Immune system involvement in the regulation of ovarian function and augmentation of cancer

Increasing evidence indicates a role for the immune system and mesenchymal-epithelial interactions in the regulation of ovarian function. Cytokines produced by mesenchymal cells can stimulate development and regression of ovarian structures. We report here that mesenchymal cells releasing surface molecules among epithelial cells--namely vascular pericytes and monocyte-derived cells (MDC)--and intraepithelial T lymphocytes are associated with oogenesis and formation of new primary follicles in both fetal and adult human ovaries. These activated mesenchymal cells interact with the ovarian surface epithelium, which appears to be a source of secondary germ cells and granulosa cells. Activated pericytes and MDC are also associated with stimulation of thecal development during selection of growing secondary follicles from the cohort of primary follicles. However, survival of the dominant follicle during mid-follicular phase selection is associated with a lack of activity of mesenchymal cells and retardation of thecal development, since immature granulosa cells lacking aromatase are unable to resist high levels of thecal androgens. Once the selected follicle matures (late follicular phase), it shows enhanced activity of thecal mesenchymal cells and advanced thecal development. Corpus luteum (CL) development is accompanied by a high activity of vascular pericytes and MDC. In mature CL and CL of pregnancy, luteal MDC and pericytes show a stable (inactive) state. Regression of the CL is associated with regression of pericytes, transformation of MDC into dendritic cells, infiltration by T lymphocytes, and binding of immunoglobulin G to the luteal cells. The immunoglobulin M (IgM) binds to young but not mature luteal cells. In the CL of pregnancy, IgM binds to luteal vessels, but not to luteal cells. Regressing CL shows IgM binding to both luteal cells and vessels. In ovarian cancers, highly activated MDC and sometimes activated pericytes (poorly differentiated carcinomas) are present. IgM binding is similar to that seen in the CL of pregnancy. These data indicate that vascular pericytes, MDC, T cells, and immunoglobulins may play an important role in the regulation of ovarian physiology and contribute to the augmentation of ovarian cancer growth.     

Preface: Volume 68, Issue 6

INFINITY 2002, the 4th International Workshop on Verification of Infinite-State Systems, was held as a satellite workshop of CONCUR 2002 (the 13th International Conference on Concurrency Theory) in Brno, Czech Republic, on August 24, 2002. The aim of the workshop is to provide a forum for researchers interested in the development of mathematical techniques for the analysis and verification of systems with infinitely many states. The topics of INFINITY 2002 included the following: techniques for modeling and analysis of infinite-state systems, equivalence-checking and model-checking with infinite-state systems, parameterized systems, calculi for mobility and security, finite-state abstractions of infinite-state systems.The volume consists of six contributed papers selected by the INFINITY 2002 programme committee. The papers were reviewed by the program committee consisting, besides editors, of

Parosh Abdulla	(Uppsala (SE))
Julian Bradfield	(Edinburgh (UK))
Didier Caucal	(Irisa (F))
Hubert Comon	(LSV Cachan (F))
Giorgio Delzanno	(Genova (I))
Yoram Hirshfeld	(Tel-Aviv (Israel))
Denis Lugiez	(Marseille (F))
Bernhard Steffen	(Dortmund (D))
P.S. Thiagarajan	(Chennai (India))
Moshe Vardi	(Rice (USA))

Full-size table

The programme of INFINITY 2002 was further enriched by an invited talk given by Colin Stirling, and by four short presentations of work in progress.This volume will be published as volume 68(6) in the series Electronic Notes in Theoretical Computer Science (ENTCS). This series is published electronically through the facilities of Elsevier Science B.V. and its auspices. The volumes in the ENTCS series can be accessed at the URL http://www.elsevier.nl/locate/entcsWe are very grateful to the CONCUR 2002 Organizing Committee for arranging all local affairs, and to Michael Mislove, the managing editor of ENTCS, for providing the opportunity to publish the INFINITY 2002 proceedings in the ENTCS series.December 9, 2002 Antonin Kucera, Richard Mayr     

On the presence of work-hardened zones around fibers in a short-fiber-reinforced Al metal matrix composite

Dislocation densities are investigated in a short-fiber-reinforced Al–11 wt.% Zn–0.2 wt.% Mg metal matrix composite (MMC) with a special focus on regions near the fiber–matrix interfaces. Clear microstructural evidence is provided for the formation of work-hardened zones (WHZs) around fibers during creep using transmission electron microscopy (TEM). The dislocation densities in the WHZs are higher after creep than after squeeze casting, where the plastic strains associated with the thermal stresses that build up during solidification also result in an increased dislocation density close to fibers. The effect of heating and cooling on the dislocation substructure is also considered. The results are discussed in light of previous findings and provide microstructural evidence for the presence of WHZs as predicted by the Dlouhy model of MMC creep.     

Analysis of local microstructure after shear creep deformation of a fine-grained duplex γ-TiAl alloy

The present work characterizes the microstructure of a hot-extruded Ti–45Al–5Nb–0.2B–0.2C (at.%) alloy with a fine-grained duplex microstructure after shear creep deformation (temperature 1023 K; shear stress 175 MPa; shear deformation 20%). Diffraction contrast transmission electron microscopy (TEM) was performed to identify ordinary dislocations, superdislocations and twins. The microstructure observed in TEM is interpreted taking into account the contribution of the applied stress and coherency stresses to the overall local stress state. Two specific locations in the lamellar part of the microstructure were analyzed, where either twins or superdislocations provided c-component deformation in the L1₀ lattice of the γ phase. Lamellar γ grains can be in soft and hard orientations with respect to the resolved shear stress provided by the external load. The presence of twins can be rationalized by the superposition of the applied stress and local coherency stresses. The presence of superdislocations in hard γ grains represents indirect evidence for additional contributions to the local stress state associated with stress redistribution during creep.     

Bimodal model for predicting the emulsion-hydrate mixture viscosity in high water cut systems

For many production operations, particularly deepwater fields, those requiring long tiebacks, water flooded and mature reservoirs (where water cuts can be very high), the traditional techniques to prevent hydrate problem may not be economical and/or logistically practical. Thus the industry needs improved techniques to tackle flow assurance problems for such challenging conditions.Preventing hydrate agglomeration and transportation of hydrate slurry could be a new solution. The rheological behaviour of hydrate slurry has mainly been investigated in low water cut systems where water is the limiting factor. In high water cut systems, hydrate former components are the limiting factor and therefore the rheological behaviour of hydrate slurry has to be study in water–oil emulsion and this has a significant role on the viscosity of the system.In this communication, a model to predict the viscosity of water–oil emulsion in the presence of hydrate particles in high water cut systems using the concept for a bimodal mixture is proposed. In the model, water–oil emulsion and hydrate particles in the liquid continuous phase are treated separately as unimodal models. In addition, a modification has been applied to the Mills (1985) model to calculate the viscosity of unimodal hydrate suspensions. The model has been validated using experimental data for high water cut systems (above 50%) in the presence of different anti-agglomerant (AA) concentrations. The predictions of the proposed model are in good agreement with experimental data for both oil-in-water and water-in-oil hydrate mixtures.     

FRACTURE CHARACTERISTICS OF BOROSILICATE GLASSES REINFORCED BY METALLIC PARTICLES

Abstract— The fracture behaviour of borosilicate glass reinforced by molybdenum and/or vanadium particles has been investigated. For the addition of 5 vol% molybdenum particles, two processing procedures have been tested and the influence of volume fraction of vanadium particles (in the range 2 to 30 vol%) on fracture resistance has been assessed. The use of chevron-notched specimens in three-point bending has been shown to be a reliable method for the evaluation of fracture toughness even at toughness levels of order 0.7 to 1.3 MPa √m. The existence of subtle differences in fracture behaviour of glass-composites having comparable volume fractions of molybdenum particles but obtained by two different processing procedures has been established by statistical treatment of the fracture toughness data. An increase in the volume fraction of metallic particles results in an increase of the fracture resistance and the measured fracture toughness level. Toughening mechanisms which have been identified include both the plastic deformation of particles and the bridging of cracks by ductile particles. Some particle cleavage and debonding has been observed, which indicates that a decrease in particle plasticity, probably induced by processing or due to constraints imposed by the rigid matrix, is responsible for a smaller than expected enhancement of the fracture toughness.     

Giant Barocaloric Effect at the Spin Crossover Transition of a Molecular Crystal

The first experimental evidence for a giant, conventional barocaloric effect (BCE) associated with a pressure‐driven spin crossover transition near room temperature is provided. Magnetometry, neutron scattering, and calorimetry are used to explore the pressure dependence of the SCO phase transition in polycrystalline samples of protonated and partially deuterated [FeL₂][BF₄]₂ [L = 2,6‐di(pyrazol‐1‐yl)pyridine] at applied pressures of up to 120 MPa (1200 bar). The data indicate that, for a pressure change of only 0–300 bar (0–30 MPa), an adiabatic temperature change of 3 K is observed at 262 K or 257 K in the protonated and deuterated materials, respectively. This BCE is equivalent to the magnetocaloric effect (MCE) observed in gadolinium in a magnetic field change of 0–1 Tesla. The work confirms recent predictions that giant, conventional BCEs will be found in a wide range of SCO compounds.     

On the Stress-Induced Formation of R-Phase in Ultra-Fine-Grained Ni-Rich NiTi Shape Memory Alloys

Phase transformations in binary ultra-fine-grained (UFG) pseudoelastic NiTi wires were studied in a wide temperature range using mechanical loading/unloading experiments, resistance measurements, differential scanning calorimetry (DSC), thermal infrared imaging, and transmission electron microscopy (TEM). The formation of R-phase can be detected in the mechanical experiments. It is shown that the stress-strain response of the R-phase can be isolated from the overall stress-strain data. The R-phase always forms prior to B19′ when good pseudoelastic properties are observed. The stress-induced B2 to R-phase transition occurs in a homogeneous manner, contrary to the localized character of the B2/R to B19′ transformations. The temperature dependence of the critical stress values for the formation of the martensitic phases shows a Clausius Clapeyron type of behavior with constants close to 6 MPa/K (B19′) and 18 MPa/K (R-phase). A stress-temperature map is suggested that summarizes the experimentally observed sequences of elementary transformation/deformation processes.     

Selective isolation of Pseudomonas stutzeri from vertebrate faeces on Rambach agar

BACKGROUND: Patients undergoing cardiovascular surgery are at high risk for sores because of impaired perfusion, the time spent on the operating room table, and restricted mobility in the immediate postoperative period. OBJECTIVE: To identify risk factors for sores. METHODS: In a 900-bed teaching hospital, 163 patients who underwent cardiovascular interventions were enrolled. Risk measurement included skin assessment, Braden and Norton scales, physic and biologic data and specific risk factors. The development of the most severe stages of pressure sores was followed (Stages II and III). RESULTS: Forty-eight (29.5%) patients totalized 75 pressure sores. In univariate analyses, Norton and Braden scores, hemoglobin concentration, presence of ulcers at admission, use of antihypertensive drugs, systemic use of corticosteroids, nosocomial infection, re-intervention and readmission in intensive care units were associated with sores. In a logistic regression model, hemoglobin concentration at admission (p=0.0007), postoperative Braden score (p=0.0002), and postoperative steroid therapy (p=0.020) were the only predictors of sores. Total length of stay was 6 days higher (p=0.03) for patients with pressure sores. CONCLUSIONS: The detection of risks is recommended during the entire stay. Identification of patients at risk is required to provide preventive resources appropriately, which can lessen the incidence of pressure sores and reduce patient discomfort, length and costs of hospital stay.