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Fan MHM, Wong KL, Wu S, Leung WK, Yam WC, Wong TM. Preconditioning with Porphyromonas gingivalis lipopolysaccharide may confer cardioprotection and improve recovery of the electrically induced intracellular calcium transient during ischemia and reperfusion. J Periodont Res 2009; doi: 10.1111/j.1600-0765.2009.01206.x. © 2009 John Wiley & Sons A/S Background and Objective: Porphyromonas gingivalis lipopolysaccharide (LPS) is a ligand for cell surface toll-like receptors (TLR), TLR2 and TLR4 while stimulation of either leads to cardioprotection. We hypothesized that: (1) pretreatment with P. gingivalis LPS at appropriate concentrations would induce cardioprotection against injury induced by ischemia and reperfusion; and (2) P. gingivalis LPS pretreatment at cardioprotective concentrations may reduce Ca2+ overload, which is a precipitating cause of injury, and improve recovery of contractile function. Material and Methods: Male Sprague–Dawley rats were randomly selected to receive intraperitoneal saline or hot phenol–water-extracted P. gingivalis LPS at 0.2, 0.5, 1.0, 2.0 or 4.0 mg/kg 24 h before the experiment. The hearts were isolated and subjected to regional ischemia by coronary artery ligation followed by reperfusion. In isolated rat ventricular myocytes, the cytosolic Ca2+ level and the electrically induced intracellular calcium (E[Ca2+]i) transient, which reflects contractile function, were determined after pretreatment with a cardioprotective dose of P. gingivalis LPS. Results: Pretreatment with 0.5 mg/kg P. gingivalis LPS significantly reduced, while pretreatment with 1.0–4.0 mg/kg significantly increased infarct size. The Ca2+ overload induced by ischemia–reperfusion was attenuated in myocytes from rats pretreated with 0.5 mg/kg P. gingivalis LPS. Pretreated myocytes also showed an increased amplitude of the E[Ca2+]i transient, no prolongation of the time to reach the peak E[Ca2+]i transient and shorter 50% decay time during reperfusion. Conclusion: At a dosage of 0.5 mg/kg, P. gingivalis LPS confers cardioprotection against ischemia–reperfusion-induced injury and improved intracellular E[Ca2+]i transient recovery, hence improving myocyte contractile recovery.

The National Compact Stellarator Experiment (NCSX) was designed to test a compact, quasiaxisymmetric stellarator configuration. Flexibility and accurate realization of its complex 3D geometry were key requirements affecting the design and construction. While the project was terminated before completing construction, there were significant engineering accomplishments in design, fabrication, and assembly. The design of the stellarator core device was completed. All of the modular coils, toroidal field coils, and vacuum vessel sectors were fabricated. Critical assembly steps were demonstrated. Engineering advances were made in the application of CAD modeling, structural analysis, and accurate fabrication of complex-shaped components and subassemblies. The engineering accomplishments of the project are summarized

The National Compact Stellarator Experiment (NCSX) is a quasi-axisymmetric facility that combines the high beta and good confinement features of an advanced tokamak with the low current, disruption-free characteristics of a stellarator. The experiment is based on a three field-period plasma configuration with an average major radius of 1.4 m, a minor radius of 0.3 m, and a toroidal magnetic field on axis of up to 2 T. The modular coils are one set in a complex assembly of four coil systems that surround the highly shaped plasma. There are six, each of three coil types in the assembly for a total of 18 modular coils. The coils are constructed by winding copper cable onto a cast stainless steel winding form that has been machined to high accuracy, so that the current center of the winding pack is within ±1.5 mm of its theoretical position. The modular coils operate at a temperature of 80 K and are subjected to rapid heating and stress during a pulse. At this time, the project has completed construction of several prototype components which validate the fabrication and inspection processes that are planned for the production coils. In addition, some advanced techniques for error-field compensation and assembly simulation using computer-aided design (CAD) have been developed.

A detailed electromagnetic-structural ANSYS analysis of the NCSX Modular Coil (MC) system is presented. The simplified (linear) model is used to provide some insights into the essential behavior of the modular coil. In the actual device, the winding packs are Vacuum Pressure Impregnated (VPI’d) in-place and restrained by 50+ clamps per coil. In general, JxB Lorentz forces press the winding pack (WP) onto the structure which makes the linear (“glued”) approach justifiable. The benefit, of course, is relatively fast computer run-times and a modeling tool which is able to perform numerous design studies. However, there are regions where the electromagnetic (EM) forces point away from the structure and locally invalidate the glued approximation.The results of a variety of design studies are presented, such as the structural stiffness and worst case running loads at the poloidal breaks, non-ideal coil center displacements from thermal contractions and structural loads, smeared winding pack and winding ...

A non linear FEA study has been performed on the modular coils of the National Compact Stellarator Experiment (NCSX). The modular coils provide the primary magnetic field within NCSX and consist of flexible cable conductor wound on a cast and machined winding form and vacuum impregnated with epoxy. Eighteen coils and associated winding forms are connected at assembly into a toroidal shell structure. The purpose of this study was to evaluate the structural response of the windings and shell structure during cooldown and normal operation. Two separate software packages were used for the study, and two independent analyses were undertaken. The first analysis performed with Pro/Mechanica, examined both the response of the modular coils to magnetic pressure and thermal effects during a 2 Tesla pulse. Modeled items included a portion of the shell structure the winding packs, and a set of 48 'pseudo clamps'. The so called 'pseudo clamps' are represented simply by blocks of material that are restrained in their respective normal directions and have properties which mimic the stiffness of the spring washers of the actual preload clamps. The winding pack is free to slide on the shell structure and is restrained only by the clamps. A secondmore » model, including the complete shell structure of all three coils, was studied with the FEA program ANSYS. Contact regions defined in both Pro/Mechanica and Ansys allow the winding to slide and detach form the shell structure. The two analyses are compared for parameters such as winding/structure gap, overall displacement, equivalent stress and principle strain values.« less

The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, , and ) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W {center_dot} cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si{sub 3}N{sub 4}), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm {+-} 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) materialmore » properties and CAD modeling and analysis of the window design suggest that silicon may be a viable solution to inherent parameters and constraints.« less

The National Compact Stellarator Experiment (NCSX) is a quasi-axisymmetric plasma experiment that combines the high beta and good confinement of an advanced tokamak with the low current, disruption-free characteristics of a stellarator. The experiment is based on a three field-period plasma configuration with an average major radius of 1.4 m, a minor radius of 0.3 m, and a toroidal magnetic field on axis of up to 2 T. The modular coils are one set in a complex assembly of four coil systems that surround the highly shaped plasma. There are six each of three coil types in the assembly, for a total of 18 modular coils. The coils are constructed by winding copper cable onto a cast stainless steel winding form that has been machined to high accuracy, so that the current center of the winding pack is within +/-1.5 mm of its theoretical position. The modular coils operate at a temperature of 80 K and are subjected to rapid heating and stress during a pulse. The final coil design has presented many challenges with its requirements for winding accuracy, good thermal performance, a robust supporting structure, and ease of assembly and maintenance

Optical switches based on liquid crystal SLM (Spatial Light Modulators) have traditionally been considered unsuitable for packet switching due to slow reconfiguration speed. In this paper we investigate the constraint of reconfiguration time in an optically interconnected packet switch. A system architecture based on the established knockout principle and input/output buffers is simulated with self-similar traffic patterns and packet length statistics obtained from NLANR. Analysis includes packet delay distribution, queue length growth. A physical realisation of the system will use VCSEL arrays, detector arrays and multi-mode ribbon fibre. Data granularity of the system is chosen to match the specification of modern line cards used in routers. It is found that a reconfiguration time in the order of micro seconds is sufficient for an acceptable delay and loss rate. Relationships between required reconfiguration time and system parameters are established.

The design status of the stellarator core for the National Compact Stellarator Experiment (NCSX) is presented. The purpose, configuration, and possible manufacturing and assembly techniques of the various components of the core are described.

The National Compact Stellarator Experiment (NCSX) is proposed as a test of a low aspect ratio, quasi-axisymmetric plasma configuration that exhibits high beta and good confinement in a disruption-free environment. The experiment will be built at Princeton Plasma Physics Laboratory (PPPL) and utilize some ancillary equipment. The NCSX stellarator core is a complex assembly of four coil systems which provide the magnetic field for plasma shaping and position control, inductive current drive, and field error correction. The primary magnets are the modular coils, which provide up to 2-T at an average major radius of 1.4-m. Other magnets include toroidal field (TF) coils, poloidal field (PF) coils, and trim coils, which can be used to control resonant field errors. The magnets are supported by an integral shell structure, which also serves as the winding form for the modular coils. The coils and structure have been evaluated for thermal stress and electromagnetic loads during normal operating conditions. The results indicate that the performance of the modular coil system is acceptable.

The National Spherical Tokamak Experiment (NSTX) is an ultra low aspect ratio (R/a=1.25; R=80 cm) device designed for a plasma current of 1 MA. It features auxiliary heating and current drive and a close-fitting conducting shell to maximize plasma pressure (43% beta). NSTX is designed for a 5 sec. experimental pulse to demonstrate quasi-steady state non-inductively driven advanced tokamak operation. The design takes maximum advantage of existing components and facilities from previous devices at PPPL to reduce the program costs. The device will be sited in the former Princeton Large Torus (PLT) test cell and will utilize the PLT radiation shielding, base structure, and cell utilities. NSTX will utilize the S-1 Spheromak vacuum vessel, poloidal field coils, and capacitor banks (for helicity injection). The Poloidal Beta Experiment-Modified (PBX-M) power supplies will be shared to power the PF and TF coil systems. Existing RF hardware and infrastructure will be used for heating systems. TFTR data acquisition and diagnostics resources are planned to be used. In total, NSTX will utilize site credits with a value of /spl sim/$50 M, reducing base construction cost of the device to $18.6 M. Twelve water-cooled copper demountable toroidal field (TF) coils provide the 5.4 kg (pulsed) and 3.5 kg (long pulse >5 sec) toroidal field at the plasma center. Poloidal fields are generated by windings contained in the center column and four pairs water-cooled copper coils supported directly on the vacuum vessel. One of the most critical components of the device is the center stack, which consists of the inner legs of the TF coils overwrapped with ohmic heating and poloidal field windings. The ohmic heating coil windings are designed to optimize the V-s and together with the PF coils, produce a flux swing of 1 V-s.

The National Spherical Tokamak Experiment is a low-aspect-ratio tokamak facility currently in the conceptual design phase. The vacuum vessel, in addition to provides a high vacuum chamber for plasma experiments, also serves as a load-carrying element for supporting the center stack, the external poloidal field coils, and the toroidal field coils. Design requirements and structural considerations for the vacuum vessel and its support structure were described in the paper. Structural responses were calculated using the finite element method. Various loading conditions including in the analyses are dead weight, static electromagnetic loads, plasma disruptions, bakeout thermal effects, vacuum pressure, seismic excitations, and simultaneously occurrence of such loadings.

An evolutionary process was used to develop the toroidal field (TF) coil design for the ARIES-ST (Spherical Tokamak). Design considerations included fabricability, assembly, maintenance, energy efficiency, and structural robustness. The design addresses a number of the concerns (complexity) and criticisms (high cost, high recirculating power) of fusion. It does this by: (1) Applying advanced, but available laser forming and spray casting techniques for manufacturing the TF coil system; (2) Adopting a simple single toroidal field coil system to make assembly and maintenance much easier, the single turn design avoids the necessity of using the insulation as a structural component of the TF coils, and hence is much more robust than multi-turn designs; and (3) Using a high conductivity copper alloy and modest current densities to keep the recirculating power modest.

NSTX is one of the largest of a new class of magnetic plasma research devices known as spherical toroids (STs). The plasma in a ST is characterized by its almost spherical shape with a slender cylindrical region through its vertical axis. The so-called ''center stack'' is located in this region. It contains magnetic windings for confining the plasma, induce the plasma current, and shape the plasma. This paper will describe the engineering challenges of designing the center stack magnets to meet their operational requirements within this constrained space.

CdSxSe1−x nanobelts with uniform and controllable composition are successfully fabricated by a one-step vapor-liquid-solid process. Temperature-dependent steady and time-resolved transient photoluminescence (PL) are studied for the obtained CdSxSe1−x nanobelts as well as pure CdS and CdSe nanobelts prepared in same method. For all samples, both band edge and surface state emission are found to contribute to the observed PL spectra. However, the emission originated from surface state is quite weak for CdSxSe1−x nanobelts as compared to CdS and CdSe. The reduced surface state emission in CdSxSe1−x nanobelts is ascribed to exciton localization due to random potential fluctuations. This attribution is further confirmed by the time-decay PL profiles where a very fast process of exciton transfer from interior to surface of nanobelts, observed in CdS and CdSe nanobelts, is absent for CdSxSe1−x nanobelts. These observations reveal that the surface effect of CdSxSe1−x nanobelts is less significant than that in CdS...

Intrauterine devices (IUDs) are widely used in China for contraception, but uterine bleeding is the most common side effect. This study is to observe the effects on menstrual blood loss (MBL) of the 4 types of IUDs —stainless steel ring (SR), Shanghai copper T 200 (CuT), Shanghai copper V 200 (CuV) and Beijing copper V 200 (BV) —which are commonly used in China. MBL was determined in 82 subjects in pre and postinsertion periods. After insertion, the mean MBL of all types of IUDs were significantly higher than that before insertion (P