PHENIX magnet system Aronson, S.H.; Bowers, J.; Chiba, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
The PHENIX magnet system is composed of three spectrometer magnets with warm iron yokes and water-cooled copper coils. The Central Magnet (CM) is energized by two pairs of concentric coils and ...provides a field around the interaction vertex that is parallel to the beam. This allows momentum analysis of charged particles in the polar angle range from 70° to 110°. The north and south Muon Magnets (MMN and MMS) use solenoid coils to produce a radial magnetic field for muon analysis. They each cover a pseudorapidity interval of 1.1–2.3 and full azimuth. The coils are wound on cylindrical surfaces at the end of large tapered pistons. Each of the three magnets provides a field integral of about
0.8
T
-m. The physical and operating parameters of the magnets and their coils are given along with a description of the magnetic fields generated. The geometric, thermal and magnetic analysis leading to the coil design is discussed. The magnetic volumes of the PHENIX magnets are very large and complex, so a new technique was developed to map the fields based on surface measurements of a single field component using single axis Hall probes mounted on a rotating frame. A discussion of the performance of the CM during the first year of PHENIX running is given.
The PHENIX Photon Electron New Heavy Ion Experiment Detector is one of two large detectors presently under construction for RHIC (Relativistic Heavy Ion Collider) located at Brookhaven National ...Laboratory. Its primary goal is to detect a new phase of matter; the quark-gluon plasma. In order to achieve this objective, the PHENIX Detector utilizes a complex magnet subsystem which is comprised of two large magnets identified as the Central Magnet and the Muon Magnet. Muon Identifier steel is also included as part of this package. The entire magnet subsystem stands over 10 meters tall and weighs in excess of 1900 tons. Magnet size alone provided many technical challenges throughout the design and fabrication of the project. In addition, interaction with foreign collaborators provided the authors with new areas to address and problems to solve. Russian collaborators would fabricate a large fraction of the steel required and Japanese collaborators would supply the first coil. This paper describes the overall design of the PHENIX magnet subsystem and discusses its present fabrication status.
BACKGROUND Female cancer patients are offered ‘banking’ of gametes before starting fertility-threatening cancer therapy. Transplants of fresh and frozen ovarian tissue between healthy fertile and ...infertile women have demonstrated the utility of the tissue banked for restoration of endocrine and fertility function. Additional methods, like follicle culture and isolated follicle transplantation, are in development. METHODS Specialist reproductive medicine scientists and clinicians with complementary expertise in ovarian tissue culture and transplantation presented relevant published literature in their field of expertise and also unpublished promising data for discussion. As the major aims were to identify the current gaps prohibiting advancement, to share technical experience and to orient new research, contributors were allowed to provide their opinioned expert views on future research. RESULTS Normal healthy children have been born in cancer survivors after orthotopic transplantation of their cryopreserved ovarian tissue. Longevity of the graft might be optimized by using new vitrification techniques and by promoting rapid revascularization of the graft. For the in vitro culture of follicles, a successive battery of culture methods including the use of defined media, growth factors and three-dimensional extracellular matrix support might overcome growth arrest of the follicles. Molecular methods and immunoassay can evaluate stage of maturation and guide adequate differentiation. Large animals, including non-human primates, are essential working models. CONCLUSIONS Experiments on ovarian tissue from non-human primate models and from consenting fertile and infertile patients benefit from a multidisciplinary approach. The new discipline of oncofertility requires professionalization, multidisciplinarity and mobilization of funding for basic and translational research.
The extracellular matrix (ECM) provides a three-dimensional structure that promotes and regulates cell adhesion and provides signals that direct the cellular processes leading to tissue development. ...In this report, synthetic matrices that present defined ECM components were employed to investigate these signaling effects on tissue formation using ovarian follicle maturation as a model system. In vitro systems for follicle culture are being developed to preserve fertility for women, and cultures were performed to test the hypothesis that the ECM regulates follicle maturation in a manner that is dependent on both the ECM identity and the stage of follicle development. Immature mouse follicles were cultured within alginate-based matrices that were modified with specific ECM components (e.g., laminin) or RGD peptides. The matrix maintains the in vivo like morphology of the follicle and provides an environment that supports follicle development. The ECM components signal the somatic cells of the follicle, affecting their growth and differentiation, and unexpectedly also affect the meiotic competence of the oocyte. These effects depend upon both the identity of the ECM components and the initial stage of the follicle, indicating that the ECM is a dynamic regulator of follicle development. The development of synthetic matrices that promote follicle maturation to produce meiotically competent oocytes may provide a mechanism to preserve fertility, or more generally, provide design principles for scaffold-based approaches to tissue engineering.
The developmental requirements of ovarian follicles are dependent on the maturation stage of the follicle; in particular,
elegant studies with genetic models have indicated that FSH is required for ...antral, but not preantral, follicle growth and
maturation. To elucidate further the role of FSH and other regulatory molecules in preantral follicle development, in vitro
culture systems are needed. We employed a biomaterials-based approach to follicle culture, in which follicles were encapsulated
within matrices that were tailored to the specific developmental needs of the follicle. This three-dimensional system was
used to examine the impact of increasing doses of FSH on follicle development for two-layered secondary (100â130 μm; two layers
of granulosa cells surrounding the oocyte) and multilayered secondary (150â180 μm, several layers of granulosa cells surrounding
the oocyte) follicles isolated from mice. Two-layered secondary follicles were FSH responsive when cultured in alginate-collagen
I matrices, exhibiting FSH dose-dependent increases in follicle growth, lactate production, and steroid secretion. Multilayered
secondary follicles were FSH dependent, with follicle survival, growth, steroid secretion, metabolism, and oocyte maturation
all regulated by FSH. However, doses greater than 25 mIU/ml of FSH negatively impacted multilayered secondary follicle development
(reduced follicle survival). The present results indicate that the hormonal and environmental needs of the follicular complex
change during the maturation process. The culture system can be adapted to each stage of development, which will be especially
critical for translation to human follicles that have a longer developmental period.
Abstract
Two-layered secondary follicles were FSH responsive, and multilayered secondary follicles were FSH dependent, when cultured
in a three-dimensional alginate culture system; FSH dose regulated follicle growth, steroid secretion, and oocyte maturation
Identification of a G protein-coupled receptor activated by UDP-glucose led us to develop a sensitive and specific assay for UDP-glucose mass and to test whether this sugar nucleotide is released as ...an extracellular signaling molecule. Mechanical stimulation of 1321N1 human astrocytoma cells by a change of medium resulted in an increase in extracellular levels of both ATP and UDP-glucose. Whereas ATP levels peaked within 10 min and subsequently returned to resting extracellular levels of 3 nM, UDP-glucose levels attained a steady state that exceeded that of resting ATP levels by 3- to 5-fold for at least 3 h. Similar rates of basal release of UDP-glucose and ATP (72 and 81 fmol/min/10(6) cells) combined with a rate of UDP-glucose metabolism approximately three times lower than ATP hydrolysis account for the elevated extracellular UDP-glucose levels on resting cells. A medium change also resulted in rapid appearance of UDP-glucose on the luminal surface of highly differentiated polarized human airway epithelial cells but at levels 2- to 3-fold lower than ATP. However, nucleotide sugar levels increased 3- to 5-fold over the ensuing 2 h, whereas ATP levels decayed to a resting level; consequently, resting extracellular UDP-glucose levels exceeded those of ATP by 5- to 10-fold. UDP-glucose also was observed at levels that equaled or exceeded those of ATP in the extracellular medium of Calu-3 airway epithelial, COS-7, CHO-K1, and C6 glioma cells. Consistent with the observation of significant extracellular UDP-glucose levels, expression of the UDP-glucose-activated P2Y(14) receptor in COS-7 cells resulted in G protein-promoted inositol phosphate accumulation that was partially reversed by enzymatic removal of UDP-glucose from the medium. Taken together, these results indicate constitutive release of UDP-glucose from physiologically relevant tissues and suggest that UDP-glucose acts as an autocrine activator of the P2Y(14) receptor. Because cellular UDP-glucose is concentrated in the lumen of the endoplasmic reticulum, we speculate that UDP-glucose release may occur as a result of vesicle transport during trafficking of glycoproteins to the plasma membrane.
Human infectious diseases have been studied in pigs because the two species have common microbial, parasitic, and zoonotic organisms, but there has been no systematic evaluation of cytokine gene ...expression in response to infectious agents in porcine species. In this study, pigs were inoculated with two clinically and economically important parasites, Toxoplasma gondii and Ascaris suum, and gene expression in 11 different tissues for 20 different swine Th1/Th2-related cytokines, cytokine receptors, and markers of immune activation were evaluated by real-time PCR. A generalized Th1-like pattern of gene expression was evident in pigs infected with T. gondii, along with an increased anti-inflammatory gene expression pattern during the recovery phase of the infection. In contrast, an elevated Th2-like pattern was expressed during the period of expulsion of A. suum fourth-stage larvae from the small intestine of pigs, along with low-level Th1-like and anti-inflammatory cytokine gene expression. Prototypical immune and physiological markers of infection were observed in bronchial alveolar lavage cells, small intestinal smooth muscle, and epithelial cells. This study validated the use of a robust quantitative gene expression assay to detect immune and inflammatory markers at multiple host tissue sites, enhanced the definition of two important swine diseases, and supported the use of swine as an experimental model for the study of immunity to infectious agents relevant to humans.
Extracellular matrix (ECM) proteins are established regulators of granulosa cell survival, morphology, and differentiation. In this study, the roles of ECM adhesion peptide density on murine ...granulosa cell adhesion, morphology, and steroid secretion were probed using synthetic matrices. The synthetic matrix was fabricated from the polysaccharide alginate, which does not inherently support cell adhesion but can be modified with controlled densities of adhesion peptides (10
−4 to 2×10
−1 ng/cm
2). GRM02, a murine granulosa cell line, and primary murine granulosa cells were cultured on alginate matrices modified by coupling of synthetic peptide sequences containing the Arg–Gly–Asp motif common to ECM proteins. Cells cultured on these peptide-modified surfaces (0.02, 0.2 ng/cm
2) attached and spread, with morphologies specific to the peptide identity and density. Additionally, progesterone and estradiol secretion was a function of peptide density, with up to threefold increases compared to controls. These results indicate that the density and identity of adhesion peptides regulate granulosa cell function. This system provides a mechanism to examine the granulosa cell-ECM interactions that occur during follicle maturation.
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