15,421 research outputs found
Tubular Krukenberg Tumor with an Occult Primary
Tubular Krukenberg tumor with an occult primary can cause problems in histopathologic diagnosis, by mimicking primary ovarian tumors. We present one such occurrence in a 32year old female who underwent surgery for bilateral malignant ovarian tumor. Gross examination of both ovarian tumors revealed bosselated, smooth outer surface with a few cysts on the surface. Cut surface was grey-white to yellowish in colour with cysts filled with serous fluid at the periphery. Microscopic examination revealed mucin laden signet ring cells, predominantly showing tubular architecture within a cellular ovarian stroma. The cytoplasm of these cells varied from granular eosinophilic to pale vacuolated appearance and showed PAS and mucicarmine positive mucin. Differential diagnosis with other primary ovarian tumors is discussed
Re-imagining the Froebelian influence on early childhood education as a dynamic and ever-changing web of encounter
Friedrich Froebel is often positioned in contemporary landscapes of early childhood education as a ‘pioneer’, strongly associated with an emphasis on self-directed activity and learning through nature. While Froebel’s philosophy has clearly had an impact on how we think about young children today, in this article we argue that we need to re-imagine what counts as Froebel’s influence so that it goes well beyond the sayings and doings of one individual. In line with this special issue, we seek to bewilder the concept of the pioneer (Snaza, 2013) by instead re-imagining Froebel’s influence as a dynamic and ever-changing web of encounter. In conceptualising this web of encounter, we think with Barad’s (2007) ‘entangled genealogies’ and introduce into working with these genealogies, the historical methods of prosopography and material histories of the book. Using digitised extracts from late 19th century texts by or about Froebel as a starting point, we attempt to present small parts of a web of encounter drawing in complex national, cultural, economic and material contexts, along with the contributions of multiple individuals, many of whom have been forgotten or side-lined. We argue that exploring and documenting Froebel’s influence in this way can support critical and lively reflection on the past, present and future of early childhood education
Identification and characterization of the dominant thermal resistance in lithium-ion batteries using operando 3-omega sensors
Poor thermal transport within lithium-ion batteries fundamentally limits their performance, safety, and lifetime, in spite of external thermal management systems. All prior efforts to understand the origin of batteries' mysteriously high thermal resistance have been confined to ex situ measurements without understanding the impact of battery operation. Here, we develop a frequency-domain technique that employs sensors capable of measuring spatially resolved intrinsic thermal transport properties within a live battery while it is undergoing cycling. Our results reveal that the poor battery thermal transport is due to high thermal contact resistance between the separator and both electrode layers and worsens as a result of formation cycling, degrading total battery thermal transport by up to 70%. We develop a thermal model of these contact resistances to explain their origin. These contacts account for up to 65% of the total thermal resistance inside the battery, leading to far-reaching consequences for the thermal design of batteries. Our technique unlocks new thermal measurement capabilities for future battery research
Nonstandard electroconvection in a bent-core oxadiazole material
Electroconvection (EC) phenomena have been investigated in the nematic phase of a bent-core oxadiazole material with negative dielectric anisotropy and a frequency dependent conductivity anisotropy. The formation of longitudinal roll (LR) patterns is one of the predominant features observed in the complete frequency and voltage range studied. At voltages much above the LR threshold, various complex patterns such as the "crisscrossed" pattern, bimodal varicose, and turbulence are observed. Unusually, the nonstandard EC (ns-EC) instability in this material, is observed in a regime in which we measure the dielectric and conductivity anisotropies to be negative and positive respectively. A further significant observation is that the EC displays distinct features in the high and low temperature regimes of the nematic phase, supporting an earlier report that EC patterns could distinguish between regions that have been reported as uniaxial and biaxial nematic phases
Cholecalciferol supplementation and angiogenic markers in chronic kidney disease
Vitamin D plays an important role in proliferation and differentiation of cells and deficiency of vitamin D disturbs angiogenic balance. Previous studies in animal models have reported an association between serum levels of vitamin D and balance between pro- and anti-angiogenic factors. There is insufficient evidence about the effect of vitamin D on mediators of angiogenesis in patients with CKD. We investigated the effect of cholecalciferol supplementation on serum levels of angiogenic markers in non-diabetic patients with CKD stage 3-4. In this secondary analysis on stored samples of our previously published randomized, double-blind, placebo-controlled trial, stable patients of either sex, aged 18-70 years, with non-diabetic CKD stage 3-4 and vitamin D deficiency (serum 25-hydroxyvitamin D ≤20 ng/ml) were randomized to receive either two directly observed oral doses of cholecalciferol (300,000 IU) or matching placebo at baseline and 8 weeks. The primary outcome was change in brachial artery flow-mediated dilatation at 16 weeks. Changes in levels of serum angiogenesis markers (angiopoietin-1, angiopoietin-2, VEGF-A, VEGEF-R, and Tie-2) between groups over 16 weeks were compared. A total 120 patients were enrolled. Supplementation with cholecalciferol led to significant improvement in FMD. Serum 25(OH)D levels were similar in both groups at baseline (13.21±4.78 ng/ml and 13.40±4.42 ng/ml; p = 0.888). At 16 weeks, the serum 25(OH)D levels increased in the cholecalciferol group but not in the placebo group (between-group difference in mean change:23.40 ng/ml; 95% CI, 19.76 to 27.06; p<0.001). Serum levels of angiogenic markers were similar at baseline. At 16 weeks, angiopoietin-2 level decreased in cholecalciferol group (mean difference:-0.73 ng/ml, 95%CI, -1.25 to -0.20, p = 0.002) but not in placebo group (mean difference -0.46 ng/ml, 95%CI, -1.09 to 0.17, p = 0.154), however there was no between-group difference at 16 weeks (between-group difference in mean change: -0.27 ng/ml, 95%CI, -1.09 to 0.55, p = 0.624). Serum angiopoietin-1 level increased [mean change: 5.63 (0.51 to 10.75), p = 0.018] and VEGF-R level decreased [mean change: -87.16 (-131.89 to -42.44), p<0.001] in placebo group but did not show any change in cholecalciferol group. Our data shows the changes in Ang-1, Ang-2 and Ang-1/Ang-2 ratio after high dose oral cholecalciferol supplementation in patients with non-diabetic G3-4 CKD. The data suggests changes in circulating levels of angiogenic markers which needs to be confirmed through an adequately powered study
Helical vortex phase in the non-centrosymmetric CePt_3Si
We consider the role of magnetic fields on the broken inversion
superconductor CePt_3Si. We show that upper critical field for a field along
the c-axis exhibits a much weaker paramagnetic effect than for a field applied
perpendicular to the c-axis. The in-plane paramagnetic effect is strongly
reduced by the appearance of helical structure in the order parameter. We find
that to get good agreement between theory and recent experimental measurements
of H_{c2}, this helical structure is required. We propose a Josephson junction
experiment that can be used to detect this helical order. In particular, we
predict that Josephson current will exhibit a magnetic interference pattern for
a magnetic field applied perpendicular to the junction normal. We also discuss
unusual magnetic effects associated with the helical order.Comment: 5 pages, 2 figures, Accepted as Phys Rev. Lette
Entropic Analysis of Votes Expressed in Italian Elections between 1948 and 2018
In Italy, the elections occur often, indeed almost every year the citizens are involved in a democratic choice for deciding leaders of different administrative entities. Sometimes the citizens are called to vote for filling more than one office in more than one administrative body. This phenomenon has occurred 35 times after 1948; it creates the peculiar condition of having the same sample of people expressing decisions on political bases at the same time. Therefore, the Italian contemporaneous ballots constitute the occasion to measure coherence and chaos in the way of expressing political opinion. In this paper, we address all the Italian elections that occurred between 1948 and 2018. We collect the number of votes per party at each administrative level and we treat each election as a manifestation of a complex system. Then, we use the Shannon entropy and the Gini Index to study the degree of disorder manifested during different types of elections at the municipality level. A particular focus is devoted to the contemporaneous elections. Such cases implicate different disorder dynamics in the contemporaneous ballots, when different administrative level are involved. Furthermore, some features that characterize different entropic regimes have emerged
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