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Recent advances with additive manufacturing (AM) technologies using various materials allow them to be considered for the manufacture of precise and complicated metal parts of the magnet coils of high field accelerator magnets from aluminum bronze, titanium alloy, stainless steel, etc. The 3D printing technology is also being used to fabricate prototype models of real parts to test and optimize their geometry. This paper discusses the designs of the complex stress-management coil parts developed at Fermilab, their fabrication using AM technologies, and quality control methods and results.

Background Remodeling of the left ventricle with the development of a spherical cavity occurs in dilated cardiomyopathy and is associated with a poor long-term prognosis. The early effects of myocarditis on left ventricular geometry have not been previously described or correlated with clinical outcome. Methods The baseline echocardiograms of 35 patients with biopsy-confirmed myocarditis were compared with 20 normal controls. Left ventricular end-diastolic volume, long axis length, and mid-cavity diameter were measured. The degree of sphericity was expressed as the ratio of the mid-cavity diameter to the long axis length. Left ventricular ejection fraction was assessed by radionuclide angiography. Results In patients with myocarditis, mean left ventricular volume of 81 +/- 29 mL/m^2 was significantly greater than 50 +/- 8 mL/m^2 in controls (P = .001). Chamber dilatation occurred primarily along the mid-cavity diameter, which measured 5.3 +/- 0.8 cm in patients with myocarditis versus 4.2 +/- 0.4 cm in controls (P = .001). The degree of left ventricular sphericity in patients with myocarditis, 0.64 +/- 0.08, was significantly greater than that of controls, 0.54 +/- 0.04 (P = .001). When patients were stratified according to left ventricular volume, patients with increased left ventricular volume (>75 mL/m^2) were associated with a more spherical chamber and lower left ventricular ejection fraction than patients with a more normal left ventricular volume (@?75 mL/m^2). Conclusions Active myocarditis is associated with early left ventricular remodeling and the development of a spherical chamber. These changes correlate with ventricular dilatation and reduced left ventricular ejection fraction. (Am Heart J 1999;138:303-8.)

1. Changes in extracellular K+ activity were measured with ion‐selective microelectrodes in the grey matter of the isolated hemisected frog spinal cord. The magnitude of the elevation of [K+]o (delta[K+]o) produced by repetitive stimulation (25 Hz, 10 s) of afferent fibres in the sciatic nerve was monotonically related to the strength of the electrical stimuli applied to the sciatic nerve. Repetitive stimulation of the largest diameter A alpha and A beta fibres, which were found histologically to comprise only 11% of the afferent axons in the dorsal root, elevated [K+]o to approximately 60% of the maximum level seen when all afferent fibres were stimulated. 2. Addition of Mg2+ (20 mM) to Ringer solution devoid of Mg2+ reduced delta[K+]o by over 85% suggesting that about 15% of delta[K+]o results from action potentials in presynaptic primary afferents. When 20 mM‐Mg2+ was added to spinal cords bathed in Ringer solution containing a physiological (i.e. 1.0 mM) concentration of Mg2+, delta[K+]o was reduced by ca. 65‐75% indicating that in spinal cords bathed in medium containing 'physiological' concentrations of Mg2+ about 25‐35% of the K+ is released from primary afferent fibres. 3. Application of excitatory amino acids and agonists increased [K+]o with the following potency pattern: quisqualate greater than kainate greater than NMDA (N‐methyl‐D‐aspartate) greater than glutamate greater than aspartate. 4. D(‐)‐2‐Amino‐5‐phosphonovalerate (APV), an NMDA antagonist, reduced [K+]o by only about 50%, but kynurenate, an NMDA and non‐NMDA antagonist, reduced [K+]o by approximately 85%; i.e. the same levels observed when synaptic transmission was blocked with 20 mM‐Mg2+. These findings support the idea that synaptic release of excitatory amino acids such as L‐glutamate and/or L‐aspartate and subsequent activation of specific receptors by these putative transmitters are necessary for the postsynaptic component of delta[K+]o. 5. Addition of tachykinins elevated [K+]o but the effect appeared to require the participation of excitatory amino acids because it was blocked by APV and by kynurenate. 6. The finding that tetrodotoxin substantially reduced the ability of excitatory amino acid agonists and tachykinins to elevate [K+]o suggests that discharges in interneurones as a result of excitatory amino acid receptor activation are responsible for the postsynaptic component of delta[K+]o.

1. In the isolated frog spinal cord repetitive stimulation of a lumbar dorsal root produced a sustained negative potential recorded from an adjacent inactive dorsal root by sucrose gap techniques. This negative potential was followed by a positive potential, an indication that the dorsal root terminals were hyperpolarized. Increasing the duration of the tetanus applied to the active root increased the amplitude and duration of the after‐hyperpolarization which could be up to 6 mV and 3 min respectively. 2. The hyperpolarization presumably reflected an increased rate of active sodium pumping. Since it was reversibly reduced by metabolic inhibitors (dinitrophenol, NaCN) and cooling (Q10, 2 . 6) it was clearly dependent upon intact metabolic activity. In addition, a variety of procedures used to inhibit sodium pumps (including application of ouabain, elimination of potassium from the superfusate, and partial substitution of lithium for sodium ions) significantly and reversibly decreased the potential. 3. The hyperpolarization was not dependent upon intact chemical synaptic transmission since it could survive prolonged immersion of the cord in Ringer solution containing manganese or magnesium ions. 4. It is suggested that the hyperpolarization of inactive fibres resulted from a decreased extracellular potassium concentration in the dorsal horn produced as a result of a pumping mechanism which extruded sodium and transported potassium inwards by dorsal root fibres directly activated by the tetanus.

To determine whether the increased prevalence of congestive heart failure in women compared with men undergoing diagnostic cardiac catheterization is the result of a difference in the left ventricular pressure/volume relation, we retrospectively compared the clinical characteristics, left ventricular ejection fraction, and end-diastolic pressure and volume in 586 women and 1081 men undergoing diagnostic coronary angiography and left ventriculography. In comparison with men, women were older (63 vs 60 years; p = 0.0001) and had more hypertension (41% vs 31%; p = 0.0001), diabetes (18% vs 12%; p = 0.003), and symptoms of congestive heart failure (13% vs 10%; p = 0.05). In spite of this, women had a better mean left ventricular ejection fraction (61% vs 56%; p = 0.0001) and less prevalent three-vessel disease (23% vs 34%; p = 0.0001). Left ventricular end-diastolic volume index was smaller in women compared with men (73 vs 79 ml/m ^2 ; p = 0.0001) in spite of having similar left ventricular end-diastolic pressure. When patients were stratified according to left ventricular end-diastolic pressure, women had a significantly smaller end-diastolic volume than men did when left ventricular end-diastolic pressure was >=18 mm Hg (74 vs 86 ml/m ^2 ; p = 0.0001). In a multivariate analysis, female sex remained an independent predictor of congestive heart failure (odds ratio 1.72, 95% confidence interval 1.11 to 2.66, p = 0.02). This study suggests that diastolic dysfunction is one mechanism for the paradox of more frequent heart failure symptoms in spite of better preserved left ventricular systolic function in women. Sex appears to influence the pattern of myocardial dysfunction in patients with known or suspected coronary artery disease, but the basis for this observation remains speculative.(Am Heart J 1997;134:207-12.)