriminatory volatiles, animals could correctly be classified as either infected (day 5 and 6) or not (day 0 and 1) with a sensitivity of 83% and a specificity of 71% and an area under the curve of 0.93. Chemical identification of these distinct VOCs revealed the presence of a lipid peroxidation marker nonanal and various hydrocarbons including n-undecane and n-dodecane. These data indicate that intra-amniotic infections can be detected by VOC analyses of exhaled breath and might provide insight into temporal dynamics of intra-amniotic infection and its underlying pathways. In particular, several of these volatiles are associated with enhanced oxidative stress and undecane and dodecane have been reported as predictive biomarker of spontaneous preterm birth in humans. Applying VOC analysis for the early detection of intra-amniotic infections will lead to appropriate surveillance of these high-risk pregnancies, thereby facilitating appropriate clinical course of action including early treatment of preventative measures for pre-maturity-associated morbidities

RhoE Is Regulated by Cyclic AMP and Promotes Fusion of Human BeWo Choriocarcinoma Cells

Fusion of placental villous cytotrophoblasts with the overlying syncytiotrophoblast is essential for the maintenance of successful pregnancy, and disturbances in this process have been implicated in pathological conditions such as pre-eclampsia and intra-uterine growth retardation. In this study we examined the role of the Rho GTPase family member RhoE in trophoblast differentiation and fusion using the BeWo choriocarcinoma cell line, a model of villous cytotrophoblast fusion. Treatment of BeWo cells with the cell permeable cyclic AMP analogue dibutyryl cyclic AMP (dbcAMP) resulted in a strong upregulation of RhoE at 24h, coinciding with the onset of fusion. Using the protein kinase A (PKA)-specific cAMP analogue N6-phenyl-cAMP, and a specific inhibitor of PKA (14–22 amide, PKI), we found that upregulation of RhoE by cAMP was mediated through activation of PKA signalling. Silencing of RhoE expression by RNA interference resulted in a significant decrease in dbcAMP-induced fusion. However, expression of differentiation markers human chorionic gonadotrophin and placental alkaline phosphatase was unaffected by RhoE silencing. Finally, we found that RhoE upregulation by dbcAMP was significantly reduced under hypoxic conditions in which cell fusion is impaired. These results show that induction of RhoE by cAMP is mediated through PKA and promotes BeWo cell fusion but has no effect on functional differentiation, supporting evidence that these two processes may be controlled by separate or diverging pathways

STRIDER (Sildenafil TheRapy in dismal prognosis early onset fetal growth restriction): An international consortium of randomised placebo-controlled trials

Background: Severe, early-onset fetal growth restriction due to placental insufficiency is associated with a high risk of perinatal mortality and morbidity with long-lasting sequelae. Placental insufficiency is the result of abnormal formation and function of the placenta with inadequate remodelling of the maternal spiral arteries. There is currently no effective therapy available. Some evidence suggests sildenafil citrate may improve uteroplacental blood flow, fetal growth, and meaningful infant outcomes. The objective of the Sildenafil TheRapy In Dismal prognosis Early onset fetal growth Restriction (STRIDER) collaboration is to evaluate the effectiveness of sildenafil versus placebo in achieving healthy perinatal survival through the conduct of randomised clinical trials and systematic review including individual patient data meta-analysis.  Methods: Five national/bi-national multicentre randomised placebo-controlled trials have been launched. Women with a singleton pregnancy between 18 and 30 weeks with severe fetal growth restriction of likely placental origin, and where the likelihood of perinatal death/severe morbidity is estimated to be significant are included. Participants will receive either sildenafil 25 mg or matching placebo tablets orally three times daily from recruitment to 32 weeks gestation.  Discussion: The STRIDER trials were conceived and designed through international collaboration. Although the individual trials have different primary outcomes for reasons of sample size and feasibility, all trials will collect a standard set of outcomes including survival without severe neonatal morbidity at time of hospital discharge. This is a summary of all the STRIDER trial protocols and provides an example of a prospectively planned international clinical research collaboration. All five individual trials will contribute to a pre-planned systematic review of the topic including individual patient data meta-analysis

الخيط السري بين القديم والحديث في ﺍﻟﻔﻦ: مقابلة مع رافع الناصري / The Secret Thread between the Old and the New in Art: Interview with Rafa Al-Nasiry

[Rafa Al-Nasiry is a contemporary Iraqi artist, well-known for his painting and graphic art. He studied painting in Baghdad, graphic art in Beijing, and engraving in Lisbon. Fascinated by the possibilities of the Arabic alphabet and Chinese brush painting, he developed a fairly abstract style with symbolic overtones. His work whether in woodcuts, etching, or in acrylic is inspired by Mesopotamian motifs and Islamic aesthetics, rendered with modern dynamism. Interviewed by May Muzaffar, Iraqi art critic and poet, al-Nasiry discusses different stages of his artistic trajectory and the subtle ways in which traces of the old figure in his art. Illustrations ranging from 1962-2002 in the interview provide a glimpse of the development of his work. He combines innovative artistic techniques with his own philosophy of desing as central in plastic art. /‮رافع الناصرﻱ فنان عراقي معاصر اشتهر بأعماله في الرسم وفنون الحفر والطباعة (غرافيك)٠ درس فن الرسم في بغداد، ودرس فنون الحفر والطباعة في الصين، ثم في لشبونة٠ توصل إلى أسلوبه الخاص في الفن التجريدي عندما اكتشف سحر الحرف العربي وطواعيته في الرسم فأخضعه إلى مهاراته في استخدام الفرشاة والضربات اللونية التي اكتسبها من دراسته في الصين٠ تعكس أعمال الناصري، سواءً أكانت لوحات مرسومة بمادة الأكريلك أو مطبوعة (باستخدام الحفر على النحاس)، اهتماماته بحضارة وادي الرافدين على تعاقب حضاراتها بما في ذلك جماليات الفنون الإسلامية، فهو يستعير منها رموزه وعناصر تكويناته التي تتجلى في أسلوبه الحداثي المفعم بالحيوية٠ أجرت الشاعرة والناقدة التشكيلية مي مظفر مقابلة مع الفنان رافع الناصري تحدث فيها عن مراحل عمله المختلفة وتطور تجربته الفنية بدءاﹰ من مرحلته الأكاديمية التشخيصية٠ كما ننشر مع المقابلة مجموعة من الصور التي تمثل مراحل العمل خلال السنوات ٢٦٩١ - ٢٠٠٢، لإعطاء لمحة عن طبيعة تطور هذه الأعمال التي تجمع بين التقنيات الفنية المبتكرة، وفلسفته في العمل التي تتخذ من التصميم نقطة مر كزية في تنفيذ العمل الفني التشكيلي٠‬