bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron emission properties of relaxation-induced traps in InAs/GaAs quantum dots and the effect of electronic band structure
Authors: Chen J. F. , Wang J. S.
Published: August 2007

The electron-emission properties of relaxation-induced traps in InAs/GaAs quantum dots (QDs) are studied in detail using capacitance-voltage (C-V) profiling and bias-dependent deep-level transient spectroscopy. Strain relaxation is shown to induce a threading-dislocation-related trap in the top GaAs layer and a misfit-dislocation-related trap near the QD. The threading trap decreases its electron-emission energy from 0.63 to 0.36 eV from sample surface toward the QD, whereas the misfit trap gradually increases its electron-emission energy from 0.28 to 0.42 eV from near the QD toward the GaAs bottom layer, indicating that both traps near the QD have lower electron-emission energies. Hence, the emission-energy change is attributed to the related traps across the QD interface where a band offset exists. The C-V profiling at 300 K shows extended carrier depletion near the QD. As temperature is increased, an electron-emission peak emerges at the QD followed by a prominent peak, suggesting that the trap responsible for the prominent peak lies in energy below the QD electron ground state. From a simulation, this trap is identified to be the misfit trap located at the QD and at the observed emission energy below the GaAs conduction band. Based on the energy location of this trap, we deduce a possible mode of strain relaxation.
Calculations of energy gap and optical transitions in (001) quantum films of diamond: Quantum-confinement and surface effects
Authors: Nishida Masahiko
Published: August 2007

The electronic structure of diamond (001) ultrathin quantum films terminated by monohydrogenated dimers on both surfaces with 2×1 periodicity is studied by the extended Hückel-type nonorthogonal tight-binding method. In all diamond films studied, an unoccupied surface-related state occurs just below the conduction-band minimum of bulk diamond at the center of the (001) surface Brillouin zone (SBZ). It is shown that, although the band gap in bulk diamond is indirect, a direct energy gap is created between the film valence-band maximum and the lowest unoccupied surface state at the SBZ center by both quantum-confinement and surface effects. It is also demonstrated that optical transitions across the energy gap are dipole allowed and exhibit significantly high oscillator strength.
Structural analysis of zinc phthalocyanine (ZnPc) thin films: X-ray diffraction study
Authors: Senthilarasu S. , Hahn Y. B. , Lee Soo-Hyoung
Published: August 2007

X-ray diffraction (XRD) was used to analyze the structure of thermally evaporated zinc phthalocyanine (ZnPc) organic thin films, as functions of the substrate temperature and film thickness. A metastable α to stable β phase transformation has been observed when the films are coated at higher substrate temperatures. The core structure of the zinc phthalocyanine macrocycle is formed by four isoindole units, which endows the molecule with a two-dimensional conjugated π electron system. The structural analysis and high-resolution transmittance electron microscope images, along with simulation, support the formation of molecular arrays, with the electronic structure fixing the molecular spacing and producing mainly parallel arrays in small domains. These arrays produce the frontier orbital gap, which match the experimental values, and also the experimental data of periodicity, which can be reproduced theoretically.
Photorefractive organic material for optical thresholding
Authors: Talarico M. , Termine R. , Golemme A.
Published: August 2007

The authors studied the photorefractive performance of bistable surface stabilized chiral smectic C cells doped with C70. Diffraction efficiency strongly depends on the combination of (a) the application time of the electric field used during the writing process and (b) light intensity. By choosing the conditions of the writing process, gratings with high efficiency can form only for certain levels of light intensity.
Optical and structural properties of Si nanocrystals produced by Si hot implantation
Authors: Sias U. S. , Behar M. , Boudinov H. , Moreira E. C.
Published: August 2007

It was already demonstrated that Si hot implantation followed by high-temperature annealing induces the formation of Si nanocrystals (Si NCs) which when excited in a linear excitation regime present two photoluminescence (PL) bands (at 780 and 1000 nm). We have undertaken the present work in order to investigate three features: First, to determine the origin of each band. With this aim we have changed the implantation fluence and the high-temperature annealing time. Second, to investigate the influence of the postannealing atmosphere on the PL recovering process after bombarding the Si NCs. Third, we have annealed the as-produced Si NCs in a forming gas (FG) atmosphere in order to observe the PL behavior of each band. The results have shown that the 780 nm PL band has its origin in radiative interfacial states, while the 1000 nm one is due to quantum size effects. From the experiments we have concluded that the PL recovery after the Si NCs irradiation strongly depends on the type of postannealing atmosphere. Finally, it was found that the FG treatment strongly affects the line shape of the PL spectrum.
Dynamical thermal conductivity of argon crystal
Authors: Kaburaki Hideo , Li Ju , Yip Sidney , Kimizuka Hajime
Published: August 2007

The thermal conductivity of a rare-gas crystal (Ar) is computed using equilibrium molecular dynamics in conjunction with the Green-Kubo linear response formalism, and the Lennard-Jones potential with an appropriately long cutoff (4σ). Besides predicting absolute values of the conductivity from low temperature up to the liquid, the approach allows heat conduction to be understood as a dynamical process through the temporal behavior of the heat current correlation function. At low temperatures the correlation function shows a characteristic two-stage decay, a short-time relaxation which we attribute to single-particle motions in a local environment, and a more extended component corresponding to collective atomic motions (phonons). As temperature increases the second correlation component diminishes much faster than the first component, indicating a transition from mainly phase-coherent phonon transport to mainly phase-incoherent interatomic energy transfer in solids.
InAs-coverage dependence of self-assembled quantum dot size, composition, and density
Authors: Zolotaryov A. , Schramm A. , Heyn Ch. , Hansen W.
Published: August 2007

The authors report about the x-ray investigation of InAs∕GaAs(001) quantum dot systems grown with varying amount of deposited InAs. It is shown that the intermixing induced composition of investigated quantum dots remains constant within the whole probed InAs deposition region. It is found that the increase of deposited InAs entirely leads to a proportional increase of surface density of dots and does not significantly influence the dot size. The dot average chemical composition was quantitatively estimated by comparison to finite-element based calculations.
Electric-current-driven vortex-core reversal in soft magnetic nanodots
Authors: Kim Sang-Koog , Choi Youn-Seok , Lee Ki-Suk , Guslienko Konstantin Y. , Jeong Dae-Eun
Published: August 2007

The authors report on electric-current-driven vortex-core (VC) reversal (switching) and the accompanying spin-wave emission, driven by spin-polarized ac currents of different amplitudes and frequencies, investigated by micromagnetic calculations of the dynamic evolution of a magnetic vortex in Permalloy nanodots. The magnetization orientation of the VC is effectively switchable between its upward and downward bistates and controllable by applying current above its threshold density, but with sufficiently small magnitude at frequencies close to the vortex eigenfrequency. This VC reversal phenomenon occurs through the creation of a vortex-antivortex pair and the subsequent annihilation of the initial vortex and the created antivortex, when the velocity of the initial VC reaches its critical value of approximately 340±20m∕s for the given material and geometry. In the course of these serial processes and immediately after VC switching, strong spin waves are emitted. These results provide physical insights into how and when current-driven VC switching takes place, thereby offering a means to manipulate bistate VC orientations.
Stress-induced birefringence in siloxane polymer waveguides
Authors: Hegde Shashikant G. , Sitaraman Suresh K.
Published: August 2007

With the increasing use of siloxane polymers as optical waveguide material, there is a need to understand and thus to reduce the stress-induced birefringence in siloxane polymer due to thermal processing and material property mismatch. In this letter, stress-optical coefficients of a siloxane polymer material are experimentally determined by measuring the refractive indices of the uncured and cured siloxane polymer material in two orthogonal directions. Employing such coefficients and temperature- and direction-dependent material properties, a numerical modeling method is presented to determine the stress-induced birefringence in an optical waveguide system. In the case study that is presented in this work, it is seen that the coefficient of thermal expansion of the planarization layer has the maximum effect on the birefringence, and it is possible to reduce the stress-induced birefringence by reducing the property mismatch between the planarization layer and the core layer. The outlined methodology is generic in nature and can be applied to different waveguide geometries, planarization materials, and substrate/board materials to assess how stress-induced birefringence can be minimized for a given polymer core material.
Observation of hexagonal nuclei in the once melt-quenched Ge2Sb2Te5 phase change contact dimensions
Authors: Youm Min Soo , Kim Yong Tae , Sung Man Young
Published: August 2007

The microstructures of once melt-quenched Ge2Sb2Te5 (GST) phase change contact dimensions are directly investigated with high resolution transmission electron microscopy (HR-TEM) by applying reset pulse of 7–13V. The ovonic threshold switching voltage is decreased from 4.1to2.8V when the as-deposited GST cells are once melt quenched by 10V. HR-TEM reveals that there are hexagonal nuclei in the once melt-quenched GST and the GST can be partially left in not the amorphous but the crystalline state when the molten GST is not swiftly quenched, which is an origin of the switching failure.
Investigation of frequency dependent and independent dielectric maxima in relaxor ferroelectric thin films
Authors: Correa Margarita , Kumar Ashok , Katiyar R. S.
Published: August 2007

Highly oriented Pb(Sc0.5Nb0.25Ta0.25)O3 (PSNT) thin films were prepared by pulsed laser deposition. The transmission electron microscopy studies showed an epitaxial strain between the layers due to the in-plane oriented heterostructure. PSNT showed a decrease in the frequency dependent dielectric maximum temperature (Tm) compared to the bulk and a frequency independent dielectric maximum at 520K around the Burns temperature (Td). The linear fit of the modified Curie-Wiess law at Tm provides γ∼2 and Δ=90K, indicating diffuse phase transition and strong relaxor behavior, further supported by nonlinear fitting of Vogel-Fulcher law. Well-behaved hysteresis loops indicated ferroelectric relaxor nature of the PSNT thin films.
Widely tunable parametric amplifier based on a superconducting quantum interference device array resonator
Authors: Castellanos-Beltran M. A. , Lehnert K. W.
Published: August 2007

The authors create a Josephson parametric amplifier from a transmission line resonator whose inner conductor is made from a series of superconducting quantum interference device (SQUID) array. By changing the magnetic flux through the SQUID loops, they are able to adjust the circuit’s resonance frequency and the center of the amplified band between 4 and 7.8GHz. They observe that the amplifier has gains as large as 28dB and infers that it adds less than twice the input vacuum noise.
Soluble misfolded subfractions of mutant superoxide dismutase-1s are enriched in spinal cords throughout life in murine ALS models
Authors: Zetterström Per , Stewart Heather G. , Bergemalm Daniel , Jonsson P. Andreas , Graffmo Karin S. , Andersen Peter M. , Brännström Thomas , Oliveberg Mikael , Marklund Stefan L.
Published: August 2007

Mutants of superoxide dismutase-1 (SOD1) cause ALS by an unidentified cytotoxic mechanism. We have previously shown that the stable SOD1 mutants D90A and G93A are abundant and show the highest levels in liver and kidney in transgenic murine ALS models, whereas the unstable G85R and G127X mutants are scarce but enriched in the CNS. These data indicated that minute amounts of misfolded SOD1 enriched in the motor areas might exert the ALS-causing cytotoxicity. A hydrophobic interaction chromatography (HIC) protocol was developed with the aim to determine the abundance of soluble misfolded SOD1 in tissues
in vivo
. Most G85R and G127X mutant SOD1s bound in the assay, but only minute subfractions of the D90A and G93A mutants. The absolute levels of HIC-binding SOD1 were, however, similar and broadly inversely related to lifespans in the models. They were generally enriched in the susceptible spinal cord. The HIC-binding SOD1 was composed of disulfide-reduced subunits lacking metal ions and also subunits that apparently carried nonnative intrasubunit disulfide bonds. The levels were high from birth until death and were comparable to the amounts of SOD1 that become sequestered in aggregates in the terminal stage. The HIC-binding SOD1 species ranged from monomeric to trimeric in size. These species form a least common denominator amongst SOD1 mutants with widely different molecular characteristics and might be involved in the cytotoxicity that causes ALS.
Cytochrome
c
oxidase deficiency in neurons decreases both oxidative stress and amyloid formation in a mouse model of Alzheimer's disease
Authors: Fukui Hirokazu , Diaz Francisca , Garcia Sofia , Moraes Carlos T.
Published: August 2007

Defects in the mitochondrial cytochrome
c
oxidase (COX) have been associated with Alzheimer's Disease, in which the age-dependent accumulation of β-amyloid plays an important role in synaptic dysfunction and neurodegeneration. To test the possibility that age-dependent decline in the mitochondrial respiratory function, especially COX activity, may participate in the formation and accumulation of β-amyloid, we generated mice expressing mutant amyloid precursor protein and mutant presenilin 1 in a neuron-specific COX-deficient background. A neuron-specific COX-deficient mouse was generated by the Cre-loxP system, in which the
COX10
gene was deleted by a CamKIIα promoter-driven Cre-recombinase. COX10 is a farnesyltransferase involved in the biosynthesis of heme
a
, required for COX assembly and function. These KO mice showed an age-dependent COX deficiency in the cerebral cortex and hippocampus. Surprisingly,
COX10
KO mice exhibited significantly fewer amyloid plaques in their brains compared with the COX-competent transgenic mice. This reduction in amyloid plaques in the KO mouse was accompanied by a reduction in Aβ42 level, β-secretase activity, and oxidative damage. Likewise, production of reactive oxygen species from cells with partial COX activity was not elevated. Collectively, our results suggest that, contrary to previous models, a defect in neuronal COX does not increase oxidative damage nor predispose for the formation of amyloidgenic amyloid precursor protein fragments.
Microfluidic system for on-chip high-throughput whole-animal sorting and screening at subcellular resolution
Authors: Rohde Christopher B. , Zeng Fei , Gonzalez-Rubio Ricardo , Angel Matthew , Yanik Mehmet Fatih
Published: August 2007

We report a suite of key microfluidic devices for complex high-throughput whole-animal genetic and drug screens. We demonstrate a high-speed microfluidic sorter that can isolate and immobilize
Caenorhabditis elegans
in a well defined geometry for screening phenotypic features at subcellular resolution in physiologically active animals. We show an integrated chip containing individually addressable screening-chamber devices for incubation and exposure of individual animals to biochemical compounds and high-resolution time-lapse imaging of many animals on a single chip without the need for anesthesia. We describe a design for delivery of compound libraries in standard multiwell plates to microfluidic devices and also for rapid dispensing of screened animals into multiwell plates. When used in various combinations, these devices will facilitate a variety of high-throughput assays using whole animals, including mutagenesis and RNAi and drug screens at subcellular resolution, as well as high-throughput high-precision manipulations such as femtosecond laser microsurgery for large-scale
in vivo
neural degeneration and regeneration studies.
Serum markers of macrophage activation in pre‐eclampsia: no predictive value of soluble CD163 and neopterin
Authors: KRONBORG CAMILLA S. , KNUDSEN ULLA BRETH , MOESTRUP SØREN K. , ALLEN JIM , VITTINGHUS ERIK , MØLLER HOLGER J.
Published: August 2007

Background. Alternatively activated macrophages expressing the CD163 and CD206 surface receptors are the dominant immune‐cell type found in the placenta. The placental number and distribution of macrophages is altered in pre‐eclampsia, and the generalised inflammatory reaction associated with pre‐eclampsia might lead to shedding of soluble CD163 into the circulation. Methods. Serum samples from 18 women with pre‐eclampsia and 90 normal pregnancies were obtained from a longitudinal study of 955 pregnant women at Randers County Hospital, Denmark. sCD163 and Neopterin were measured by ELISA on samples collected in weeks 18, 28, 32, and 38 of pregnancy. Results. sCD163 levels in pregnancy (2–3 mg/l) were similar to previously measured levels in non‐pregnant women, and did not increase from week 18 to 38. There was a tendency towards higher sCD163 in week 38 in pre‐eclamptic women compared to healthy women. Neopterin increased throughout pregnancy in both healthy (from median 5.4 to 6.7 nmol/l, p<0.0001) and pre‐eclamptic women (from 5.0 to 8.0 nmol/l, p<0.0001), but there were no differences between groups at any time‐point. sCD163 correlated to neopterin in both the control (r = 0.25, p<0.0001) and in the pre‐eclampsia group (r = 0.32, p = 0.011). C‐reactive protein was higher in pre‐eclampsia than in healthy pregnancies by week 38 (159 versus 91 nmol/l, p = 0.0189). Conclusions. The macrophage serum‐markers sCD163 and neopterin are not pre‐symptomatic nor prognostic markers for pre‐eclampsia.
Transduction patterns and efficiencies in rabbit uterine tissues after intraluminal uterine adenovirus administration vary with the reproductive cycle
Authors: LAUREMA ANNIINA , LUMME SATU , HEINONEN SUVI E. , HEINONEN SEPPO , YLÄ‐HERTTUALA SEPPO
Published: August 2007

Background. The options for destroying the full thickness of endometrium are very limited, relying mainly on surgical endometrial ablation. A nonsurgical, safe method would benefit many women in clinical settings. This study was undertaken to investigate the potential of gene therapy to transfect and destroy endometriun at different stages of the reproductive cycle in rabbits. Methods. We used adenoviruses carrying the LacZ (AdvLacZ) marker gene, indicating the transfection efficiency, and adenoviruses carrying thymidine kinase (AdvTK) followed by intravenous ganciclovir therapy as a potential treatment for excess endometrial growth. Ganciclovir was given intravenously after AdvTK treatment. Adenoviruses were injected intraluminally into the uterus of nonpregnant, pseudopregnant, and pregnant New Zealand White rabbits (n = 25). Results. After AdvLacZ gene transfer into the uterus of intact rabbits, transduced cells were observed in uterine muscle and endometrial stroma. In pseudopregnant and pregnant rabbits the endometrium was proliferative and transduction was restricted to endometrial epithelium. However, no treatment effect was observed after AdvTK gene therapy although the transduction with AdvLacZ was clearly detectable. Conclusions. It is concluded that the transduction pattern of uterine tissues varies significantly with the reproductive cycle. Secondly, although the transduction efficiency was relatively high in the endometrial epithelium, the effect of the AdvTK and ganciclovir treatment was poor and not sufficient for clinical applications.
Comparative study of conservative and surgical management for symptomatic moderate and severe hydronephrosis in pregnancy: a prospective randomized study
Authors: TSAI YIEH‐LOONG , TSAI YIEH‐LOONG , SEOW KOK‐MIN , YIEH CHUNG‐HSIN , CHONG KIAN‐MEI , HWANG JIANN‐LOUNG , LIN YU‐HUNG , HUANG LEE‐WEN
Published: August 2007

Background. To analyze the role of different measures in the treatment of acute moderate or severe symptomatic hydronephrosis in pregnancy. Methods. Of the 18,130 women delivering at our institution between January 2000 and December 2004, 93 patients were admitted due to symptomatic hydronephrosis. Among these, 50 patients were diagnosed with moderate or severe hydronephrosis, and were randomly treated with conservative measures (25 patients) or double pigtail stent insertion (25 patients). Renal sonography, urinalysis, serum creatinine levels, white blood cell counts, and urine culture were done in all patients at first visit. The clinical and perinatal outcomes of the two groups were compared. Results. The incidence of symptomatic hydronephrosis in pregnancy was 0.5% in our institution (93/18,130). The majority of the moderate or severe hydronephrosis (88%) cases were diagnosed after the first trimester. There were no statistically significant differences in the fetal body weight, Apgar score, preterm labor, and hospitalization day between the two groups. Among those receiving conservative treatment, five patients (5/25, 20%) failed to respond and were subsequently treated by double pigtail stent insertion successfully, compared with the surgical group, in which all patients were successfully relieved by double pigtail stent (p = 0.018). Four patients receiving double pigtail stent insertion complained of stent discomfort and flank pain after the procedure (16%). Conclusion. Double pigtail stent insertion is effective for the treatment of moderate or severe symptomatic hydronephrosis in pregnancy, and showed a lower failure rate than the conservative treatment. However, due to the complications and discomfort with surgical treatment, conservative treatment should still be the first choice.
Association of pre‐pregnancy maternal body mass and maternal weight gain to newborn outcomes in twin pregnancies
Authors: YEH JOHN , SHELTON JAMES A.
Published: August 2007

Background. The rate of twin gestations is now about 3% of all pregnancies. The study objective was to investigate the association between twin pregnancy newborn outcomes and maternal weight. Methods. Birth certificate information of 1,342 sets of live‐born twin deliveries collected in a regional perinatal data system from a contiguous eight‐county area in upstate New York was studied. Results. The obese maternal pre‐pregnancy BMI category was correlated with an increased odds ratio of a “Type I” (both a ≥36‐week gestation and a ≥2,500‐g average twin weight) newborn outcome (adjusted OR 1.92; 95% CI: 1.43, 2.56). For total maternal weight gain, there was an increased odds ratio of having a Type I newborn outcome with >25 kg weight gain (adjusted OR 2.24; 95% CI: 1.51, 3.33). Conclusions. Based on this population‐based study, we conclude that both maternal pre‐pregnancy BMI and total maternal weight gain are associated with twin newborn outcomes.
Knowledge, attitudes and prescribing pattern of emergency contraceptives by health care workers in Kampala, Uganda
Authors: BYAMUGISHA JOSAPHAT K. , MIREMBE FLORENCE M. , FAXELID ELISABETH , GEMZELL‐DANIELSSON KRISTINA
Published: August 2007

Background. Health care workers (HCWs) play an important role in making emergency contraceptives (ECs) available to clients. They can influence accessibility positively through counselling, prescribing or advocating the use of ECs. However, in some settings, HCWs have been blamed for unfavourable attitudes and lack of accurate information. Objective. To assess the knowledge, attitudes and prescribing pattern of EC by HCWs in Kampala district, Uganda. Methods. The total number of health units at different levels of health care delivery in Kampala (894) was obtained. Probability proportional to size (PPS) technique of sampling was applied. Some 247 HCWs completed a self‐administered questionnaire on their knowledge about EC, including methods, mechanism of action, prescription of EC, sources of information, attitudes towards EC, and if and how it should be made available. Results. Of the HCWs, 80% had knowledge of ECs. However, 1 in every 4 was not sure about the time limit within which EC is effective. A total of 50% of the participants had obtained information from a physician (26.4%) or from a training school (24%). The Yuzpe regimen was the most commonly mentioned and prescribed method of EC. The HCWs attitudes to EC were generally positive, and it was suggested that the community should be informed and sensitised about EC. There was a significant difference between having had a family planning educational update or not in the last year and knowledge of EC (p = 0.005). Conclusion. Most HCWs were aware of EC, but some lacked important knowledge on its use or available methods. Recommendation. HCWs should have regular (annual) in‐service training in reproductive health issues, such as counselling on EC. This will enable them to keep up to date with the current evidence‐based recommendations in the field of contraceptive technology.
One or two day mifepristone–misoprostol interval for second trimester abortion
Authors: NILAS LISBETH , GLAVIND‐KRISTENSEN MARIANNE , VEJBORG THOMAS , KNUDSEN ULLA BRETH
Published: August 2007

Methods. A retrospective 2‐year cohort study of 127 women, with gestation between 13 and 24 weeks and a live fetus, seeking induced abortion. The aim was to compare the effect of a 1‐day and a 2‐day interval between oral mifepristone (200 mg) and vaginal misoprostol (400 μg) every 3 h. Results. The time to fetal expulsion was longer (9.8 versus 7.5 h; p<0.01) in the 1‐day than in the 2‐day group, but the median number of applications were identical and abortion occurred in 98% within 24 h in both groups The time to abortion was longer in women with a gestation of 17–22 weeks compared to women with lower gestation (10.2 versus 6.8 h; p<0.001), and longer in nulliparae than in parous women (10.0 versus 6.7 h; p<0.001). Conclusion. The combined regimen of mifepristone and misoprostol is effective in the second trimester, and the interval between the drugs can be reduced allowing individualised patient care.
Norwegian midwives and doctors have increased cesarean section rates
Authors: LEHMANN SJUR , BØRDAHL PER E. , RASMUSSEN SVEIN A. , IRGENS LORENTZ M.
Published: August 2007

Background. Increasing cesarean section (CS) rates over the last 3 decades may, in part, be explained by improved obstetric procedures, but socio‐economic factors also play a major role. Much attention has been given to professionals’ attitudes to operative delivery, and several studies have been performed to clarify the issue. The present study explored CS rates among Norwegian doctors and midwives, compared to other professionals with an education of 17–18 years (doctors) and 15–16 years (midwives). Methods. Data on mode of delivery notified to the Medical Birth Registry of Norway for 1969–1998 (n = 1,733,665) were linked with data on formal education from Statistics Norway. CS rates and crude and adjusted odds ratios (ORs) were calculated for the observation period. Results. Female doctors and midwives had higher CS rates; the crude ORs were 1.18 (95% CI: 1.12–1.28) for doctors, and 1.35 (95% CI: 1.21–1.49) for midwives. Adjusted for age and birth order, the ORs were 1.22 (95% CI: 1.12–1.33) for doctors and 1.14 (95% CI: 1.03–1.27) for midwives. Conclusion. From 1969 to 1998, Norwegian female doctors and midwives had higher CS rates than other professionals with an education of comparable duration.
Ultrastructural alterations in human decidua in miscarriages compared to normal pregnancy decidua
Authors: KARA F. , CINAR O. , ERDEMLI‐ATABENLI E. , TAVIL‐SABUNCUOGLU B. , CAN A.
Published: August 2007

Background. Pregnant endometrial stroma, an immunologically privileged site in the female reproductive system, is enriched by decidual and natural killer (NK) cells. Since the cellular microenvironment in early pregnancy from the decidual tissues of normal and miscarriage cases has gained importance, with special emphasis on cell‐to‐cell contacts, we aimed to document the plastic structure of the cellular milieu in normal and miscarriage decidua. Methods. Endometrial biopsies were obtained from women after legal curettage or women who had been treated by curettage after miscarriage. Samples were analysed in a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Results. Decidual cells possess several polyploidic protrusions on cell membranes. NK cells were distributed among decidual cells. Decidual cells were found to develop gap junctions in the interfaces between each other. Their cytoplasms were also found to possess well‐developed protein synthesising organelles. Decidual cells obtained from miscarriages showed a moderate degree of degeneration and, in between, a decreased number of junctional complexes. Mononuclear cell infiltration was found to be significantly low. Conclusion. We conclude that decidual cells during early pregnancy build a series of miniature cell‐cell contacts to assemble a proper endometrial milieu. In contrast, in miscarriage samples, those intercellular communications seem lacking, associated with an increased number of NK cells, a phenomenon which obviously alters proper implantation and leads to the induction of embryonic disgenesis and miscarriage.
The Development and Institutionalization of Romani Representation and Administration. Part 3b: From National Organizations to International Umbrellas (1945–1970)—the International Level
Authors: Klímová-Alexander Ilona
Published: August 2007

This article is the fourth in this Nationalities Papers series, following Part 1 which covered the period from the arrival of Gypsies to Europe until the mid-nineteenth century, Part 2 describing the birth of the first modern Romani organizations from the nineteenth century up until the Second World War (WWII) and Part 3a covering the first wave of expansion of Romani activism countrywide after 1945. As mentioned in Part 3a, the period between WWII and 1970 can be distinguished from the previously covered periods by the emergence of the following phenomena: (1) modern Romani political organizations at the national level, (2) their unification through international Romani umbrella organizations, (3) some limited Romani participation in non-Romani mainstream political or administrative structures, (4) an international Romani evangelical movement, (5) reconciliation between Romani political representation and the Catholic Church, (6) national institutions created by various governments to aid the administration of policies on Roma, (7) rapid growth of non-governmental organizations addressing Romani issues, and (8) some limited cooperation between Romani organizations and intergovernmental organizations.
A Siberian Challenge: Dealing with Multiethnicity in the Republic of Buryatia
Authors: Leisse Olaf , Leisse Utta-Kristin
Published: August 2007

The Republic of Buryatia, along with 12 other former Soviet states during the same year, had declared its sovereignty no later than 8 October 1990. This did not actually mean a declaration of independence. Rather, this step was taken to urge the central government to acknowledge Buryatia as a free and equal partner at the political level. Boris Yeltsin, during his time as Russian president, did much to support this claim by propagating a vision of a post-Soviet Russia as a union of free peoples with equal rights. The central government in Moscow therefore recognized the existence of relatively autonomous regions. This was also done to respond to the interests of the different ethnic groups, which became increasingly important in the political sphere.
Hemorheological Mechanisms in Alzheimer's Disease
Authors: Chang Chia‐Yu , Liang Hong‐Jen , Chow Sin‐Yu , Chen Szu‐Ming , Liu Der‐Zen
Published: August 2007

ABSTRACT

Objective: The aim of the present study was to elucidate the underlying mechanisms responsible for hemorheological abnormalities in elderly patients with Alzheimer's disease (AD).

Subjects and Methods: Twenty‐one patients with AD and twenty‐three age‐matched healthy controls (CON) were studied. We used a controlled‐shear rate rheometer generating various flow fields in vitro for simulating blood flow in vivo. The applied experimental techniques provided valid and quantitative data for the analysis of hemorheological abnormalities associated with AD. Principal blood biochemical parameters and hemorheological parameters, including blood viscosity, erythrocyte deformability, erythrocyte aggregation and oxygen transport efficiency of blood were assessed.

Results: The results show no statistically significant difference in most of the blood biochemical parameters between the AD patients and the CON, except that fibrinogen concentration and mean corpuscular cell volume level of erythrocytes (MCV) were significantly higher in the AD patients. Hemorheological parameters including blood viscosity, plasma viscosity, and blood viscoelasticity in the AD patients were considerably higher than the respective factors in the CON. Owing to the MDA levels of the AD patients being significantly higher than that of the CON, the AD patients also showed a decrease in erythrocyte deformability and an increase in blood flow resistance despite the lack of any significant difference in erythrocyte rigidity. In addition, the erythrocyte aggregation of AD patients was higher than that of the CON and reduced oxygen transport efficiency of blood was observed in the AD patients.

Conclusions: The hemorheological abnormalities found in AD patients may be explained by the parallel findings of oxidative damage on erythrocyte membranes that could result in a decrease of erythrocyte deformability. Furthermore, the oxidative stress‐induced elevation of fibrinogen concentration could lead to accelerated erythrocyte aggregation as a consequence of a rise in blood viscosity and blood viscoelasticity. Taken together, these factors may impair the oxygen transport efficiency of blood in AD patients.
An Automated Method to Control Preload by Compensation for Stress Relaxation in Spontaneously Contracting, Isometric Rat Mesenteric Lymphatics
Authors: Davis Michael J. , Lane Megan M. , Scallan Joshua P. , Gashev Anatoliy A. , Zawieja David C.
Published: August 2007

ABSTRACT

Objective: Our objective was to devise a system to automatically correct for stress relaxation of isometric rat mesenteric lymphatics (90–120 μm, ID). Stress relaxation is a particular problem in isometric studies of highly distensible vessels and is evident as a time‐dependent, secondary decline in force after an abrupt length increase. Because the phasic contraction pattern of lymphatics is exquisitely sensitive to changes in preload, stress relaxation makes stable contraction patterns difficult to achieve and analyze.

Methods: A DMT wire myograph was modified to accommodate an Inchworm piezo stack in series with a standard micrometer drive to permit automated control of vessel caliber/force. The force output of the myograph was digitized and computer algorithms were devised to servo control force by changing vessel diameter.

Results: The system was tested on passive lymphatics, passive small veins, and lymphatics exhibiting spontaneous force transients. The software was designed to temporarily disable servo control during a spontaneous force transient. For both active and passive lymphatics, stable preloads were very well maintained, indicating that the system was adequately compensating for stress relaxation.

Conclusions: The method works well with isometric rat mesenteric lymphatics without disturbing spontaneous activity. It should be applicable to arterial, venous, and lymphatic vessels (80–500 μm in diameter) isolated from other tissues and species.
Length‐Dependence of Lymphatic Phasic Contractile Activity Under Isometric and Isobaric Conditions
Authors: Zhang Rongzhen , Gashev Anatoliy A. , Zawieja David C. , Lane Megan M. , Davis Michael J.
Published: August 2007

ABSTRACT

Objective: Experiments were designed to determine if the effect of preload on the spontaneous contractile activity of rat mesenteric lymphatics would be different under isometric and isobaric conditions.

Methods: Isobaric protocols on cannulated, pressurized rat mesenteric lymphatics (∼ 120 μ m, ID) measured the effects of lumenal pressure on contraction amplitude, frequency, and rate of diameter change (dD/dt). Analogous protocols were conducted using a wire myograph to determine the effects of passive force (preload) on the characteristics of spontaneous, isometric force transients. Servo‐control systems allowed responses to ramp or step increases in preload/pressure to be tested.

Results: Under isobaric conditions, contraction amplitude was maximal at the lowest pressure tested (1 cm H2O), and progressively declined with pressure elevation to 10 cm H2O. Changes in dD/dt followed a similar pattern. In contrast, contraction frequency progressively increased with pressure. Under isometric conditions, the amplitude of spontaneous force transients was maximal at preloads of 0.3–0.4 mN, with dF/dt following a similar pattern; the average peak amplitude was ∼ 15% of the maximal active contractile force developed during agonist stimulation. The frequency of the transients increased with preload from 0.05 to 0.3 mN, and remained constant at higher preloads. The amplitude‐frequency product, an estimate of lymphatic pumping ability, reached a maximum value at 0.4 mN in isometric vessels and at 6 cm H2O in isobaric vessels.

Conclusions: Isometric and isobaric methods yielded qualitatively similar indices of spontaneous contractile activity. However, the ranges of amplitude and frequency changes were much greater under isobaric conditions (3‐ to 5‐fold) than under isometric conditions (50–80%).
Self-Assembling Systems
Authors: Humphreys Paul
Published: August 2007

Starting with the view that methodological constraints depend upon the nature of the system investigated, a tripartite division between theoretical, semitheoretical, and empirical discoveries is made. Many nanosystems can only be investigated semitheoretically or empirically, and this aspect leads to some nanophenomena being weakly emergent. Self-assembling systems are used as an example, their existence suggesting that the class of systems that is not Kim-reducible may be quite large.
Quantum Mechanics and 3N-Dimensional Space
Authors: Monton Bradley
Published: August 2007

I maintain that quantum mechanics is fundamentally about a system of N particles evolving in three-dimensional space, not the wave function evolving in 3N-dimensional space.
Chemical “Substances” That Are Not “Chemical Substances”
Authors: Earley, Sr. Joseph E.
Published: August 2007

The main scientific problems of chemical bonding were solved half a century ago, but adequate philosophical understanding of chemical combination is yet to be achieved. Chemists routinely use important terms (“element,” “atom,” “molecule,” “substance”) with more than one meaning. This can lead to misunderstandings. Eliminativists claim that what seems to be a baseball breaking a window is merely the action of “atoms, acting in concert.” They argue that statues, baseballs, and similar macroscopic things “do not exist.” When macroscopic objects like baseballs move, exceedingly large numbers (∼1025) of microscopic components coordinate their activities. Understanding how this happens requires attention to the interactions that link parts into larger units. Eliminativists say that everything that truly exists has causal relationships in addition to those of its components—“nonredundant causality.” This paper holds that if a number of entities interact in such a way that the effect of that collection on test objects is different than it would have been in the absence of the interaction, then identification of that collection as a single composite agent is warranted, for purposes to which that difference is relevant. Ordinary “chemical substances” (both elementary materials such as dihydrogen and compounds such as water) fulfill this version of the requirement of nonredundant causality. Other sorts of chemical coherences, including chemical dissipative structures (e.g., flames), also fulfill that criterion. All these types of coherences qualify as “substances” (as that term is used in philosophy) even though they are not all “chemical substances.”
Elements, Compounds, and Other Chemical Kinds
Authors: Hendry Robin Findlay
Published: August 2007

In this article I assess the problems and prospects of a microstructural approach to chemical substances. Saul Kripke and Hilary Putnam famously claimed that to be gold is to have atomic number 79 and to be water is to be H2O. I relate the first claim to the concept of element in the history of chemistry, arguing that the reference of element names is determined by atomic number. Compounds are more difficult: water is so complex and heterogeneous at the molecular level that `water is H2O’ seems false under some interpretations. I sketch a response to this problem.
Emergence, Reduction, and Theoretical Principles: Rethinking Fundamentalism
Authors: Morrison Margaret
Published: August 2007

Many of the arguments against reductionism and fundamental theory as a method for explaining physical phenomena focus on the role of models as the appropriate vehicle for this task. While models can certainly provide us with a good deal of explanatory detail, problems arise when attempting to derive exact results from approximations. In addition, models typically fail to explain much of the stability and universality associated with critical point phenomena and phase transitions, phenomena sometimes referred to as “emergent.” The paper examines the connection between theoretical principles like spontaneous symmetry breaking and emergent phenomena and argues that new ways of thinking about emergence and fundamentalism are required in order to account for the behavior of many phenomena in condensed matter and other areas of physics.
Model-Based Reasoning in Distributed Cognitive Systems
Authors: Nersessian Nancy J.
Published: August 2007

This paper examines the nature of model-based reasoning in the interplay between theory and experiment in the context of biomedical engineering research laboratories, where problem solving involves using physical models. These “model systems” are sites of experimentation where in vitro models are used to screen, control, and simulate specific aspects of in vivo phenomena. As with all models, simulation devices are idealized representations, but they are also systems themselves, possessing engineering constraints. Drawing on research in contemporary cognitive science that construes cognition as occurring in a complex distributed system comprising people and artifacts, I argue that reasoning with model systems is a constraint satisfaction process involving co-construction, manipulation, and revision of mental and physical models.
The Role of Agency in Distributed Cognitive Systems
Authors: Giere Ronald N.
Published: August 2007

In previous publications I have argued that much scientific activity should be thought of as involving the operation of distributed cognitive systems. Since these contributions to the cognitive study of science appear in venues not necessarily frequented by philosophers of science, I begin with a brief introduction to the notion of a distributed cognitive system. I then describe what I take to be an exemplary case of a scientific distributed cognitive system, the Hubble Space Telescope (HST). I do not here reargue the case for conceiving of systems like the HST as distributed cognitive systems. Rather, I examine a question that arises once one has adopted the perspective of distributed cognitive systems, namely, the role ofagencyin a distributed cognitive system. Here I argue, contrary to several advocates of distributed cognitive systems, that we should regard the human components of distributed cognitive systems as the only sources of agency within such systems. In particular, we shouldnotextend notions of agency to such systemsas a whole.
Message in the Bottle: The Constraints of Experimentation on Model Building
Authors: Odenbaugh Jay
Published: August 2007

Some ecologists have argued that theoretical model building in population and community ecology has gone evidentially unconstrained. In the essay, I argue that “bottle experiments” offer ecological model building evidential constraints and illustrate this by considering work on chaotic models tested by the dynamics of flour beetles. Critics reply that these experiments are importantly unlike nonmanipulated natural systems and thus do not constitute genuine tests of the models. I conclude by considering two responses to this worry and a suggestion on how to move forward on this debate.
Well-Ordered Science: Evidence for Use
Authors: Cartwright Nancy
Published: August 2007

This article agrees with Philip Kitcher that we should aim for a well-ordered science, one that answers the right questions in the right ways. Crucial to this is to address questions of use: Which scientific account is right for which system in which circumstances? This is a difficult question: evidence that may support a scientific claim in one context may not support it in another. Drawing on examples in physics and other sciences, this article argues that work on the warrant of theories in philosophy of science needs to change. Emphasis should move from the warrant of theories in the abstract to questions of evidence for use.
Getting Philosophy of Science Socially Connected
Authors: Kourany Janet A.
Published: August 2007

Nearly a half century ago, Thomas Kuhn, Paul Feyerabend, Stephen Toulmin, Norwood Russell Hanson, and others issued a challenge to us philosophers of science to make our field more relevant to actual science. That challenge, over time, has elicited a number of useful responses but very few efforts to situate science within its wider social context when philosophizing about science. The unit of analysis for philosophy of science has tended to remain science-in-a-vacuum. I consider the justifications we offer for this failure, our resources for change, and our prospects if we do change.
Diachronic Coherence and Radical Probabilism
Authors: Skyrms Brian
Published: August 2007

The question ofdiachronic coherence, coherence of degrees of belief across time, is investigated within the context of Richard Jeffrey's radical probabilism. Diachronic coherence is taken as fundamental, and coherence results for degrees of belief at a single time, such as additivity, are recovered only with additional assumptions. Additivity of probabilities of probabilities is seen to be less problematic than additivity of first-order probabilities. Without any assumed model of belief change, diachronic coherence applied to higher-order degrees of belief yields the martingale property.