bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodontal disease and adverse pregnancy outcomes: a systematic review
Authors: Xiong X , Buekens P , Fraser WD , Beck J , Offenbacher S
Published: January 2006

Background  Recent studies suggest that periodontal disease, as a source of subclinical and persistent infection, may induce systemic inflammatory responses that increase the risk of adverse pregnancy outcomes.

Objectives  To examine the existing evidence on the relationship between periodontal disease and adverse pregnancy outcomes.

Search strategy  Published studies identified via searches of the MEDLINE, EMBASE, CINAHL, and Current Contents full‐text databases.

Selection criteria  We identified and selected observational studies (i.e. case–control, cross‐sectional, and cohort) and nonrandomised controlled studies or randomised controlled trials that examined periodontal disease as a risk factor for adverse pregnancy outcomes.

Data collection and analysis  Odds ratios (OR) or risk ratios (RR) were extracted or calculated from the studies’ data. We calculated pooled effect size for two clinical controlled trials but not for the observational studies due to the heterogeneity in definitions for periodontal disease and adverse pregnancy outcomes across studies.

Main results  Twenty‐five studies (13 case–control, 9 cohort, and 3 controlled trials) were identified. The studies focused on preterm low birthweight, low birthweight, preterm birth, birthweight by gestational age, miscarriage or pregnancy loss, and pre‐eclampsia. Of the chosen studies, 18 suggested an association between periodontal disease and increased risk of adverse pregnancy outcome (ORs ranging from 1.10 to 20.0) and 7 found no evidence of an association (ORs ranging from 0.78 to 2.54). Three clinical trial studies suggest that oral prophylaxis and periodontal treatment can lead to a 57% reduction in preterm low birthweight (pooled RR 0.43; 95% CI 0.24–0.78) and a 50% reduction in preterm births (RR 0.5; 95% CI 0.20–1.30).

Author's conclusions  Periodontal disease may be associated with an increased risk of adverse pregnancy outcome. However, more methodologically rigorous studies are needed for confirmation.
Does a first trimester dating scan using crown rump length measurement reduce the rate of induction of labour for prolonged pregnancy? An uncompleted randomised controlled trial of 463 women
Authors: Harrington DJ , MacKenzie IZ , Thompson K , Fleminger M , Greenwood C
Published: January 2006

Objective  To evaluate the effect of a first trimester ultrasound dating scan on the rate of induction of labour for prolonged pregnancy.

Design  Randomised controlled trial to include 400 women in each arm of the trial.

Setting  Participating general practices and a district general teaching hospital.

Population  Women attending their general practitioner in the first trimester to confirm pregnancy, in whom a first trimester ultrasound scan was not indicated.

Methods  Women randomised to the study group (scan group) underwent an ultrasound dating scan between 8 and 12 weeks, measuring crown‐rump length. The estimated date of delivery (EDD) was changed if there was a discrepancy of more than 5 days from the gestation, calculated from the last menstrual period (LMP). For the remaining women (no‐scan group), gestation was determined using the LMP.

Main outcome measures  The rate of induction of labour for prolonged pregnancy.

Results  Due to circumstances beyond the researchers’ control, recruitment was abandoned when 463 women had been enrolled. The EDD was adjusted in 13 (5.7%) women in the scan group and in 2 (0.9%) in the no‐scan group. There was no difference in the rate of induction for prolonged pregnancy between the scan (19 [8.2%]) and the no‐scan (17 [7.4%]) groups (relative risk 1.10; 95% CI 0.59–2.07).

Conclusions  Acknowledging the reduced numbers recruited for study, it is concluded that there is no evidence that a first trimester ultrasound dating scan reduces the rate of induction of labour for prolonged pregnancy and may result in a more expensive healthcare strategy.
A prospective randomised controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum‐assisted vaginal delivery
Authors: Groom KM , Jones BA , Miller N , Paterson‐Brown S
Published: January 2006

Objective  To evaluate the performance and safety of the Kiwi Omnicup and compare it to conventional vacuum cups in routine clinical practice.

Design  A randomised controlled trial of the Kiwi Omnicup versus conventional vacuum cups.

Setting  Queen Charlotte's and Chelsea Hospital, a tertiary referral hospital in London from April 2001 to March 2004.

Population  Women requiring assisted vaginal delivery by ventouse.

Methods  Women were randomised to the Kiwi Omnicup (n = 206) or conventional vacuum cups (n = 198). Data regarding maternal demographics, labour, mode of delivery and maternal and neonatal outcome were collected.

Main outcome measures  Failure of delivery with instrument of first choice.

Results  The Kiwi Omnicup was less successful at delivery with instrument of first choice than the conventional ventouse, failure rate 30.1 versus 19.2% (RR 1.58; 95% CI 1.10–2.24). It was associated with a greater number of cup detachments (mean 0.68 compared with 0.28, with 44% compared with 18% having at least one detachment [P < 0.0001]). There was no difference in the incidence of severe maternal trauma, and there were no cases of serious neonatal injury.

Conclusions  The Kiwi Omnicup is less successful than conventional ventouse in achieving vaginal delivery, but its safety profile is comparable.
Does the angle of episiotomy affect the incidence of anal sphincter injury?*
Authors: Eogan M , Daly L , O'Connell PR , O'Herlihy C
Published: January 2006

Objective  Mediolateral episiotomy is associated with lower rates of significant perineal tears than midline episiotomy. However, the relationship between precise angle of episiotomy from the perineal midline and risk of third‐degree tear has not been established. This study quantifies this relationship.

Design  Case–control study.

Setting  National Maternity Hospital, Dublin, Ireland.

Sample  One hundred primiparous women who had undergone right mediolateral episiotomy 3 months previously.

Methods  Two groups of primiparous women were compared. Cases had sustained clinically apparent anal sphincter injury during delivery, while controls had not. The angle of episiotomy measured from the midline was marked on a superimposed sheet of transparent plastic film and measured using a protractor. Data were analysed using Student's t test, chi‐square test and logistic regression analysis.

Main outcome measures  Angle of mediolateral episiotomy from the perineal midline.

Results  Fifty‐four cases and 46 controls were assessed. Cases were more likely to have undergone assisted delivery and consequently to have been delivered by an obstetrician than by a midwife. The mean angle of episiotomy measured significantly smaller in cases (30°, 95% CI 28–32°) than in controls (38°, 95% CI 35–41°; P < 0.001). Analysis showed a 50% relative reduction in risk of sustaining third‐degree tear for every 6° away from the perineal midline that an episiotomy was cut.

Conclusions  These results show that a larger angle of episiotomy is associated with a lower risk of third‐degree tear and mediolateral episiotomy incisions should be made at as large an angle as possible to minimise the risk of sphincter disruption.
New postnatal urinary incontinence: obstetric and other risk factors in primiparae
Authors: Glazener CMA , Herbison GP , MacArthur C , Lancashire R , McGee MA , Grant AM , Wilson PD
Published: January 2006

Objective  To identify obstetric and other risk factors for urinary incontinence that occurs during pregnancy or after childbirth.

Design  Questionnaire survey of women.

Setting  Maternity units in Aberdeen (Scotland), Birmingham (England) and Dunedin (New Zealand).

Population  A total of 3405 primiparous women with singleton births delivered during 1 year.

Methods  Questionnaire responses and obstetric case note data were analysed using multivariate analysis to identify associations with urinary incontinence.

Main outcome measures  Urinary incontinence at 3 months after delivery first starting in pregnancy or after birth.

Results  The prevalence of urinary incontinence was 29%. New incontinence first beginning after delivery was associated with older maternal age (oldest versus youngest group, OR 2.02, 95% CI 1.35–3.02) and method of delivery (caesarean section versus spontaneous vaginal delivery, OR 0.28, 95% CI 0.19–0.41). There were no significant associations with forceps delivery (OR 1.18, 95% CI 0.92–1.51) or vacuum delivery (OR 1.16, 95% CI 0.83–1.63).

Incontinence first occurring during pregnancy and still present at 3 months was associated with higher maternal body mass index (BMI > 25, OR 1.68, 95% CI 1.16–2.43) and heavier babies (birthweight in top quartile, OR 1.56, 95% CI 1.12–2.19). In these women, caesarean section was associated with less incontinence (OR 0.39, 95% CI 0.27–0.58) but incontinence was not associated with age.

Conclusions  Women have less urinary incontinence after a first delivery by caesarean section whether or not that first starts during pregnancy. Older maternal age was associated with new postnatal incontinence, and higher BMI and heavier babies with incontinence first starting during pregnancy. The effect of further deliveries may modify these findings.
Altered placental syncytin and its receptor ASCT2 expression in placental development and pre‐eclampsia
Authors: Chen C‐P , Wang K‐G , Chen C‐Y , Yu C , Chuang H‐C , Chen H
Published: January 2006

Objective  To investigate the alterations of syncytin, a fusogenic membrane protein involved in syncytiotrophoblastic layer formation, and its receptor ASCT2 expression in placental development and pre‐eclampsia.

Design  Analyses of syncytin and ASCT2 expression in placentas from different stages of pregnancy and women with pre‐eclampsia and in cytotrophoblasts cultured in normoxic and hypoxic conditions.

Setting  Placental samples were collected from a tertiary medical centre.

Population  Sixteen women with pre‐eclampsia and 58 pregnant women presented as pregnancy (5–19 weeks of gestation) for elective termination, preterm birth, or normal term delivery.

Methods  The quantitative real‐time polymerase chain reaction was used to study the syncytin and ASCT2 expression during placental development in 35 placentas from women without pre‐eclampsia (ranged from 5 to 40 weeks of gestation) and the alterations of pre‐eclamptic placentas (n= 16) compared with gestational‐age‐matched controls (n= 16). Western blot analysis was performed to study the protein level of syncytin in pre‐eclamptic placentas and gestational‐age‐matched controls. The hypoxic effect on trophoblastic syncytin and ASCT2 expression was further studied in cytotrophoblasts cultured in 2% oxygen (n= 7).

Main outcome measures  Syncytin and ASCT2 messenger RNA (mRNA) in placental tissue and cytotrophoblasts.

Results  The level of syncytin mRNA expression increased significantly since the first trimester of pregnancy until 37 weeks of gestation, when the level of syncytin expression was reduced. The ASCT2 mRNA expression was decreased significantly since the second trimester and was relatively stable since then to 40 weeks of gestation. Furthermore, a significant reduction in syncytin mRNA expression was observed in pre‐eclamptic placentas and cytotrophoblasts cultured in hypoxia, but not a reduction in ASCT2 mRNA expression. Correlatively, the protein level of syncytin was decreased in pre‐eclamptic placentas.

Conclusions  A reduced placental expression of syncytin but not ASCT2 may contribute to altered cytotrophoblastic cell fusion processes and disturbed placental function in pre‐eclampsia. Correspondingly, hypoxia decreases syncytin but not ASCT2 gene expression in cultured cytotrophoblasts.
Conserving fertility in the management of gynaecological cancers
Authors: Farthing A
Published: January 2006

The quality of cancer treatment is judged by both morbidity and mortality. Patients benefit if morbidity is reduced without compromising mortality. This applies particularly for women who develop gynaecological malignancy during their childbearing years where curative treatment also renders them infertile. This study reviews the increasing role of fertility‐sparing surgery in such women. A literature search was undertaken using PubMed, entering the terms endometrial cancer, cervical cancer and ovarian cancer in conjunction with the terms fertility and fertility sparing. Each relevant identified paper was reviewed, references checked and results collated to provide an evidence‐based summary of fertility‐sparing treatments for gynaecological malignancy. Fertility‐sparing surgery is appropriate in many circumstances, and all doctors who advise young women with gynaecological malignancy should be aware of these possibilities. However, data are relatively sparse in many situations, and careful counselling and balanced guidance are essential if patients are to understand the full implications of their choices.
Occult anal sphincter injuries—myth or reality?
Authors: Andrews Vasanth , Sultan Abdul H , Thakar Ranee , Jones Peter W
Published: January 2006

Objectives  To establish the true prevalence of clinically recognisable and occult obstetric anal sphincter injuries (OASIS).

Design  Prospective interventional study.

Setting  Busy district general hospital.

Sample  Two hundred and fifty‐four women having their first vaginal delivery over a 12‐month period were invited. Two hundred and forty‐one (95%) participated and 208 (86%) attended follow up.

Methods  Women had a clinical examination at delivery by the accoucheur and repeated by an experienced research fellow immediately after delivery. All identified OASIS were verified and repaired by the duty specialist registrar or consultant. Endoanal ultrasound was performed immediately postpartum prior to suturing and repeated seven weeks later.

Main outcome measures  Prevalence of recognised and occult anal sphincter injuries.

Results  Fifty‐nine (24.5%) women sustained OASIS. The prevalence of OASIS increased significantly from 11% to 24.5% when women were re‐examined. Of these, 30 occurred in deliveries by midwives who missed 26 (87%) and 29 following deliveries by doctors who missed 8 (28%) injuries. All clinically apparent OASIS were also identified on endoanal ultrasound. In addition, three (1.2%) women had an occult anal sphincter injury. Two of these occult sphincter injuries were isolated to the internal anal sphincter (IAS) and would not usually be clinically detectable.

Conclusions  OASIS occur more frequently than previously reported. Many remain undiagnosed and are subsequently classified as occult when identified on anal endosonography. Genuine occult injuries are rare. Training in perineal anatomy and recognition of OASIS needs to be enhanced in order to increase detection of OASIS and minimise the risk of consequent anal incontinence.
Does training in obstetric emergencies improve neonatal outcome?
Authors: Draycott Tim , Sibanda Thabani , Owen Louise , Akande Valentine , Winter Cathy , Reading Sandra , Whitelaw Andrew
Published: January 2006

Objectives  To determine whether the introduction of Obstetrics Emergency Training in line with the recommendations of the Clinical Negligence Scheme for Trusts (CNST) was associated with a reduction in perinatal asphyxia and neonatal hypoxic–ischaemic encephalopathy (HIE).

Design  A retrospective cohort observational study.

Setting  A tertiary referral maternity unit in a teaching hospital.

Population  Term, cephalic presenting, singleton infants born at Southmead Hospital between 1998 and 2003 were identified; those born by elective Caesarean sections were excluded.

Method  Five‐minute Apgar scores were reviewed. Infants that developed HIE were prospectively identified throughout this period. The study compared the period ‘pre‐training’ (1998–1999), with the period ‘post‐training’ (2001–2003).

Main outcome measures  Five‐minute Apgar scores and HIE.

Results  Infants (19,460) were included. Infants born with 5‐minute Apgar scores of ≤6 decreased from 86.6 to 44.6 per 10,000 births (P < 0.001) and those with HIE decreased from 27.3 to 13.6 per 10,000 births (P= 0.032) following the introduction of the training courses in 2000. Antepartum and intrapartum stillbirth at term rates remained unchanged, at about 15 and 4 per 10,000 births, respectively.

Conclusion  The introduction of obstetric emergencies training courses was associated with a significant reduction in low 5‐minute Apgar scores and HIE. This improvement has been sustained as the training has continued. This is the first time an educational intervention has been shown to be associated with a clinically important, and sustained, improvement in perinatal outcome.
Non‐invasive first trimester determination of fetal gender: a new approach for prenatal diagnosis of haemophilia
Authors: Chi C , Hyett JA , Finning KM , Lee CA , Kadir RA
Published: January 2006

Ten carriers of haemophilia referred for prenatal diagnosis were offered first trimester non‐invasive fetal gender determination by ultrasound and analysis of free fetal DNA (ffDNA) in maternal plasma in an attempt to reduce the need for an invasive diagnostic procedure in female pregnancies. Although repeat testing was required in three cases, fetal gender was determined correctly in all cases (four females, six males) at a median gestation of 12+3(11+2to 14+1) using both methods. In all cases of a female fetus, the mothers opted not to have invasive testing. Both methods provide a reliable option of avoiding invasive testing in female pregnancies.
The prevalence of major abnormalities of the levator ani in urogynaecological patients
Authors: Dietz HP , Steensma AB
Published: January 2006

Objectives  While morphological abnormalities of the pubovisceral muscle have been described on magnetic resonance imaging (MRI), their relevance remains unclear. This study was designed to define prevalence and clinical significance of such abnormalities in urogynaecological patients.

Design  Prospective observational study.

Setting  Tertiary urogynaecological clinic.

Population  Three hundred and thirty‐eight consecutive women referred for urodynamic assessment.

Methods  Participants underwent a clinical assessment, multichannel urodynamics and imaging with 3D translabial ultrasound. Blinded offline analysis was performed with the software 4D View (GE Kretztechnik, Zipf, Austria).

Main outcome measures  Major morphological abnormalities of the pubovisceral muscle.

Results  Defects of the pubovisceral muscle were found in 15.4% of parous women. They were exclusively anteromedial (uni‐ or bilateral), only occurred among women who had delivered vaginally and were associated with anterior and central compartment prolapse (all P < 0.001). There was no association with symptoms of bladder dysfunction or urodynamic findings.

Conclusions  Major morphological abnormalities of the pubovisceral muscle are common in parous urogynaecological patients. They are associated with prolapse of the anterior and central compartment, but not with symptoms of bladder dysfunction or urodynamic findings.
How Did Welfare Reform Affect the Health Insurance Coverage of Women and Children?
Authors: Cawley John , Schroeder Mathis , Simon Kosali I.
Published: January 2006

Objective. To measure the change in U.S. women and children's health insurance coverage as a result of welfare reform (i.e. the creation of Temporary Assistance for Needy Families or TANF) in 1996.

Data Source. 1992–1999 longitudinal data from the Survey of Income and Program Participation (SIPP) merged with data on the timing of state implementation of welfare reform after 1996. Two key advantages of the SIPP data are that they permit matching type of insurance coverage to the welfare policy environment in each state in each month, and permit controlling for individual‐level fixed effects.

Study Design. We measure how much insurance coverage changed after welfare reform using a difference in differences method that eliminates the influence of time‐invariant unobserved individual heterogeneity and of statewide trends in insurance coverage. Models also control for individual, state, and year fixed effects, individual‐level characteristics such as education, age, and number of children, plus state‐level variables such as real per capita income, real minimum wage, and Medicaid eligibility.

Data Collection/Extraction Methods. We limit our analysis to the SIPP data specific to the month just completed prior to the interview; as a result, we have up to twelve observations for each individual in the SIPP. This paper uses pooled data from the 1992–1996 panels of the SIPP covering the period 1992–1999. Publicly available state identifiers permit the merger of state policies and macroeconomic variables with the SIPP.

Principal Findings. TANF implementation is associated with an 8.1 percent increase in the probability that a welfare‐eligible woman was uninsured. Welfare reform had less of an impact on the health insurance coverage of children. For example, TANF implementation was associated with a 3.0 percent increase in the probability that a welfare‐eligible child lacked health insurance.

Conclusions. An unintended consequence of welfare reform was to adversely impact the health insurance coverage of economically vulnerable women and children, and that this impact was several times larger than the previous literature implies.
Religious Involvement and the Use of Mental Health Care
Authors: Harris Katherine M. , Edlund Mark J. , Larson Sharon L.
Published: January 2006

Objectives. To examine the association between religious involvement and mental health care use by adults age 18 or older with mental health problems.

Methods. We used data from the 2001–2003 National Surveys on Drug Use and Health. We defined two subgroups with moderate (n=49,902) and serious mental or emotional distress (n=14,548). For each subgroup, we estimated a series of bivariate probit models of past year use of outpatient care and prescription medications using indicators of the frequency of religious service attendance and two measures of the strength and influence of religious beliefs as independent variables. Covariates included common Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, disorders symptoms, substance use and related disorders, self‐rated health status, and sociodemographic characteristics.

Results. Among those with moderate distress, we found some evidence of a positive relationship between religious service attendance and outpatient mental health care use and of a negative relationship between the importance of religious beliefs and outpatient use. Among those with serious distress, use of outpatient care and medication was more strongly associated with service attendance and with the importance of religious beliefs. By contrast, we found a negative association between outpatient use and the influence of religious beliefs on decisions.

Conclusion. The positive relationship between religious service participation and service use for those with serious distress suggests that policy initiatives aimed at increasing the timely and appropriate use of mental health care may be able to build upon structures and referral processes that currently exist in many religious organizations.
Operational Failures and Interruptions in Hospital Nursing
Authors: Tucker Anita L. , Spear Steven J.
Published: January 2006

Objective. To describe the work environment of hospital nurses with particular focus on the performance of work systems supplying information, materials, and equipment for patient care.

Data Sources. Primary observation, semistructured interviews, and surveys of hospital nurses.

Study Design. We sampled a cross‐sectional group of six U.S. hospitals to examine the frequency of work system failures and their impact on nurse productivity.

Data Collection. We collected minute‐by‐minute data on the activities of 11 nurses. In addition, we conducted interviews with six of these nurses using questions related to obstacles to care. Finally, we created and administered two surveys in 48 nursing units, one for nurses and one for managers, asking about the frequency of specific work system failures.

Principal Findings. Nurses we observed experienced an average of 8.4 work system failures per 8‐hour shift. The five most frequent types of failures, accounting for 6.4 of these obstacles, involved medications, orders, supplies, staffing, and equipment. Survey questions asking nurses how frequently they experienced these five categories of obstacles yielded similar frequencies. For an average 8‐hour shift, the average task time was only 3.1 minutes, and in spite of this, nurses were interrupted mid‐task an average of eight times per shift.

Conclusions. Our findings suggest that nurse effectiveness can be increased by creating improvement processes triggered by the occurrence of work system failures, with the goal of reducing future occurrences. Second, given that nursing work is fragmented and unpredictable, designing processes that are robust to interruption can help prevent errors.
The Devil's Altar? Crime and the Early Modern Public House
Authors: Kümin Beat
Published: January 2006

Was the early modern public house really such a dangerous place, as Puritan preachers (and many historians) suggested? This article discusses offences by publicans and patrons. It argues that the evidence for crime needs to be carefully contextualised and that taverns could stabilise as well as threaten the social order.
‘Healthy Types of Young Danes’: Australia's Unwilling Post‐War Migrants
Authors: Kristensen Jeppe
Published: January 2006

Following the Second World War the Chifley government initiated an ambitious new immigration programme, which would dramatically alter the make‐up of Australian society. This article focuses on the initial Australian preference for white‐skinned migrants from Scandinavia, and the response of one of those countries – Denmark – to the Australian recruiting drive. It examines the official Danish resistance to Australian migration initiatives, and the way in which Australia was portrayed in Denmark. It is argued that the migrant issue went further than economic opportunity, and can be understood in terms of a discursive clash between dominant national myths in the respective countries – with Australia as a natural haven for energetic, opportunity‐seeking Europeans, and Denmark as a humane, sophisticated welfare state that took care of its citizens from cradle to grave. Understanding how alternative, non‐British sources of white immigration dried up in the post‐war era is a hitherto neglected context for understanding Australia's gradual retreat from the ‘white Australia’ immigration policy.
The Question of Economic Decline in Seventeenth‐Century Italy: Myth or Reality?
Authors: D’Amico Stefano
Published: January 2006

Was the Italian economic crisis of the seventeenth century an irreversible decline or a readjustment of the socio‐economic structures? Did the prosperous Italian cities lose forever their economic role or were they able to adapt to the changing demands of the international markets? This article examines the main phases of the historiographical debate on these issues from its beginning in the 1950s to the most recent developments.
Particle Size Comparison of Soft‐Chemically Prepared Transition Metal (Co, Ni, Cu, Zn) Aluminate Spinels
Authors: Dhak Debasis , Pramanik Panchanan
Published: January 2006

Nanocrystalline MAl2O4 (M=Co, Ni, Cu, Zn) spinel powders are synthesized by pyrolysis of complex compounds of aluminum and transition metal (cobalt, nickel, copper, and zinc) with triethanolamine (TEA). The precursor materials are formed on complete dehydration of the soluble complexes of aluminum–TEA and transition metal–TEA (Co, Ni, Cu, Zn), maintaining the resulting pH of each of the solutions at 4–5. The precursors are heat treated at different temperatures to provide phase formations. Single‐phase MAl2O4 spinel powders were obtained after heat treatment of the precursor material at 600°C, but for CuAl2O4, the precursor passed through an intermediate‐phase CuO at a lower treatment temperature. The precursor and the heat‐treated powders were characterized by X‐ray diffraction (XRD), Fourier‐transform infrared spectrometry, thermal gravimetric and differential thermal analysis, and transmission electron microscopy (TEM); the surface area was measured by a Brunauer–Emmet–Teller (BET) adsorption isotherm. The average particle sizes that were obtained from XRD, TEM, and BET adsorption isotherm were compared.
Comparison Between Micrometer‐ and Nano‐Scale Glass Composites for Sealing Solid Oxide Fuel Cells
Authors: Brochu M. , Gauntt B. D. , Shah R. , Loehman R. E.
Published: January 2006

The present study compares the feasibility of controlling the properties of a glass composite seal by adding nano‐ or micron‐scale yttria‐stabilized zirconia (YSZ) powders to a borate glass used for sealing electrolyte‐supported solid oxide fuel cells (SOFCs). The crystallization of the glass composites was found to be independent of the volume fraction of added YSZ, for both sizes of the additive. The variation of the flow properties of both composite seals was measured using a wettability test, and an increase of the contact angle was observed when the volume fraction of additives was increased. The major factor found to decrease spreading of the glass composite was the additive particle size, where shape retention was observed for the nanometer (nm)‐YSZ composites while spreading of the micrometer (μm)‐YSZ composites was observed under the same testing conditions. Examination of the microstructure showed that initially the Ba‐containing glass reacted with YSZ to form a BaZrO3 compound. Long‐time exposure at 800°C caused a large reduction in the coefficient of thermal expansion (CTE), which can be explained by increased formation of BaZrO3 and further change in glass composition. This change in CTE occurs rapidly for the nm‐YSZ composites, which is not observed for the μm‐YSZ composites. However, the adverse reactions occurring between the additives and the glass matrix were found to reduce the CTE of the glass composites to a value lower than the recommended limit for a system used for sealing SOFCs.
Processing and Structure Relationships in Electrospinning of Ceramic Fiber Systems
Authors: Sigmund Wolfgang , Yuh Junhan , Park Hyun , Maneeratana Vasana , Pyrgiotakis Georgios , Daga Amit , Taylor Joshua , Nino Juan C.
Published: January 2006

During the last years, several groups across the world have concentrated on the adaptation and further development of electrospinning (e‐spinning) to enable ceramic fiber synthesis. Thus far, more than 20 ceramic systems have been synthesized as micro‐ and nanofibers. These fibers can be amorphous, polycrystalline, dense, porous, or hollow. This article reviews the experimental and theoretical basis of ceramic e‐spinning. Furthermore, it introduces an expanded electro hydrodynamic (EHD) theory that allows the prediction of fired fiber diameter for lanthanum cuprate fibers. It is hypothesized that this expanded EHD theory is applicable to most ceramic e‐spinning systems. Furthermore, electroceramic nanofibers produced via e‐spinning are presented in detail along with an overview of electrospun ceramic fibers.
Mechanochemical‐Activation‐Assisted Combustion Synthesis of α‐Si3N4
Authors: Jin Hai‐Bo , Yang Yun , Chen Yi‐Xiang , Lin Zhi‐Ming , Li Jiang‐Tao
Published: January 2006

Combustion synthesis (CS) of α‐silicon nitride (Si3N4) powders was accomplished at a nitrogen pressure lower than 3 MPa. The combination of mechanical activation and chemical stimulation was effective in enhancing the reactivity of Si powder reactants, which was responsible for the reduction of the minimum nitrogen pressure normally required for the CS of Si3N4. This breakthrough indicates that nitriding combustion of silicon in pressurized nitrogen could be promoted by activating the solid reactants instead of by increasing the nitrogen pressure. The phase content of α‐Si3N4 in the as‐synthesized product is over 90 wt%. Scanning electronic microscopy observation showed that the combustion‐synthesized Si3N4 powders are submicron‐sized particles with spherical morphologies.
Tubular La0.7Ca0.3Fe0.85Co0.15O3−δ Perovskite Membranes, Part II: Performance and Stability
Authors: Trunec Martin , Cihlar Jaroslav , Diethelm Stefan , Van Herle Jan
Published: January 2006

Oxygen permeability through the tubular La0.7Ca0.3Fe0.85Co0.15O3−δ perovskite membrane prepared by thermoplastic extrusion was measured in the temperature range from 800° to 1040°C in an air/argon gradient, and compared with the oxygen permeability of planar membranes prepared by injection molding and cold isostatic pressing. Oxygen flux through the perovskite membranes was controlled by bulk diffusion of oxygen and was not limited by surface exchange reactions. The oxygen flux through perovskite membranes normalized to 1 mm wall thickness at 900°C was 0.064 μmol (cm2 s)–1. The activation energy of oxygen diffusion was 128 kJ mol−1. The tubular membrane was tested in a reactor for partial oxidation of methane for more than 1900 h. The oxygen flux decreased gradually during the test from 1.5 to 1 μmol (cm2 s)–1. The methane conversion could be adjusted to 83%–88%, with the CO selectivity in the same range. After the test, a degradation of the perovskite structure of the membrane was observed. A possible mechanism for the phase degradation and segregation was proposed.
Origin of the Potential Drop Over the Deposit During Electrophoretic Deposition
Authors: Anné G. , Neirinck B. , Vanmeensel K. , Van der Biest O. , Vleugels J.
Published: January 2006

A model is developed to explain the origin of the potential drop over the deposit during electrophoretic deposition (EPD). The magnitude of the potential drop over the deposit is explained in terms of the ion transport through the deposit, as controlled by the pore potential that is related to the thickness of the electrostatic double layer relative to the pore radius and the magnitude of the surface potential of the powder particles. This model is verified for EPD of Al2O3 powder in ethanol‐based suspensions with HNO3 as a function of the operational pH.
Correlation Between Microstructure and Creep Behavior in Liquid‐Phase‐Sintered α‐Silicon Carbide
Authors: Castillo‐Rodríguez M. , Muñoz A. , Domínguez‐Rodríguez A.
Published: January 2006

The influence of increasing the sintering time from 1 to 7 h on the microstructure evolution and the mechanical properties at high temperature was studied in α‐silicon carbide (α‐SiC) sintered in argon atmosphere with Y2O3–Al2O3 (10% weight) as liquid phase (LPS‐α‐SiC). The density decreased from 98.8% to 94.9% of the theoretical value, the grain size increased from 0.64 to 1.61 μm, and some of the grains became elongated. The compression tests were performed in argon atmosphere, between 1450°C and 1625°C and stresses between 25 and 450 MPa, with the strain rate being between 4.2 × 10−8 and 1.5 × 10−6 s−1. The stress exponent n and the activation energy Q were determined, finding values of n between 2.4±0.1 and 4.5±0.2 and Q=680±35 kJ/mol for samples sintered for 1 h, and n between 1.2±0.1 and 2.4±0.1 and Q=710±90 kJ/mol for samples sintered for 7 h. The correlation between these results and the microstructure indicates that grain‐boundary sliding and the glide and climb of dislocations, both accommodated by bulk diffusion, may be two independent deformation mechanisms operating. At the temperatures of the tests, the existence of solid‐state reactions between SiC and the sintering additives is responsible of the microstructural changes observed. These effects are not a consequence of the process of deformation, but rather they are because of the thermal treatment of the material during the creep.
Effect of ZnO and CuO on the Sintering Temperature and Piezoelectric Properties of a Hard Piezoelectric Ceramic
Authors: Ahn Cheol‐Woo , Song Hyun‐Cheol , Nahm Sahn , Priya Shashank , Park Seung‐Ho , Uchino Kenji , Lee Hyeung‐Gyu , Lee Hwack‐Joo
Published: January 2006

Hard piezoelectrics with high dielectric and piezoelectric constants are used for high‐power applications. However, the sintering temperature of these ceramics is high, around 1200°C, restricting the usage of cheap base metal electrodes in fabrication of multi‐layer components. This study investigates the effect of CuO and ZnO on the sintering temperature of a hard piezoelectric, APC 841, which is a MnO2‐ and Nb2O5‐modified PZT. The addition of CuO decreased the sintering temperature through the formation of a liquid phase. However, the piezoelectric properties of the CuO‐added ceramics sintered at ≤950°C were lower than the desired values. The addition of ZnO resulted in a significant improvement in the piezoelectric properties. This enhancement was attributed to the formation of a homogeneous microstructure with large grains. The APC 841+0.2 wt% CuO+1.1 wt% ZnO ceramics sintered at 950°C showed excellent piezoelectric and dielectric properties with values of kp=0.532, Qm=750, d33=351 pC/N, ɛ33/ɛo=1337, and Tc=280°C.
Microstructural and Microchemical Characterization of Roman Period Terra Sigillate Slips from Archeological Sites in Southern France
Authors: Sciau Philippe , Relaix Sabrina , Roucau Christian , Kihn Yolande , Chabanne Delhia
Published: January 2006

Terra Sigillata is a fine ware produced during the Roman period. Its great success was because of its remarkable gloss (or slip), which provides a bright deep red color. Transmission electron microscopy and X‐ray powder diffraction techniques were used to characterize the microstructure and microcomposition of Roman period Terra Sigillata slip from two sites in southern France. Investigations on eight samples are presented. The slip coatings have similar structures and compositions, consisting of sub‐micrometric hematite (≤μm) and nanometric corundum (few tens nm) crystals in a glass matrix with inclusions of spinel and quartz crystals of varying size depending on the extent of preparation by eleutriation. The firing temperature, determined in previous studies, was in the range of 1020°–1080°C. The matrix does not contain iron or other metallic ions. Hematite and corundum crystals are homogeneously dispersed in the matrix and, together, confer the specific red‐orange color to the sigillata.
Synthesis and Characterization of Nanoscaled Cerium (IV) Oxide via a Solid‐State Mechanochemical Method
Authors: Lu Jun , Fang Zhigang Zak
Published: January 2006

Solid‐state reactions have the potential for direct preparation of ceramic powders and offer a low‐temperature and low‐cost alternative to conventional techniques for production of oxide powders. This paper describes a simple and effective mechanochemical method based on solid‐state reactions during ball milling for synthesis of nanoscaled ceria (CeO2) particles. By using an organic base instead of an inorganic base, metal‐ion‐free nanoscaled CeO2can also be made. The effects of annealing temperature on particle sizes and lattice strain are investigated. The results show that the average particle sizes of the particles increases and the average crystal lattice distortion decreases with the annealing temperature. Transmission electron microscopy examinations demonstrate that the CeO2particles synthesised by this method are near‐spherical shaped.
Preparation of a Highly Conductive Al2O3/TiN Interlayer Nanocomposite through Selective Matrix Grain Growth
Authors: Jin Xihai , Gao Lian
Published: January 2006

An electroconductive TiN/Al2O3 nanocomposite was prepared by a selective matrix grain growth method, using a powder mixture of submicrosized α‐Al2O3, nanosized γ‐Al2O3, and TiN nanoparticles synthesized through an in situ nitridation process. During sintering, a self‐concentration of TiN nanoparticles at the matrix grain boundary occurred, as a result of the selective growth of large α‐Al2O3 matrix grains. Under suitable sintering conditions, a typical interlayer nanostructure with a continuous nanosized TiN interlayer was formed along the Al2O3 matrix grain boundary, and the electroconducting behavior of the material was significantly improved. Twelve volume percent TiN/Al2O3 nanocomposite with such an interlayer nanostructure showed an unprecedentedly low resistivity of 8 × 10−3Ω·cm, which was more than two orders lower than the TiN/Al2O3 nanocomposite without such an interlayer nanostructure.
Personality traits as correlates of suicidal ideation, suicide attempts, and suicide completions: a systematic review
Authors: Brezo J. , Paris J. , Turecki G.
Published: January 2006

Objective:  Involvement of personality traits in susceptibility to suicidality has been the subject of research since the 1950s. Because of the diversity of conceptual and methodological approaches, the extent of their independent contribution has been difficult to establish. Here, we review conceptual background and empirical evidence investigating roles of traits in suicidal behaviors.

Method:  We selected original studies published in English in MEDLINE and PsycINFO databases, focusing on suicidal ideation, suicide attempts, or suicide completions, and using standardized personality measures.

Results:  Most studies focused on investigating risk for suicide attempts. Hopelessness, neuroticism, and extroversion hold the most promise in relation to risk screening across all three suicidal behaviors. More research is needed regarding aggression, impulsivity, anger, irritability, hostility, and anxiety.

Conclusion:  Selected personality traits may be useful markers of suicide risk. Future research needs to establish their contributions in relation to environmental and genetic variation in different gender, age, and ethnocultural groups.
The ductus venosus and intrahepatic venous system in Callithrix jacchus jacchus and Macaca fascicularis fetuses
Authors: Tchirikov Michael , Schlabritz‐Loutsevitch Natalia E. , Hubbard Gene B. , Tardif Suzette , Schröder Hobe J. , Nathanielsz Peter W.
Published: January 2006

Background The ductus venosus (DV) and the intrahepatic branches of the portal vein are arranged as parallel vessels. Blood shunting through the DV ensures fetal survival during periods of stress. The availability of a suitable animal model with similar structure and function to the human fetus would greatly improve the understanding of DV function. The anatomical and histological structure of the DV has not been thoroughly investigated in non‐human primate species.

Methods Morphological investigations were performed on eight marmoset (Callithrix jacchus jacchus) at 112.5 ± 5.5 days gestational age (mean ± SEM) and four near‐term (165 days) cynomolgus (Macaca fascicularis) fetuses.

Results The DV drains into the collectus venosus. An asymmetrical muscular lip forms a contractile element of the isthmic portion of the DV. A spherical ‘dividing’ eminence was found on the dorsal wall of the venous collector just above the outlet of the DV in marmoset fetuses.

Conclusions Our findings regarding the structure of the DV in cynomolgus and marmoset fetuses were generally in agreement with previous descriptions of the morpho‐histological structure of the DV in human fetuses.
Imaginary Pilgrimages: Felicia Hemans, Dead Poets, and Romantic Historiography
Authors: Westover Paul
Published: January 2006

Critics of Felicia Hemans often discuss her historiography, observing that her poetry injects the domestic, the feminine, and the sentimental into “official” history.1This essay suggests that Hemans's historiography was neither entirely novel nor purely oppositional, but rather a manifestation of a widespread Romantic‐era conviction that history was not merely something to read about, but also an experience to be felt and a place to be visited.

 In their engagements with the dead and their concomitant interest in imaginative historical transport, many of Hemans's poems highlight tensions between ideals of affective proximity and critical distance that troubled Romantic‐era historians and continue to vex historicist critics. Thus, this essay takes Hemans as a case study in the methodological difficulties of memorialization, especially in the New Historicist project.
Face to Face with Johann Caspar Lavater
Authors: Erle Sibylle
Published: January 2006

At the end of the eighteenth century, Europe‐wide debates on the nature of man and the practice of interpreting visual artefacts centred on physiognomy, and specifically on one extraordinary, luxuriously illustrated work which claimed to map out how character could precisely be read in the human face: Johann Caspar Lavater's Essays on Physiognomy.
Constructing Caribbean Literary History
Authors: Krise Thomas W.
Published: January 2006

Responding to reviews of his Caribbeana: An Anthology of English Literature of the West Indies, 1657–1777 by historian Richard Drayton and Nobel laureate Derek Walcott, Thomas W. Krise responds to questions about the writing of the literary history of the early Caribbean, including: What constitutes Caribbean literature? How does early Caribbean literature compare to early North American literature? How should critics deal with the lack of records from oral cultures? And, should early Caribbean literature be taught, and, if so, how?
Mapping the Victorian Sensation Novel: Some Recent and Future Trends
Authors: Maunder Andrew
Published: January 2006

The past twenty years has seen a growing interest in the phenomenon of the sensation novel which is no longer regarded as indisputably unimportant or devoid of interest in studies of Victorian literature. Arguing that research into the genre has reached a crossroads, this article offers an overview of the sensation genre and some of the issues which have interested critics to date, in particular the association with women writers and readers. It suggests some of the different ways in which future work might go and draws attention to the sensation novel's diversity in terms of genre, form and subject matter, suggesting that the genre is not as easy to label as it first seems.
A ‘Perfect Circle’? Alchemy in the Poetry of Hester Pulter
Authors: Archer Jayne
Published: January 2006

Relatively little is known about women's knowledge of natural philosophy in early modern England. Manuscript and printed receipt books show that women, by virtue of their work in the household, were experts in the alchemical processes of sublimation, fermentation, calcination and distillation. The poetry of Hester Pulter (1596–1678) is remarkable for a sophisticated use of terms, images and conceits drawn from alchemy. As such, it provides important evidence of one woman's imaginative and intellectual engagements with the experimental, esoteric and emblematic traditions in alchemy. Paying particular attention to a cycle of poems entitled ‘The Circle’, I show how Pulter tirelessly worked and reworked alchemical concepts and images, and, just like an alchemist, transformed them into something new.