bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute obstetric emergency drill in England and Wales: a survey of practice
Authors: Anderson Elizabeth R. , Black Rebecca , Brocklehurst Peter
Published: February 2005

Multidisciplinary training for obstetric emergencies is an issue of current interest and debate in the UK. This paper presents a survey of current practice in obstetric emergency drill training in England and Wales. A wide range of training methods and opinions about these methods are demonstrated in this survey. There is much interest in improving the management of obstetric emergencies and this is to be encouraged. However, reliable methods to assess and thereby optimise methods are urgently required in order that women and their babies can realise the maximum benefit from these complex interventions.
Lung and brain damage in preterm newborns, and their association with gestational age, prematurity subgroup, infection/inflammation and long term outcome
Authors: Dammann Olaf , Leviton Alan , Gappa Monika , Dammann Christiane E.L.
Published: February 2005

Compared with those born at term, preterm newborns are at an increased risk of short term disorders of the lung (bronchopulmonary dysplasia; BPD) and the brain (white matter damage; WMD), and of long term developmental and pulmonary dysfunctions. Although all of these adverse outcomes are associated with low gestational age, brain, but not lung, damage appears to be associated with the prematurity subgroup [spontaneous preterm labour and/or preterm prelabour rupture of membranes (PPROM) vs pregnancy‐induced hypertension (PIH)]. Part of the association between brain damage and prematurity subgroup might be due to a differential exposure of members of these subgroups to perinatal infection/inflammation. There is a lack of studies evaluating the association of antenatal and perinatal risk factors with late childhood pulmonary dysfunction among those born during the second trimester. In this paper we discuss the complexities that paediatricians, perinatologists and perinatal epidemiologists face as they try to understand the contributions of factors associated with preterm birth to neonatal and childhood disorders.
Role of cytokines in preterm labour and brain injury
Authors: Hagberg Henrik , Mallard Carina , Jacobsson Bo
Published: February 2005

Intrauterine infection induces an intra‐amniotic inflammatory response involving the activation of a number of cytokines and chemokines which, in turn, may trigger preterm contractions, cervical ripening and rupture of the membranes. Infection and cytokine‐mediated inflammation appear to play a prominent role in preterm birth at early gestations (<30 weeks). The role of infection/inflammation in preterm birth in Europe has been incompletely characterised. The rate of preterm birth in Sweden is lower, and the rate of chorioamnionitis, bacterial vaginosis (BV), neonatal sepsis, and urinary tract infections during pregnancy is lower compared with the USA. In a Swedish population of women with preterm labour or preterm premature rupture of the membranes (PPROM) <34 weeks of gestation, microorganisms were detected in the amniotic fluid in 25% of women with PPROM and in 16% of those in preterm labour. Nearly half of these women had intra‐amniotic inflammation defined as elevated interleukin‐6 (IL‐6) and IL‐8, and there was a high degree of correlation between cytokine levels and preterm birth or the presence of microbial colonisation. These data do not support the hypothesis that infection‐related preterm birth is less frequent in northern Europe than elsewhere. The intra‐amniotic inflammatory response has also been associated with white matter injury and cerebral palsy. We find that in experimental models, induction of a systemic inflammatory response using lipopolysaccharide activates toll‐like receptors (TLRs), which produce either white matter lesions or increase brain susceptibility to secondary insults. Recently, IL‐18 in umbilical blood was shown to correlate with brain injury in preterm infants and IL‐18 deficiency in mice decreases CNS vulnerability.
Current understanding of genetic factors in preterm birth
Authors: Varner Michael W. , Esplin M. Sean
Published: February 2005

Several lines of evidence support a genetic predisposition to spontaneous preterm labour and preterm birth. Firstly, a leading risk factor for spontaneous preterm labour and preterm birth is a personal or family history. If a woman previously delivered preterm, her subsequent babies are also more likely to be born preterm. Women who experienced an early preterm birth (<32 completed weeks) in their first pregnancy have the highest rate of recurrent preterm birth in subsequent pregnancies. Spontaneous preterm labour and preterm birth in subsequent pregnancies tend to recur at equivalent gestational ages. If a woman herself was born preterm, she is also at an increased risk of spontaneous preterm labour and preterm birth, with the risks being highest for those women who themselves were born most preterm. This predisposition does not apply to men who were born preterm. Racial predispositions to preterm birth have also been observed. Black women suffer twice the rate of preterm birth compared with Caucasians, even when confounding social and economic variables are controlled. It is well established that upper genital tract infection and/or inflammation is seen in association with spontaneous preterm labour and preterm birth. Previous investigations have focussed primarily on an infectious aetiology for this finding. However, an alternative hypothesis has emerged, which suggests that this finding may represent an abnormal inflammatory response. The frequent association of spontaneous preterm labour and preterm birth with histological infection/inflammation and elevated body fluid concentrations of inflammatory cytokines has focussed investigations on single gene polymorphisms of these cytokines in both mother and fetus. The polymorphisms tumour necrosis factor‐α‐308 (TNF‐α‐308), interleukin‐1β (IL‐1β) + 3953/3954 and IL‐6–174 have been most consistently associated with spontaneous preterm labour and preterm birth. Toll‐like receptors (TLRs) are important components of the innate immune systems, which have also been linked to spontaneous preterm labour and preterm birth. Both maternal and fetal polymorphisms of the TLR‐4 gene have been associated with spontaneous preterm labour and preterm birth in certain populations, but in others no apparent link has been observed. These findings confirm a clear genetic predisposition to spontaneous preterm labour and preterm birth and raise hopes that patient‐specific therapies may be developed in the future.
Secondary predictors of preterm labour
Authors: Leitich Harald
Published: February 2005

In addition to primary predictors of preterm birth which are used to estimate the baseline risk of preterm birth, secondary predictors (based on examinations done during the current pregnancy) allow a more accurate assessment of the risk of preterm birth in individual women. Screening for early signs of spontaneous preterm labour has always been an important topic in obstetric care. During the last two decades, the detection of fetal fibronectin (FFN) from cervicovaginal secretions and cervical shortening diagnosed by transvaginal ultrasonography have emerged as the major secondary predictors of preterm birth. Both markers have been extensively studied and consistently shown to be strong short term predictors of preterm birth across a wide range of gestational ages. Other secondary predictors that confirm the role of intrauterine infection in the pathogenesis of preterm birth are bacterial vaginosis (BV) and elevated levels of interleukin (IL)‐6, IL‐8, ferritin and granulocyte colony‐stimulating factor. Apart from BV, inflammatory markers are still not routinely used. The sensitivity of single markers in predicting preterm birth is only moderate and serial examinations of markers, combinations of different markers and multiple marker tests have been studied, with limited results. Studies of interventions in order to prevent preterm birth have also yielded mixed benefits, as a consequence of which the use of these markers to screen low risk pregnancies is generally not recommended. Currently, secondary predictors of preterm birth are used mainly to design new intervention studies tailored to specific high risk populations and to avoid unnecessary interventions in the management of high risk women.
Strategies for prevention—cervical cerclage
Authors: Althuisius Sietske M. , van Geijn Herman P.
Published: February 2005

Transvaginal cervical cerclage was introduced as a treatment for cervical incompetence in 1951. Over the years, our understanding of this clinical entity has changed tremendously, which has implications for obstetric management. This review focuses on the obstetric management of women considered to be at high risk of preterm delivery due to cervical incompetence at different stages of pregnancy.
The changing role of progesterone in preterm labour
Authors: Di Renzo G.C. , Rosati A. , Mattei A. , Gojnic M. , Gerli S.
Published: February 2005

Progesterone is an essential hormone in the process of reproduction. It is involved in the menstrual cycle, implantation and is essential for pregnancy maintenance. Although the pharmacokinetics and pharmacodynamics of progesterone have been well studied, and since 1935 it has been synthesised and is now available commercially, its use in the pathophysiology of pregnancy remains controversial. One of these concerns is the way in which the hormone is administered, with parenteral use proving the best way to obtain optimal plasma levels. Another concern is the paucity of randomised controlled trials and the different dosages and populations studied. As a result, the therapeutic application of progesterone in pregnancy is restricted to the prevention and treatment of threatened miscarriage, recurrent miscarriage and preterm birth. Progesterone is efficacious when continuation of pregnancy is hampered by immunological factors, luteinic and neuroendocrine deficiencies and myometrial hypercontractility. This may explain the reduction in the incidence of preterm birth in high risk pregnant women using high‐dosage prophylactic progesterone.
Can antibiotics prevent preterm birth—the pro and con debate
Authors: Lamont Ronnie F.
Published: February 2005

Studies using different diagnostic methods and outcome parameters have used different antibiotics and dose/administration regimes to women of differing risk of preterm birth with, not surprisingly, different results. Studies which have shown benefit have been criticised for having either poor methodology, low sample size or having only showed benefit after a non‐prespecified subgroup analysis. Studies which have failed to show any benefit have been criticised for unacceptable methods of diagnosing abnormal genital tract flora or having excluded a large percentage of patients eligible for the study, for having permitted a long period to elapse from diagnosis of abnormal genital tract flora to administration of treatment and for having employed treatment too late in pregnancy. A Cochrane Systematic Review of these studies failed to provide a definitive answer because this was published one month before two randomised double‐blind placebo‐controlled trials were published, in which clindamycin used either systemically or intravaginally in low risk, unselected women resulted in a 60% reduction in the incidence of preterm birth. This would have influenced the inconclusive results of the Cochrane review, with respect to general population studies. Very early spontaneous preterm labour and preterm birth is more likely to be of infectious aetiology than preterm birth just before term. The earlier in pregnancy at which abnormal genital tract flora is detected, the greater is the risk of an adverse outcome. Women with abnormal flora in early pregnancy, who subsequently revert to normal, continue to have a high risk of adverse outcome of pregnancy, at a degree similar to women with abnormal genital tract flora in early pregnancy who were treated with placebo. This suggests that whatever damage abnormal flora induces, this is at an early gestation, even if the flora subsequently reverts to normal. It follows therefore that if antibiotics are to be of help in preventing spontaneous preterm labour and preterm birth of infectious aetiology, these must be administered early in pregnancy. Antibiotics used prophylactically for the prevention of preterm birth are more likely to be successful if: they are used in women with abnormal genital tract flora (rather than other risk factors for preterm birth, e.g. low BMI, twins, generic previous preterm birth); they are used early in pregnancy prior to infection (tissue penetration/inflammation and tissue damage); they are used in women with the greatest degree of abnormal genital tract flora; and if they are used in women with a predisposition to mount a damaging inflammatory response to infection.
Combination therapy
Authors: Ingemarsson Ingemar
Published: February 2005

Objective  Inhibiting preterm labour at extremely early gestations.

Design  Observational study. Case reports.

Setting  Perinatal Centre Lund University Hospital, South Sweden.

Population  Twenty‐five women (13 cases with intact membranes and 12 cases with ruptured) with threatened preterm labour and advanced cervical status before 26 completed weeks of gestation.

Methods  A combination of different drugs was used. Atosiban, an oxytocin antagonist, was the first line drug and was given as an infusion for several days as required. Supportive therapy was also given to most women with subcutaneous injections of the β‐receptor agonist terbutaline (0.25 mg up to six times a day); sulindac, a prostaglandin synthetase inhibitor (200 mg one to two times a day up to a week); and broad‐spectrum antibiotics (metronidazole and cefuroxime intravenously for three days and thereafter oral therapy).

Main outcome measures  Prolongation of pregnancy more than 48 hours or 7 days. Neonatal survival.

Results  Prolongation of pregnancy for more than 48 hours to enable administration of corticosteroid therapy was obtained in all but three cases. Eight women were delivered after more than a week from admission. Three neonates died at birth due to obstetric complication or sepsis. The other neonates had normal pH in cord or venous blood at birth. No severe side effects were recorded and in no case did the treatment have to be discontinued due to side effects.

Conclusion  The policy described here is not evidence based, relating only to clinical observations, and as such is of very limited value. However, it seems that with this combined approach to management, some days can be gained by achieving full effect of corticosteroid treatment and prolongation of the pregnancy, hopefully reducing time in the neonatal intensive care in these critical cases. No severe side effects were reported.
LFRFamides: a novel family of parasitation‐induced ‐RFamide neuropeptides that inhibit the activity of neuroendocrine cells in Lymnaea stagnalis
Authors: Hoek R. M. , Li K. W. , Van Minnen J. , Lodder J. C. , De Jong‐Brink M. , Smit A. B. , Van Kesteren R. E.
Published: February 2005

We report the characterization of a cDNA encoding a novel ‐RFamide neuropeptide precursor that is up‐regulated during parasitation in the snail Lymnaea stagnalis. Processing of this precursor yields five structurally related neuropeptides, all but one ending with the C‐terminal sequence ‐LFRFamide, as was confirmed by direct mass spectrometry of brain tissue. The LFRFamide gene is expressed in a small cluster of neurons in each buccal ganglion, three small clusters in each cerebral ganglion, and one cluster in each lateral lobe of the cerebral ganglia. Application of two of the LFRFamide peptides to neuroendocrine cells that control either growth and metabolism or reproduction induced similar hyperpolarizing K+‐currents, and inhibited electrical activity. We conclude that up‐regulation of inhibitory LFRFamide neuropeptides during parasitation probably reflects an evolutionary adaptation that allows endoparasites to suppress host metabolism and reproduction in order to fully exploit host energy recourses.
Cellular and subcellular calcium accumulation during glutamate‐induced injury in cerebellar granule neurons
Authors: Ward Manus W. , Kushnareva Yulia , Greenwood Sam , Connolly Christopher N.
Published: February 2005

We have investigated the role of Ca2+ accumulation and neuronal injury in cerebellar granule neurons after glutamate receptor overactivation. After the removal of the free cytosolic Ca2+ we identified an extensive second Ca2+ fraction (SCF) that is retained within the neurons after glutamate receptor overactivation. The SCF reaches a plateau within 10 min with the magnitude of this SCF accumulation reflecting the extent of the neuronal injury that occurs within the neurons. The existence of this SCF is sensitive to both NMDA receptor antagonists and mitochondrial inhibitors but is unaffected by agents that deplete endoplasmic reticulum Ca2+, indicating that this Ca2+ fraction may be located within the mitochondria. Through the isolation of mitochondria from cerebellar granule neurons treated with glutamate we have shown that the majority of the SCF is mitochondrial in location. On the removal of the glutamate stimulus the SCF recovers at a slower rate than the free Ca2+ concentration within the neuron. This is intriguing, as it implies a capacity to remember previous excitatory events. Most significantly we have shown that a short pre‐application of subthreshold glutamate or kainate blocks both SCF Ca2+ accumulation and extensive neuronal injury in response to high concentrations of glutamate. These findings may be relevant to the observations of pre‐conditioning in the brain and heart.
Increased cyclin E expression may obviate the role of cyclin D1 during brain development in cyclin D1 knockout mice
Authors: Chen Zhiguo , Duan Rui‐Sheng , Zhu Yu , Folkesson Ronnie , Albanese Chris , Winblad Bengt , Zhu Jie
Published: February 2005

Cyclins D and E play critical roles during the G1 phase of mammalian cell division. Cyclin D1 expression is high and expected to play an important role during mouse brain development. However, in the present study, we found no difference in CNS morphology between cyclin D1 knockout (KO) and control wild‐type mice at the ages of 1, 4 and 12 months. Analysis of protein expression in embryonic brains revealed that cyclin E is obviously increased in cyclin D1 KO mice at 13.5 days post coitum. At the same age a high level of cyclin D1 expression is detected in the embryonic brain of wild‐type mice. The data indicate that enhanced cyclin E protein expression in cyclin D1 KO mice may obviate the role of cyclin D1 and contribute to the normal brain development of cyclin D1 KO mice.
Axonal transport of the cellular prion protein is increased during axon regeneration
Authors: Moya Kenneth L. , Hässig Raymonde , Breen Kieran C. , Volland Hervé , Di Giamberardino Luigi
Published: February 2005

The cellular prion protein, PrPc, is a glycosylphosphatidylinositol‐anchored cell surface glycoprotein and a protease‐resistant conformer of the protein may be the infectious agent in transmissible spongiform encephalopathies. PrPc is localized on growing axons in vitro and along fibre bundles that contain elongating axons in developing and adult brain. To determine whether the growth state of axons influenced the expression and axonal transport of PrPc, we examined changes in the protein following post‐traumatic regeneration in the hamster sciatic nerve. Our results show (1) that PrPc in nerve is significantly increased during nerve regeneration; (2) that this increase involves an increase in axonally transported PrPc; and (3) that the PrPc preferentially targeted for the newly formed portions of the regenerating axons consists of higher molecular weight glycoforms. These results raise the possibility that PrPc may play a role in the growth of axons in vivo, perhaps as an adhesion molecule interacting with the extracellular environment through specialized glycosylation.
Identification of complement 5a‐like receptor (C5L2) from astrocytes: characterization of anti‐inflammatory properties
Authors: Gavrilyuk Vitaliy , Kalinin Sergey , Hilbush Brian S. , Middlecamp Andrew , McGuire Susan , Pelligrino Dale , Weinberg Guy , Feinstein Douglas L.
Published: February 2005

Brain inflammation is regulated by endogenous substances, including neurotransmitters such as noradrenaline (NA), which can increase anti‐inflammatory genes. To identify NA‐regulated, anti‐inflammatory genes, we used TOGA (total gene expression analysis) to screen rat astrocyte‐derived RNA. NA‐inducible cDNA clone DST11 encodes an isoform of the complement C5a receptor (C5aR), with 39% identity at the amino acid level to the rat C5aR, and 56% identity to a recently described human C5aR variant termed C5L2 (complement 5a‐like receptor). Quantitative PCR confirmed that in astrocytes, DST11 mRNA expression is increased by NA, whereas in vivo depletion of cortical NA reduced DST11 levels. Western blot analysis demonstrated basal and NA‐induced expression of DST11 as a 45 kDa protein in primary astrocytes cultures. Immunocytochemical staining of adult rat brain revealed DST11‐immunoreactivity throughout brain, co‐localized to neurons and astrocytes. In astrocytes, induction of nitric oxide synthase type 2 was increased by treatment with antisense oligonucleotides to DST11. Reducing DST11 expression also increased nuclear factor κB reporter gene, and decreased cAMP response element reporter gene activation. These results demonstrate that DST11 is a C5aR isoform expressed by glia and neurons, which is regulated by NA, and exerts anti‐inflammatory functions. Changes in DST11 levels in diseased brain could therefore contribute to the progression of inflammatory damage.
Mechanism of zinc‐induced phosphorylation of p70 S6 kinase and glycogen synthase kinase 3β in SH‐SY5Y neuroblastoma cells
Authors: An Wen‐Lin , Bjorkdahl Cecilia , Liu Rong , Cowburn Richard F. , Winblad Bengt , Pei Jin‐Jing
Published: February 2005

We have previously reported an aberrant accumulation of activated protein kinase B (PKB), glycogen synthase kinase (GSK)‐3β, extracellular signal‐regulated kinase (ERK1/2), c‐Jun N‐terminal kinase (JNK), p38 and p70 S6 kinase (p70S6K) in neurons bearing neurofibrillary tangles (NFTs) in Alzheimer's disease (AD). However, the mechanism by which these tau candidate kinases are involved in the regulation of p70S6K and GSK‐3β phosphorylation is unknown. In the current study, 100 μm zinc sulfate was used, and influences of various components of phosphatidylinositol 3‐kinase (PI3K) and mitogen‐activated protein kinase (MAPK) pathways on p70S6K and GSK‐3β phosphorylation have been investigated in serum‐deprived SH‐SY5Y neuroblastoma cells. We found that zinc could induce an increase of phosphorylated (p) p70S6K, p‐PKB, p‐GSK‐3β, p‐ERK1/2, p‐JNK and p‐p38, especially in long‐term treatment (4–8 h). Treatment with different inhibitors including rapamycin, wortmannin, LY294002, and U0126, and their combinations, indicated that phosphorylation of p70S6K and GSK‐3β is regulated by rapamycin‐dependent, PI3K and MAPK pathways. Furthermore, phosphorylation of p70S6K and GSK‐3β affected levels of tau unphosphorylated at the Tau‐1 site and phosphorylated at the PHF‐1 site, and p70S6K phosphorylation affected the total tau level. Thus, 100 μm zinc might activate PKB, GSK‐3β, ERK1/2, JNK, p38 and p70S6K, that are consequently involved in tau changes in SH‐SY5Y cells.
Sleep deprivation induces the unfolded protein response in mouse cerebral cortex
Authors: Naidoo Nirinjini , Giang William , Galante Raymond J. , Pack Allan I.
Published: February 2005

Little is known about the molecular mechanisms underlying sleep. We show the induction of key regulatory proteins in a cellular protective pathway, the unfolded protein response (UPR), following 6 h of induced wakefulness. Using C57/B6 male mice maintained on a 12:12 light/dark cycle, we examined, in cerebral cortex, the effect of different durations of prolonged wakefulness (0, 3, 6, 9 and 12 h) from the beginning of the lights‐on inactivity period, on the protein expression of BiP/GRP78, a chaperone and classical UPR marker. BiP/GRP78 expression is increased with increasing durations of sleep deprivation (6, 9 and 12 h). There is no change in BiP/GRP78 levels in handling control experiments carried out during the lights‐off period. PERK, the transmembrane kinase responsible for attenuating protein synthesis, which is negatively regulated by binding to BiP/GRP78, is activated by dissociation from BiP/GRP78 and by autophosphorylation. There is phosphorylation of the elongation initiation factor 2α and alteration in ribosomal function. These changes are first observed after 6 h of induced wakefulness. Thus, prolonging wakefulness beyond a certain duration induces the UPR indicating a physiological limit to wakefulness.
In vivo gene silencing of CD81 by lentiviral expression of small interference RNAs suppresses cocaine‐induced behaviour
Authors: Bahi Amine , Boyer Frederic , Kolira Manoj , Dreyer Jean‐Luc
Published: February 2005

The tetraspanin CD81 is induced in the mesolimbic dopaminergic pathway after cocaine administration. To further investigate its role, a regulatable lentivirus (Lenti‐CD81) bearing the CD81 gene under the control of a tetracycline‐inducible promoter and lentiviruses expressing short hairpin RNA (shRNA) targeted against CD81 (Lenti‐CD81‐shRNAs) have been prepared. Infection of HEK293T cells in vitro with Lenti‐CD81‐shRNAs resulted in 96.5% gene silencing (from quantitative real‐time PCR(qRT‐PCR) and immunocytochemistry). In vivo delivery of Lenti‐CD81‐shRNA into the nucleus accumbens or ventral tegmental area resulted in 91.3 and 94% silencing of endogenous CD81, respectively. Stereotaxic injection of Lenti‐CD81 into these regions, resulting in CD81 overexpression, induced a four‐ to fivefold increase in locomotor activity after chronic cocaine administration, which returned to basal levels when Lenti‐CD81‐shRNA had been coinjected or when CD81 expression was blocked by doxycycline. Furthermore, silencing endogenous CD81 in vivo resulted in a significant decrease in locomotor activity over controls, again suppressing cocaine‐induced behaviour.
Determination of pseudophakic accommodation with translation lenses using Purkinje image analysis
Authors: Langenbucher Achim , Jakob Christina , Reese Sven , Seitz Berthold
Published: February 2005

Purpose:  To determine pseudophakic accommodation of an accommodating posterior chamber intraocular lens (translation lens) using Purkinje image analysis and linear matrix methods in the paraxial space.

Methods:  A 2 × 2 system matrix was defined for each Purkinje image I to IV using refraction, translation and mirror matrices. Image size (m) and axial image position (z) was determined as an example for an off‐axis object (a 0.2 m off‐axis object located 0.5 m in front of the cornea.). First, our method was applied to the phakic relaxed (emmetropic) and accommodated (6.96 D) Le Grand eye. Secondly, for demonstration of the applicability of the calculation scheme to the pseudophakic eye, we provide a clinical example where we determine the accommodation amplitude of the translation lens (1 CU, HumanOptics, Erlangen, Germany) from photographed Purkinje images in the relaxed and accommodated state. From the biometric data: axial length 23.7 mm, corneal power 43.5, corneal thickness 550 microns, implanted intraocular lens (IOL) with a refractive power of 20.5 D (shape equi‐biconvex, refractive index 1.46), and refractive indices of the cornea, aqueous and vitreous from the Le Grand model eye, we calculated the refractive state and the sizes of Purkinje images I and III initiated from two off‐axis light sources.

Results:  For the Le Grand model eye, Purkinje image II (z/m = 3.5850 mm/0.0064) is slightly smaller than and directly in front of image I (z/m = 3.8698 mm/0.0077). Purkinje image III (z/m = 10.6097 mm/0.0151) is nearly double the size of image I and during accommodation it moves from the vitreous into the crystalline lens. Purkinje IV (z/m = 4.3244 mm/−0.0059) is inverted, three quarters the size of image I, lies in the crystalline lens and moves slightly towards the retina. For the pseudophakic eye, pseudophakic accommodation of 1.10 D was calculated from the proportion of distances between both Purkinje images I and III in the relaxed (3.04) and accommodated (2.75) state, which is in contrast to the total subjective accommodation of 2.875 D evaluated with an accommodometer.

Conclusions:  We present a straightforward mathematical strategy for calculation of the Purkinje images I–IV. Results of our model calculation resemble the values provided by Le Grand. In addition, this approach yields a simple en bloc scheme for determination of pseudophakic accommodation in pseudophakic eyes with accommodative lenses (translation lenses) using Purkinje image photography.
Use of prisms for navigation and driving in hemianopic patients
Authors: Szlyk Janet P. , Seiple William , Stelmack Joan , McMahon Timothy
Published: February 2005

Purpose:  (1) To compare the outcomes of orientation and mobility and driving training with Fresnel prisms and the Gottlieb Visual Field Awareness System for patients with homonymous hemianopsia, and (2) To determine whether the patients continue to use the optical enhancement devices at a 2‐year follow‐up point.

Methods:  Patients with homonymous hemianopsia were provided with a rehabilitation program where they were fitted with prism lenses and trained to use them for navigation and driving. Telephone interviews were used to obtain information about device usage 2 years following the completion of the training program.

Results:  Patients’ performance was compared with a test–retest criterion in the visual skills areas of recognition, mobility, peripheral detection, scanning, tracking, and visual memory. Patients with hemianopic loss showed improvements in all of the visual skills categories, ranging from the highest improvements of 26% of tasks improved in the mobility category to 13% in the recognition category. The majority of the hemianopic patients reported using the devices at the 2‐year follow‐up interview.

Conclusions:  The patients with homonymous hemianopsia showed improvements in visual functioning using prism lenses, although these improvements were smaller than those found in previous studies with central or bilateral peripheral vision loss groups who were trained to use other optical enhancement devices for navigation and driving using a similar curriculum. However, given the evidence of increased risk of accidents for patients with peripheral vision loss, the safety of peripheral enhancement devices for driving must be thoroughly evaluated before their impact on public safety is known.
Non‐invasive phakometric measurement of corneal and crystalline lens alignment in human eyes
Authors: Dunne Mark C. M. , Davies Leon N. , Mallen Edward A. H. , Kirschkamp Thomas , Barry Jean‐Cyriaque
Published: February 2005

We describe a non‐invasive phakometric method for determining corneal axis rotation relative to the visual axis (β) together with crystalline lens axis tilt (α) and decentration (d) relative to the corneal axis. This does not require corneal contact A‐scan ultrasonography for the measurement of intraocular surface separations. Theoretical inherent errors of the method, evaluated by ray tracing through schematic eyes incorporating the full range of human ocular component variations, were found to be larger than the measurement errors (β < 0.67°, α < 0.72° and d < 0.08 mm) observed in nine human eyes with known ocular component dimensions. Intersubject variations (mean ± S.D.: β = 6.2 ± 3.4° temporal, α = 0.2 ± 1.8° temporal and d = 0.1 ± 0.1 mm temporal) and repeatability (1.96 × S.D. of difference between repeat readings: β ± 2.0°, α ± 1.8° and d ± 0.2 mm) were studied by measuring the left eyes of 45 subjects (aged 18–42 years, 29 females and 16 males, 15 Caucasians, 29 Indian Asians, one African, refractive error range −7.25 to +1.25 D mean spherical equivalent) on two occasions.
Comparison of near heterophoria tests under varying conditions on an adult sample
Authors: Lam Andrew K. C. , Lam Abby , Charm Jessie , Wong Kwai‐mui
Published: February 2005

Purpose:  This study compared the near phoria measurement using the Bernell muscle balance card with and without prism neutralization, using both trial frame and phoropter correction, and compared with the conventional Maddox rod method.

Methods:  Forty young normal Chinese adults had their near phoria measured with trial frame correction using the conventional muscle balance card method (method 1). Any deviation was compensated with a prism bar as an alternative approach (method 2). The conventional Maddox rod method (method 3) was also carried out for comparison. These three methods were repeated with phoropter correction and considered as methods 4, 5 and 6.

Results:  The phorias obtained from these six methods were not significantly different from each other (repeated measures anova, p > 0.05). More than half of the subjects were exophoric. Although the difference in phoria was not significant, phoria measurement using phoropter correction yielded a greater coefficient of variation.

Conclusions:  Near phoria measurement using the muscle balance card conducted with trial frame correction was less variable, and was also more natural and similar to a real reading situation. The use of prism for compensation did not affect the phoria results. Exophoria seems to be more common than esophoria in young Chinese adults.
Attachments to Family and Community and the Young Adult Transition of Rural Youth
Authors: Kirkpatrick Johnson Monica , Elder Glen H. , Stern Michael
Published: February 2005

Rural youth in economically troubled regions develop plans for their future in a context in which opportunities for educational and occupational success generally lie elsewhere, prompting the need to migrate. This study investigates the links between rural adolescents' residential preferences and their plans for the future, perceptions of local opportunity, and ties to family and community. We examine whether residential preferences shape the pathways to adulthood through decisions about where to live as well as educational and occupational attainments. Residential preferences are indeed related to adolescents' academic achievements and future educational plans, their relationships with parents, and perceptions of local job opportunities, but they are not associated with family socioeconomic background and social ties to the community. For the most part, residential preferences are linked to where young people live and pursue higher education in the years after high school, but generally not to their socioeconomic attainment.
Staying Vietnamese: Community and Place in Orange County and Boston
Authors: Aguilar‐San Juan Karin
Published: February 2005

Orange County, California, is a “postsuburban” region known for its sprawl and its cultural homogeneity. There, Vietnamese Americans have established a large commercial and residential district clearly marked by freeway signs, recognized by city government, and labeled the “Capital of Vietnamese America.” On the other hand, in Boston, Massachusetts, an old city known for its neighborhoods teeming with immigrants, Vietnamese Americans have had difficulty in establishing a distinct and identifiable place. Bostonians who are not Vietnamese may not know that Fields Corner is the city's “Vietnamese village.” Since Boston's Chinatown also contains Vietnamese, the distinction between Fields Corner and Chinatown can be blurry. Could it be that each community actually reverses the dynamics of place in each region—creating a strong, central place in a culturally homogenous and spatially decentralized post‐suburb, but failing to create a very strong place in an old city reputed for its immigrant neighborhoods? If so, a paradox appears. I identify the patterns involving community and place that have produced paradoxical outcomes in Orange County and Boston. I show that Vietnamese American leaders use place—as a site for interaction, as an anchor for identity, and as a symbol of belonging—to define and strengthen their communities. I argue that part of “becoming American” requires “staying Vietnamese,” and that place making is key to this process.
The Upper Sonoran Lifestyle: Gated Communities in Scottsdale, Arizona
Authors: Romig Kevin
Published: February 2005

While much has been written on gated communities and the motivations and proposed implications of such a building paradigm, little has informed us about how a landscape is socially and economically transformed by the influx of this community design principle. This article explores a place defined by gated communities highlighting significant differences in social and community life in the city of Scottsdale, Arizona. This is a location, unlike many other gated spaces, where the gating of the community has little to do with avoiding crime. It is mainly a symbol of prestige and exclusivity. Housing in the Northern part of Scottsdale is mostly gated, master‐planned communities geared toward the upper class while the Southern part of Scottsdale is comprised of older housing stock and more organic community life. Both primary and secondary data are analyzed to highlight the socio‐cultural nature of the Upper Sonoran landscape. This article also explores social theory and proposes the use of multi‐scalar thinking and grounded fieldwork in gathering a more detailed, multi‐dimensional picture of community life behind the gate. This picture illustrates the changing nature of institutional forces shaping urban life as neoliberal policies in local government engender the proliferation of private institutions, as residents are willing to relinquish personal property rights for economic and social stability.
Toward a Biopsychosocial Model for 21st‐Century Genetics
Authors: Rolland John S. , Williams Janet K.
Published: February 2005

Advances in genomic research are increasingly identifying genetic components in major health and mental health disorders. This article presents a Family System Genetic Illness model to address the psychosocial challenges of genomic conditions for patients and their families, and to help organize this complex biopsychosocial landscape for clinical practice and research. This model clusters genomic disorders based on key characteristics that define types of disorders with similar patterns of psychosocial demands over time. Key disease variables include the likelihood of developing a disorder based on specific genetic mutations, overall clinical severity, timing of clinical onset in the life cycle, and whether effective treatment interventions exist to alter disease onset and/or progression. For disorders in which carrier, predictive, or presymptomatic testing is available, core nonsymptomatic time phases with salient developmental challenges are described pre‐ and post‐testing, including a long‐term adaptation phase. The FSGI model builds on Rolland's Family System Illness model, which identifies psychosocial types and phases of chronic disorders after clinical onset. The FSGI model is designed to be flexible and responsive to future discoveries in genomic research. Its utility is discussed for research, preventive screening, family assessment, treatment planning, and service delivery in a wide range of healthcare settings.
Critical Consciousness, Accountability, and Empowerment: Key Processes for Helping Families Heal
Authors: Hernández Pilar , Almeida Rhea , Dolan‐Del Vecchio Ken
Published: February 2005

Families are inextricably embedded within their larger sociopolitical contexts, an observation acknowledged by many theorists. The field of family therapy is working on its translation into comprehensive and effective approaches for helping families change. This article illustrates the use of the Cultural Context Model to help families change, guided by the linked foundational concepts of accountability, critical consciousness, and empowerment. The authors support their discussion of theory with examples illustrating the ways in which social patterns connected to race, gender, class, and sexual orientation shape the dilemmas that family members encounter, as well as their access to solutions.
Co‐constructing a Cross‐Cultural Course: Resisting and Replicating Colonizing Practices
Authors: Bors̆tnar Jana , Moc̆nik Buc̆ar Mojca , Makovec Maja Rus , Burck Charlotte , Daniel Gwyn
Published: February 2005

This article examines the cross‐cultural complexities of teaching and learning processes at different levels in a family therapy training program delivered in a different country. It presents two interlinked narratives of an advanced family therapy training program delivered in Slovenia by a U.K.‐based family therapy training institute. The context in which the training was negotiated and planned is discussed, highlighting issues at the macrosystemic level. Dilemmas that arose in relation to differing beliefs about teaching and learning are elaborated. We examine power relationships, ways that we positioned ourselves and each other, and how we tried and sometimes failed to take these into account. We question how the issue of spoken language and its meanings creates its own constraints and power structures, and how we respond to the impossibilities of translation. We argue that it is through the examination of uncomfortable processes that we develop self‐reflexivity and work toward more equitable relationships.
Passive Oxidation of an Effluent System: The Case of Polymer‐Derived SiCO
Authors: Modena Stefano , Sorarù Gian Domenico , Blum Yigal , Raj Rishi
Published: February 2005

The oxidation kinetics of non‐oxides depend on the inward diffusion of oxygen from the environment through the passivating silica overgrowth, the outward diffusion of the effluent species, e.g., CO, produced by the oxidation reaction at the interface, and the chemical driving forces for diffusion. An analysis that combines these factors into a unified theory is presented. The analysis is applied to experiments on the oxidation of polymer‐derived amorphous silicon oxycarbide (SiCO) ceramics containing different amounts of carbon. The comparison between theory and experiment suggests that the activity of the so‐called “free carbon” in SiCO is likely to be less than unity, which explains why the oxidation of SiCO is passive in nature. Further, the analysis provides quantitative answers to the following questions: (a) How is the effective diffusivity for the parabolic rate constant related to the composition of the substrate, the inward diffusivity of oxygen, and the outward diffusivity of CO? (b) How does the rate constant depend on the activity of carbon in the substrate and on the activity of carbon in the environment? (c) How is the pressure of CO generated at the interface related to the carbon activity and the diffusion coefficients? The analysis points towards the need for systematic experiments in controlled O2/CO2 environments for a more complete understanding of the oxidation kinetics of carbon‐based ceramics.
Microstructure and Properties of Co2+: ZnAl2O4/SiO2Nanocomposite Glasses Prepared by Sol–Gel Method
Authors: Duan Xiu‐Lan , Yuan Duo‐Rong , Cheng Xiu‐Feng , Sun Hai‐Qing , Sun Zhi‐Hong , Wang Xin‐Qiang , Wang Zeng‐Mei , Xu Dong , Lv Meng‐Kai
Published: February 2005

Transparent bulk Co2+: ZnAl2O4/SiO2nanocomposites containing nanocrystalline Co2+: ZnAl2O4dispersed in silica glass matrix were obtained by the sol–gel method. The gels of composition 89SiO2–6Al2O3–5ZnO−xCoO (x=0.2, 0.4, 0.6, 0.8, 1.0) (mol%) were prepared at room temperature by using two different aluminum salts, aluminum nitrate and aluminum alkoxide (aluminum‐iso‐propoxide, Al(OPri)3), as starting materials. The transparent gels were converted to the crystalline phase of gahnite by heating above 900°C. The microstructural evolution of gels was characterized. The effect of Co2+concentration on spectroscopic properties was also discussed. Co2+: ZnAl2O4nanocrystals dispersed in the SiO2‐based glass are formed at lower heat‐treatment temperature and shorter heating time by using Al(OPri)3as raw material.
The Role of TiN in the Intergranular Phase‐Forming Process in TiN‐Dispersed Si3N4 Nanocomposites
Authors: Schmid Herbert K.
Published: February 2005

Internal interfaces in two ceramic systems, monolithic Si3N4 (SN) and TiN‐dispersed Si3N4 nanocomposite (STN), were characterized by analytical transmission electron microscopy (TEM). In monolithic SN both MgO and Y2O3 dopants are preferentially hosted by the vitreous intergranular phase in pockets at triple grain junctions (TJ), whereas in STN composites the highest dopant concentrations were observed in grain and phase boundaries. The width of grain boundary films, as revealed by high‐resolution TEM imaging, varied between ≈0.8 nm in monolithic SN and ≈1.0–1.2 nm in STN. Intergranular films with increased width ≈1.8 nm were detected in SN–TiN phase boundaries. Although no enrichment of Ti could be detected in the intergranular phase, it appears that the presence of TiN dispersants indirectly contributes to the intergranular phase formation. It is assumed that TiO2 impurities sitting on TiN particle surfaces react with the matrix phase, resulting in a more oxidic nature of intergranular films due to increased SiO2 supply in intergranular regions. Phase‐specific Si‐L2,3 energy‐loss near edge structure features, which could serve as fingerprints for phase identification, were observed in spatial‐difference electron energy‐loss spectra from grain boundary films and TJ pockets.
Effects of Porosity on the Threshold Strength of Laminar Ceramics
Authors: Pontin Michael G. , Lange Fred F.
Published: February 2005

Ceramic laminates exhibiting a threshold strength have been fabricated by dip‐coating thick tape‐cast Al2O3 layers into slurries containing mixtures of Al2O3 and either unstabilized zirconia (MZ‐ZrO2) or mullite to produce thin compressive layers via both a molar volume change and a differential thermal contraction. Porosity was introduced into the thin compressive layers by adding rice starch to the dip‐coating slurries, which decomposed during densification of the laminate. As the volume fraction of porosity is increased, the residual compressive stress (σC), as measured by piezospectroscopy, is reduced and approaches zero at approximately 0.65 volume fraction of porosity. The elastic modulus mismatch (E1/E2) between the thin and thick laminate layers accounted for approximately one‐half of the threshold strength for volume fractions of porosity ≤0.30 (E1/E2<0.4). Above 0.40 volume fraction of porosity, the strength significantly increased as did the scatter in strength values, and it was observed that the highly porous layers completely arrested crack extension; these materials no longer exhibited a threshold strength. For these laminates, failure occurred by the independent, sequential failure of one layer after another, followed by catastrophic failure due to delamination.
Toughening of 8Y‐FSZ Ceramics by Neodymium Titanate Secondary Phase
Authors: Liu Xiao Qiang , Chen Xiang Ming
Published: February 2005

The effects of Nd2Ti2O7 additive on the microstructure and mechanical properties of 8‐mol%‐yttria‐doped fully stabilized zirconia (8Y‐FSZ) ceramics were investigated. The Nd2Ti2O7 secondary phase was able to coexist with the 8Y‐FSZ matrix, and the fracture toughness of the 8Y‐FSZ ceramics was significantly improved by the Nd2Ti2O7 addition.
Synthesis of Silicon Carbide Nanotubes
Authors: Taguchi T. , Igawa N. , Yamamoto H. , Jitsukawa S.
Published: February 2005

Single‐phase silicon carbide (SiC) nanotubes were successfully synthesized by the reaction of carbon nanotubes with silicon powder at 1200°C for 100 h. X‐ray diffraction patterns indicated that most of the carbon from the carbon nanotubes that were reacted with silicon at 1200°C for 100 h was transformed to SiC. Transmission electron microscopy observations revealed that both single‐phase SiC nanotubes and C–SiC coaxial nanotubes, which are carbon nanotubes sheathed with a SiC layer, were synthesized after 100 h of reaction. The ratio of single‐phase SiC nanotubes to C–SiC nanotubes increased with heat treatment at 600°C in air for 1 h because the remaining carbon was removed.