392 research outputs found
Microscopic theory for nonequilibrium correlation functions in dense active fluids
One of the key hallmarks of dense active matter in the liquid, supercooled,
and solid phases is so-called equal-time velocity correlations. Crucially,
these correlations can emerge spontaneously, i.e., they require no explicit
alignment interactions, and therefore represent a generic feature of dense
active matter. This indicates that for a meaningful comparison or possible
mapping between active and passive liquids one not only needs to understand
their structural properties, but also the impact of these velocity
correlations. This has already prompted several simulation and theoretical
studies, though they are mostly focused on athermal systems and thus overlook
the effect of translational diffusion. Here we present a fully microscopic
method to calculate nonequilibrium correlations in systems of thermal active
Brownian particles (ABPs). We use the integration through transients (ITT)
formalism together with (active) mode-coupling theory (MCT) and analytically
calculate qualitatively consistent static structure factors and active velocity
correlations. We complement our theoretical results with simulations of both
thermal and athermal ABPs which exemplify the disruptive role that thermal
noise has on velocity correlations
Parathyroid scintigraphy findings in chronic kidney disease patients with recurrent hyperparathyroidism
Background Parathyroidectomy (PTX), either subtotal or total with forearm autografting, is a well-established treatment for refractory renal hyperparathyroidism (RHPT). However, 20–30% of patients develop persistent or recurrent disease. Obtaining accurate localization before reoperation is difficult. Patients and methods The study group comprised 21 consecutive adult patients (18 undergoing haemodialysis and 3 with a renal graft) imaged using 99mTc-sestamibi/123I subtraction scintigraphy. Of the 21 patients, 12 had undergone one previous PTX and the other 9 between two and four parathyroid operations. All patients had symptoms and signs of severe RHPT. The mean serum PTH level was 1,142 pg/ml. 99mTc-Sestamibi and 123I images were recorded simultaneously. Imaging views comprised a planar view of the neck and mediastinum, followed by a magnified pinhole view over the thyroid bed area. If parathyroid ectopy was detected, SPECT or SPECT-CT was performed. The forearm was imaged in case of autograft. Results Parathyroid scintigraphy was negative in one patient and positive in the other 20 (sensitivity 95.2%). One patient had uptake corresponding to two unresected parathyroid glands. Recurrence at the site of the partially resected gland or autograft was seen in 11 patients. However, six of them had a second 99mTc-sestamibi focus corresponding to a supernumerary parathyroid gland. Seven other patients had a supernumerary parathyroid gland as the sole cause of relapse. Three of the supernumerary glands showed major ectopy (intrathyroidal, low mediastinal, undescended within the vagus nerve). One patient had parathyromatosis with multiple parathyroid nodules scattered over the left side of the neck. Reoperation was possible in 13 patients, with no false-positive findings. Conclusion Many patients referred with the hypothesis of hyperplasia of a subtotally resected parathyroid gland or autograft were found to harbour a supernumerary parathyroid gland missed at the initial surgery
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