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About one hundred magnets of six different types shall be installed in the High Luminosity LHC (HL-LHC) in the years 2026-2028 at CERN. The magnets design, construction and test are based on CERN collaborations with institutes and industrial partners in USA, Spain, Italy, Japan and China. Three types of correctors are based on Nb‒Ti technology and feature conductor peak fields in the 2 to 4 T range: for all of them the prototype phase has been successfully completed. The production is well advanced for the superferric correctors, and is starting for the canted cosine theta correctors and for the nested correctors. The separation and recombination Nb‒Ti dipoles D1 and D2, with a 4.5-6 T bore field range, are both in the prototype phase after the completion of the short model program. The most challenging magnet, the Nb3Sn quadrupole with conductor peak field above 11 T, is in the prototype phase at CERN and halfway through the production phase in the USA. In this paper we will give, for each type of magnet, an overview of the main achievements obtained so far and we will outline the technical points still needing validation from the prototype program.

International audience; For the HL-LHC project, a 90 mm NbTi cos(2θ) double aperture quadrupole magnet with an operating gradient of 120 T/m at 1.9 K has been designed as an option to replace the 70 mm aperture LHC quadrupole MQY. CEA in collaboration with CERN designed and manufactured a single aperture short model magnet with a magnetic length of 1.215 m at 1.9 K called MQYYM. The MQYYM cold test occurred at CEA at 4.2 K in a vertical cryogenic station. During the power test, the operating gradient at 1.9 K has been reached after two training quenches. All along the test, magnetic and mechanical measurements were done using respectively a rotating probe and strain gauges. This paper describes the performance of the MQYYM at 4.2 K and gives an analysis of the data acquired during the test, including training behavior, quench detection, protection and field quality measurements.

The use of pressurized bladders for stress control of superconducting magnets was firstly proposed at Lawrence Berkeley National Laboratory in the early 2000s. Since then, the so-called ‘bladders and keys’ procedure has become one of the reference techniques for the assembly of high-field accelerator magnets and demonstrators. Exploiting the advantages of this method is today of critical importance for Nb$_{3}$Sn-based accelerator magnets, whose production requires the preservation of tight stress targets in the superconducting coils to limit the effects of the strain sensitivity and brittleness of the conductor. The present manuscript reports on the results of an experimental campaign focused on the optimization of the ‘bladders and keys’ assembly process in the MQXFB quadrupoles. These 7.2 m long magnets shall be among the first Nb$_{3}$Sn cryomagnets to be installed in a particle accelerator as a part of the High Luminosity upgrade of the LHC. One of the main practical implications of the bladders technique, especially important when applied to long magnets like MQXFB, is that to insert the loading keys, the opening of a certain clearance in the support structure is required. The procedure used so far for MQXF magnets involved an overstress in the coils during bladder inflation. The work presented here shows that such an overshoot can be eliminated thanks to additional bladders properly positioned in the structure. This optimized method was validated in a short model magnet and in a full-length mechanical model, becoming the new baseline for the series production at CERN Furthermore, the results are supported by numerical predictions using finite element models. The use of pressurized bladders for stress control of superconducting magnets was firstly proposed at Lawrence Berkeley National Laboratory (LBNL) in the early 2000s. Since then, the so-called “bladders and keys” procedure has become one of the reference techniques for the assembly of high-feld accelerator magnets and demonstrators. Exploiting the advantages of this method is today of critical importance for Nb3Sn-based accelerator magnets, whose production requires the preservation of tight stress targets in the superconducting coils to limit the effects of the strain sensitivity and brittleness of the conductor. The present manuscript reports on the results of an experimental campaign focused on the optimization of the “bladders and keys” assembly process in the MQXFB quadrupoles. These 7.2 m long magnets shall be among the frst Nb3Sn cryomagnets to be installed in a particle accelerator as a part of the High Luminosity upgrade of the LHC. One of the main practical implications of the bladders technique, especially important when applied to long magnets like MQXFB, is that to insert the loading keys, the opening of a certain clearance in the support structure is required. The procedure used so far for MQXF magnets involved an overstress in the coils during bladder infation. The work presented here shows that such an overshoot can be eliminated thanks to additional bladders properly positioned in the structure. This optimized method was validated in a short model magnet and in a full-length mechanical model, becoming the new baseline for the series production at CERN. Furthermore, the results are supported by numerical predictions using Finite Element models. The use of pressurized bladders for stress control of superconducting magnets was firstly proposed at Lawrence Berkeley National Laboratory (LBNL) in the early 2000s. Since then, the so-called bladders and keys procedure has become one of the reference techniques for the assembly of high-field accelerator magnets and demonstrators. Exploiting the advantages of this method is today of critical importance for Nb3Sn-based accelerator magnets, whose production requires the preservation of tight stress targets in the superconducting coils to limit the effects of the strain sensitivity and brittleness of the conductor. The present manuscript reports on the results of an experimental campaign focused on the optimization of the bladders and keys assembly process in the MQXFB quadrupoles. These 7.2 m long magnets shall be among the first Nb3Sn cryomagnets to be installed in a particle accelerator as a part of the High Luminosity upgrade of the LHC. One of the main practical implications of the bladders technique, especially important when applied to long magnets like MQXFB, is that to insert the loading keys, the opening of a certain clearance in the support structure is required. The procedure used so far for MQXF magnets involved an overstress in the coils during bladder inflation. The work presented here shows that such an overshoot can be eliminated thanks to additional bladders properly positioned in the structure. This optimized method was validated in a short model magnet and in a full-length mechanical model, becoming the new baseline for the series production at CERN. Furthermore, the results are supported by numerical predictions using Finite Element models.

As a part of a collaborative effort with CERN on the long road to FCC-hh, CEA is developing a 1.4 m-long single aperture short dipole demonstrator. This Nb3Sn block dipole, named F2D2, is foreseen to produce 15.5 T with a 14% margin at 1.9 K, and will use a shell-based support structure. In order to be compact, this magnet relies on the use of different cable grades in each coil. Among the milestones in this project, a single-layer graded racetrack dipole will be constructed in order to demonstrate grading in a simplified geometry while preserving key features of F2D2. This magnet, named Research Racetrack Dipole Demonstrator (R2D2), will permit the mastering of the fabrication methods foreseen for F2D2 and to confirm the behavior of Nb3Sn cables representative of FCC. It should also validate some key technological aspects: compactness, operation at high-current (up to 16 kA), intermediate magnetic field (in the range of 11-12 T), and quench protection at very high energy/unit length (up to 650 kJ/m, corresponding to 168 MJ/m3).

International audience; In the framework of the HL-LHC project, a NbTi double aperture quadrupole magnet MQYY is being developed as an option to replace the LHC magnet MQY. This 90 mm double aperture cos-2θ quadrupole has an operating gradient of 120 T/m at 1.9 K. To demonstrate the validity of the design, a single aperture short model of 1.2 m called MQYYM has been developed. Designed by CEA and manufactured in collaboration with CERN, the MQYYM magnet is being prepared for cold test at CEA in a dedicated cryogenic station with LHe bath at 1 bar 4.2 K and 23 mbar 1.9 K. First, this paper will summarize the initial and as-built magnet designs based on the assembly at CERN. Second, updated mechanical measurements of collaring and axial pre-loading will be presented. Finally warm magnetic measurements performed at CERN during the assembly and at CEA during test preparation will be detailed.

High-field Nb3Sn dipoles generating more than 15 T are strongly required, whether it is for the future circular collider studies (CERN 16 T Development Program, CEA-CERN demonstrator) or for test stations (FRESCA2, HEPDipo). The use of magnets graded with different cables now becomes unavoidable to allow for more compact and cost-effective designs. This article presents a 2-D parametric study, which explores possible options for an optimal grading. The study uses analytical formulas for current sources to allow for fast and accurate parametric studies. Block coils are considered, using different cable sizes, and therefore, different current densities. Various parameters are also explored, such as cable combinations, current density ratios, conductor performance, and position of the blocks. The article shows in particular what are the optimal grading factors and amount of conductor required to reach a given bore field, considering margins on the load line, and limitations in current density for quench protection.

For the HL-LHC project, a 90 mm double aperture NbTi quadrupole magnet is being developed as an option to replace the 70 mm aperture LHC quadrupole MQY. This cos2θ magnet has an operating gradient of 120 T/m at 1.9 K and a magnetic length of 3.67 m. A single aperture short model magnet with a magnetic length of 1.2 m has been designed at CEA and is being manufactured in collaboration with CERN. The magnet support structure is relying on self-supporting collars. We present here the mechanical analysis along with the assembly of the short model magnet from coil fabrication and mechanical characterization to collaring and yoking.

F2D2, the FCC Flared-ends Dipole Demonstrator, is a 15 T single-aperture short model being developed within a collaboration between CEA Paris-Saclay and CERN. The design phase is ongoing at CEA; the magnet will be fabricated at CEA and then tested at CERN. The 2D magnetic and mechanical designs have been optimized previously and allowed defining the operating points and the required structural components. This paper reports on the preliminary design phase, focused on 3D mechanical optimizations of coils and structure. F2D2 will be the first Nb3Sn block-coil magnet using two cable grades. The cables will be spliced outside of the magnet, which represents one of the most complex design feature, and requires a special focus on the magnet ends. To do so, the design of the magnet has been performed using a CAD (Computer Aided Design) and both magnetic and mechanical 3D FEM (Finite-Elements Models). The CAD defines precisely the complex coil-ends shape that allows positioning the layer jumps and routing the cable exits. The FEM are used to optimize the longitudinal pre-load system in order to contain the large Lorentz forces during operation. The magnet is pre-loaded transversally with bladders and keys and with an external Al shell; and longitudinally with Al tie-rods and end-plates. The pre-load levels are computed to operate the magnet under sufficient compression, while minimizing the stress in the coil and avoid degradation.

International audience; R2D2, the Research Racetrack Dipole Demonstrator, is a short model being developed within a collaboration between CEA Paris-Saclay and CERN. The goal of the program is to develop key technologies for future high field 16 T Nb3Sn magnets for particle colliders. In the particular case of block-coil designs, two different cable grades are wound in the same coil layer, in order to maximize the current density, therefore to minimize the size of the magnet and the use of superconductor. One of the most challenging technologies with this grading concept, is the connection between two cables grades. CEA Paris-Saclay has proposed a concept of external joints, for which the cable exits are guided outside of the coil to perform the connections between the cable grades. The R2D2 project is aimed at demonstrating this technology in a representative demonstrator magnet, while simplifying and reducing the risks when possible, as an intermediate step towards 16 T magnets. In particular, the magnet is composed of single-layer racetrack coils, mainly to reduce the use of conductor and simplify some fabrication steps. However, the complexity inherent to the external joints requires a special focus in the design of the coil ends. To do so, the design of the magnet has been performed using a combination of CAD (Computer Aided Design), magnetic and mechanical 3D FEM (Finite-Elements Models). This paper will explain the design choices leading to a safe operation of the magnet in terms of peak fields and peak stresses.

The High Luminosity Large Hadron Collider (HL-LHC) is the new flagship project of CERN. First endorsed in 2013 and approved in 2016, HL-LHC is an upgrade of the accelerator aiming to increase by a factor of ten the statistics of the LHC collisions at the horizon of 2035–2040. HL-LHC relies on cutting edge technologies: among them, large aperture superconducting magnets will replace the present hardware to allow a smaller beam size in two interaction points (IPs). The project involves the construction of about 150 magnets of six different types: the quadrupole triplet, two main dipoles and three orbit correctors. The triplet, manufactured at CERN and in the USA, will consist of 30 magnets based on Nb3Sn technology, with an operational peak field of 11.4 T. These will be the first quadrupole Nb3Sn magnets installed in a particle accelerator. The other five types of magnets, all relying on Nb–Ti technology, present non-trivial challenges in the design and construction; they will be manufactured as part of in-kind contribution under the responsibility of institutes in Japan, China, Spain, and Italy. The project is now in the phase of transition between qualification through short models and prototypes and the beginning of the series construction. In this paper we review the magnet requirements, the reasons for selecting the design, the technological challenges with respect to previous projects, and we summarize the steps that have been taken to validate the baseline.

In the framework of the High-Luminosity Large Hadron Collider, the installation of a new generation of quadrupole magnets is foreseen on each side of ATLAS and CMS experiments. The new magnets are based on Nb3Sn technology and shall be able to reach an ultimate current of 17.9 kA with a peak field of 12.3 T in the coil. In 2016 and 2017, the first two short models, called MQXFS3 and MQXFS5, have been tested at 4.2 and 1.9 K in the two new test benches at the European Organization for Nuclear Research. This paper presents the result of the quench performance of the two models; the first magnet reached nominal but failed to reach ultimate, showing detraining in one coil. MQXFS5 reached ultimate performance without any detraining phenomena, validating the PIT conductor used for the first time in this magnet program.

The superconducting ECR source magnet for the Facility for Rare Isotope Beams at Michigan State University was designed and built by the Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL). The 28-GHz NbTi ion source magnet features a sextupole-in-solenoids configuration, which is comparable to the VENUS ECR magnet operated at LBNL. A shell-based support structure using bladders and keys has been incorporated into the design to allow for adjustments of the preload and reversibility of the magnet assembly process. The magnet has been assembled and successfully tested to operational currents at LBNL. This paper describes the basic design of the magnet and the passive quench protection system. The test results are also presented, including the quench behavior of the magnet, the training performance, and the magnetic measurement results.

Introduction: Although multiple defects of the atrial septum are not uncommon, there remain limited data regarding the use of multiple devices in these patients. A variety of approaches to transcatheter closure have been used, and in this paper we describe the experience from two operators in a single centre. Methods: From September 2002 to September 2012, 673 transcatheter atrial septal defects (ASD) and patent foramen ovale (PFO) closure procedures were performed and retrospectively examined in a registry analysis. Results: Of these, 22 patients had multiple discrete defects, and four different approaches to closure were used. In 4 patients (18.2%) one device was used percutaneously to close multiple defects. Eleven patients (50%) had two devices inserted during the same procedure while two patients (9%) had two devices inserted as staged procedures. One patient (4.5%) had three devices inserted over two procedures. Four patients (18.2%) were found not to be suitable for percutaneous closure during the procedure and were referred for surgical closure. Conclusion: Our experience with the implant procedures, and clinical follow up of patients, shows that patients with multiple defects can be effectively treated with transcatheter device techniques including single device closure, multiple devices in one procedure and multiple devices in staged procedures and also with surgical repair.

International audience; In the framework of the Hi-Lumi LHC Project, CERN and U.S. LARP are jointly developing MQXF, a 150-mm aperture high-field Nb3Sn quadrupole for the upgrade of the inner triplet of the low-beta interaction regions. The magnet is supported by a shell-based structure, providing the preload by means of bladder-key technology and differential thermal contraction of the various components. Two short models have been produced using the same cross section currently considered for the final magnet. The structures were preliminarily tested replacing the superconducting coils with blocks of aluminum. This procedure allows for model validation and calibration, and also to set performance goals for the real magnet. Strain gauges were used to monitor the behavior of the structure during assembly, cool down and also excitation in the case of the magnets. The various structures differ for the shell partitioning strategies adopted and for the presence of thick or thin laminations. This paper presents the results obtained and discusses the mechanical performance of all the short models produced up to now.

© 2015 IEEE. In preparation for the high-luminosity upgrade of the Large Hadron Collider (LHC), the LHC Accelerator Research Program (LARP) in collaboration with CERN is pursuing the development of MQXF: a 150-mm-aperture high-field Nb3Sn quadrupole magnet. The development phase starts with the fabrication and test of several short models (1.2-m magnetic length) and will continue with the development of several long prototypes. All of them are mechanically supported using a shell-based support structure, which has been extensively demonstrated on several RD models within LARP. The first short model MQXFS-AT has been assembled at LBNL with coils fabricated by LARP and CERN. In this paper, we summarize the assembly process and show how it relies strongly on experience acquired during the LARP 120-mm-aperture HQ magnet series. We present comparison between strain gauges data and finite-element model analysis. Finally, we present the implication of the MQXFS-AT experience on the design of the long prototype support structure.

No abstract available - Guidelines

As part of a collaboration between CEA/Saclay and the Superconducting Magnet Group at LBNL, a subscale dipole structure has been developed to study training in Nb3Sn coils under variable pre-stress conditions. This design is derived from the LBNL Subscale Magnet and relies on the use of identical Nb3Sn racetrack coils. Whereas the original LBNL subscale magnet was in a dual bore "common-coil" configuration, the new subscale dipole magnet (SD) is assembled as a single bore dipole made of two superposed racetrack coils. The dipole is supported by a new mechanical structure developed to withstand the horizontal and axial Lorentz forces and capable of applying variable vertical, horizontal and axial preload. The magnet was tested at LBNL as part of a series of training studies aiming at understanding of the relation between pre-stress and magnet performance. Particular attention is given to the coil ends where the magnetic field peaks and stress conditions are the least understood. After a description of SD design, assembly, cool-down and tests results are reported and compared with the computations of the OPERA3D and ANSYS magnetic and mechanical models.

Introduction Takotsubo cardiomyopathy is the acquired, reversible syndrome characterised by apical ballooning and base hypercontractility and probably precipitated by emotional and physical stressors that cause a hyperadrenergic state. It presents as an acute coronary event without there being coronary disease. Case presentation We present a case of a 73-year-old woman who developed takotsubo cardiomyopathy with concomitant septic shock from a chronic hemiarthroplasty site infection. The prosthesis had been removed, the surgical site drained twice and multiple antibiotics prescribed. She also had a previous episode of sepsis from she recovered with vasopressor support. Conclusion To the author’s knowledge, this is the first case of this syndrome occurring in such a prolonged septic process and where the primary focus was a surgical wound. This may indicate continued myocardial injury secondary to a sustained hyperadrenergic state as a possible mechanism for takotsubo cardiomyopathy, rather than a one-time catecholamine surge.

Transcatheter closure of atrial septal defects and patent foramen ovale is now a well established therapeutic option. In this paper, we illustrate, step by step, the technique of Amplatzer ASO closure of these defects.

Glyceryl trinitrate (nitroglycerin) has been in use for relief of angina for over a hundred years, but allergic reactions to it or to other organic nitrates rarely feature in the medical literature. Most of the case reports describe reactions to transdermally applied nitroglycerin. We report a case of a localized allergic reaction to nitroglycerin transdermal patches that developed when these were worn for the first time after 7 days of uneventful treatment with intravenous isosorbide dinitrate. The reaction evolved into a severe and generalized maculopapular rash with facial swelling when intravenous isosorbide dinitrate was re-administered 10 days later. Subsequent patch testing with a transdermal nitroglycerin patch and a placebo nitroglycerin-free patch provoked a reaction to the nitroglycerin patch but not to the placebo, thus excluding allergy to other constituents of the nitroglycerin patch.

We developed a series of interrelated locus-specific databases to store all published and unpublished genetic variation related to hemoglobinopathies and thalassemia and implemented microattribution to encourage submission of unpublished observations of genetic variation to these public repositories. A total of 1,941 unique genetic variants in 37 genes, encoding globins and other erythroid proteins, are currently documented in these databases, with reciprocal attribution of microcitations to data contributors. Our project provides the first example of implementing microattribution to incentivise submission of all known genetic variation in a defined system. It has demonstrably increased the reporting of human variants, leading to a comprehensive online resource for systematically describing human genetic variation in the globin genes and other genes contributing to hemoglobinopathies and thalassemias. The principles established here will serve as a model for other systems and for the analysis of other common and/or complex human genetic diseases. © 2011 Nature America, Inc. All rights reserved.

The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb$_3$Sn quadrupole models. The Long Quadrupoles (LQ) are ldquoProof-of-Principlerdquo magnets which are to demonstrate that Nb$_3$Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. The plans for the LQ R&D; and a design update are presented and discussed in this paper. The challenges of fabricating long accelerator-quality Nb$_3$Sn coils are presented together with the solutions adopted for the LQ coils (based on the TQ experience). During the fabrication and inspection of practice coils some problems were found and corrected. The fabrication at BNL and FNAL of the set of coils for the first Long Quadrupole is in progress.

Plans for LHC upgrade and for the final focalization of linear colliders call for large aperture and/or high-performance dipole and quadrupole magnets that may be beyond the reach of conventional NbTi magnet technology. The Next European Dipole (NED) activity was launched on January 1st, 2004 to promote the development of high-performance, Nb/sub 3/Sn wires in collaboration with European industry (aiming at a noncopper critical current density of 1500 A/mm/sup 2/ at 4.2 K and 15 T) and to assess the suitability of Nb/sub 3/Sn technology to the next generation of accelerator magnets (aiming at an aperture of 88 mm and a conductor peak field of 15 T). It is integrated within the Collaborated Accelerator Research in Europe (CARE) project, involves seven collaborators, and is partly funded by the European Union. We present here an overview of the NED activity and we report on the status of the various work packages it encompasses.

Glyceryl trinitrate (nitroglycerin) has been in use for relief of angina for over a hundred years, but allergic reactions to it or to other organic nitrates rarely feature in the medical literature. Most of the case reports describe reactions to transdermally applied nitroglycerin. We report a case of a localized allergic reaction to nitroglycerin transdermal patches that developed when these were worn for the first time after 7 days of uneventful treatment with intravenous isosorbide dinitrate. The reaction evolved into a severe and generalized maculopapular rash with facial swelling when intravenous isosorbide dinitrate was re-administered 10 days later. Subsequent patch testing with a transdermal nitroglycerin patch and a placebo nitroglycerin-free patch provoked a reaction to the nitroglycerin patch but not to the placebo, thus excluding allergy to other constituents of the nitroglycerin patch.

BACKGROUND The exercise-induced rise in left ventricular filling pressures after cardiac transplantation is considered to be the result of a blunted heart rate response, of elevated venous return, and of unfavorable passive late-diastolic properties of the cardiac allograft. In contrast to passive late-diastolic left ventricular properties, the effect of left ventricular relaxation on the exercise-induced rise in left ventricular filling pressures of the cardiac allograft has not yet been studied. In the present study, the response of left ventricular relaxation to exercise was investigated in transplant recipients and compared with left ventricular relaxation observed in normal control subjects exercised to the same heart rate. Moreover, the response of left ventricular relaxation of the cardiac allograft to beta-adrenoreceptor stimulation, to reduced left ventricular afterload, and to increased myocardial activator calcium was investigated by infusion of dobutamine and of nitroprusside and by postextrasystolic potentiation. METHODS AND RESULTS Twenty-seven transplant recipients were studied 1 year (n = 17), 2 years (n = 7), 3 years (n = 2), and 4 years (n = 1) after transplantation. All patients were free of rejection and of significant graft atherosclerosis at the time of study. Tip-micromanometer left ventricular pressure recordings and cardiac hemodynamics were obtained at rest, during supine bicycle exercise stress testing (n = 27), during dobutamine infusion at a heart rate matching the heart rate at peak exercise (n = 8), during nitroprusside infusion (n = 9), and after postextrasystolic potentiation (n = 10). Tip-micromanometer left ventricular pressure recordings were also obtained in a normal control group (n = 9) at rest and during supine bicycle exercise stress testing to a heart rate, which matched the heart rate of the transplant recipient group at peak exercise. Left ventricular relaxation rate was measured by calculation of a time constant of left ventricular pressure decay (T) derived from an exponential curve fit to the digitized tip-micromanometer left ventricular pressure signal. In the transplant recipients, exercise abbreviated T from 43 +/- 6 to 40 +/- 8 msec (p less than 0.01) and caused a rise of left ventricular minimum diastolic pressure (LVMDP) from 5 +/- 2 to 9 +/- 6 mm Hg (p less than 0.001). In normal control subjects, exercise induced a 2.5 times larger abbreviation of T (from 42 +/- 7 to 34 +/- 6 msec; p less than 0.001) and a small drop in LVMDP from 5 +/- 2 to 4 +/- 3 mm Hg (p less than 0.05). In the transplant recipients, the change in T (delta T) from rest to exercise was variable ranging from an abbreviation, as observed in normal controls, to a prolongation and was significantly correlated with the change in RR interval (delta RR) and the change in left ventricular end-diastolic pressure (delta LVEDP) (delta T = 0.068 delta RR + 0.58 delta LVEDP-2.2; r = 0.76; p less than 0.001). In a first subset of transplant recipients (n = 8), dobutamine infusion resulted in a heart rate equal to the heart rate at peak exercise, a left ventricular end-diastolic pressure (8 +/- 7 mm Hg) lower than at peak exercise (22 +/- 6 mm Hg; p less than 0.05) and a T value (32 +/- 9 msec), which was shorter than both resting value (44 +/- 5 msec; p less than 0.005) and value observed at peak exercise (40 +/- 8 msec; p less than 0.01). In a second subset of transplant recipients (n = 9), nitroprusside infusion and postextrasystolic potentiation resulted in a significant prolongation of T from 41 +/- 7 to 56 +/- 10 msec (p less than 0.05) and a characteristic negative dP/dt upstroke pattern with downward convexity as previously observed in left ventricular hypertrophy. CONCLUSIONS Exercise after cardiac transplantation resulted in a smaller acceleration of left ventricular relaxation than in a normal control group exercised to the same heart rate...

Effects of a dietary deficiency of vitamin B-6 imposed during the lactation period on the level of this vitamin in milk, liver and muscle were assessed in rats. A control diet (vitamin B-6 free basal diet supplemented with 10 mg pyridoxine . HCl/kg) was fed to all rats just before and during the gestation period. On day 1 of lactation, dams were randomly assigned to three dietary treatment groups: deficient (vitamin B-6 free basal diet), control or restricted control (control diet restricted in quantity to that consumed by the deficient group). Levels of total vitamin B-6 in milk, liver and muscle were determined by microbiological assay on days 1, 6, 16 and 21 of lactation. On day 6, the concentration of vitamin B-6 in milk of deficient dams was less than 20% of control or restricted control values. The low level of vitamin B-6 in milk of the deficient group continued to be evident on days 16 and 21 whereas in control and restricted control groups the vitamin content increased on days 16 and 21 compared to the values on day 6. In contrast to the low level of vitamin B-6 content observed in milk on day 6 in the deficient group, the vitamin content in liver of this group was approximately 75% of control or restricted control values, and the vitamin content in muscle was not significantly altered by the deficiency. Hence, milk was effected sooner by the deficiency and was an earlier indicator of impending vitamin B-6 deficiency than was liver or muscle tissues.

The quench protection of the several meter long, large aperture high-field Nb3Sn quadrupoles that the LARP collaboration is developing for the LHC interaction region upgrade, requires efficient protection heaters to quickly generate large resistive segments across the windings. To support the protection design, experiments in the recently tested LARP R&D magnets are aimed to characterize the coil response to different protection schemes. In particular, the delay to quench and the final hotspot temperatures are evaluated after firing the heaters at different powering regimes and coverage. Also, the contribution of external energy extraction is investigated. Based on the performed studies and computer simulations, it seems that if the same protection efficiency per unit length that is measured in a 1 m long model magnet can be scaled to a 3.6 m long magnet, and the heater coverage can be improved, about 1 MJ/m of stored energy can be absorbed in the magnet after a quench. However, significant technology dev...