A universal relationship between magnetization and local structure changes below the ferromagnetic transition in La_{1-x}Ca_xMnO_3; evidence for magnetic dimers

We present extensive X-ray Absorption Fine Structure (XAFS) measurements on La_{1-x}Ca_xMnO_3 as a function of B-field (to 11T) and Ca concentration, x (21-45%). These results reveal local structure changes (associated with polaron formation) that depend only on the magnetization for a given sample, irrespective of whether the magnetization is achieved through a decrease in temperature or an applied magnetic field. Furthermore, the relationship between local structure and magnetization depends on the hole doping. A model is proposed in which a filamentary magnetization initially develops via the aggregation of pairs of Mn atoms involving a hole and an electron site. These pairs have little distortion and it is likely that they pre-form at temperatures above T_c.Comment: 5 pages, 5 figures (1 with 2 parts) -- v2. new data added (updated figures); discussion expande

The EPRI DFDX Chemical Decontamination Process

Decommissioning of retired nuclear plants and components demands the proper management of the process, both for economic reasons and for retaining public confidence in the continued use of nuclear power for electricity generation. The cost and ease of management of radioactively contaminated components can be greatly assisted by the application of decontamination technology. EPRI initiated a program of research and development work in collaboration with Bradtec, which has led to the ''EPRI DFD'' (Decontamination for Decommissioning) Process. The Process has been patented and licensed to six companies worldwide. The purpose of this process is to achieve efficient removal of radioactivity with minimum waste from retired nuclear components and plant systems. The process uses dilute fluoroboric acid with controlled oxidation potential. By removing all the outer scale and a thin layer of base metal from the surfaces, contamination can in many cases be reduced below the levels required to allow clearance (free-release) or recycle to form new components for the nuclear industry. This reduces the need for on-site storage or burial of large amounts of contaminated material at low level radioactive disposal facilities. An additional benefit is that residual radiation fields can be reduced by a large factor, which reduces the worker radiation exposure associated with decommissioning. Furthermore, this dose rate reduction improves the viability of early dismantlement following plant closure, as opposed to waiting for a prolonged period for radioactive decay to occur. The results obtained in early applications of the EPRI DFD process demonstrated the benefits of taking this approach (reference 1)

An Osmotic Model of the Growing Pollen Tube

Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip

The Early Royal Society and Visual Culture

Recent studies have fruitfully examined the intersection between early modern science and visual culture by elucidating the functions of images in shaping and disseminating scientific knowledge. Given its rich archival sources, it is possible to extend this line of research in the case of the Royal Society to an examination of attitudes towards images as artefacts –manufactured objects worth commissioning, collecting and studying. Drawing on existing scholarship and material from the Royal Society Archives, I discuss Fellows’ interests in prints, drawings, varnishes, colorants, images made out of unusual materials, and methods of identifying the painter from a painting. Knowledge of production processes of images was important to members of the Royal Society, not only as connoisseurs and collectors, but also as those interested in a Baconian mastery of material processes, including a “history of trades”. Their antiquarian interests led to discussion of painters’ styles, and they gradually developed a visual memorial to an institution through portraits and other visual records.AH/M001938/1 (AHRC

Low-Level Liquid Waste Processing Pilot Studies Using a Vibratory Shear Enhancing Process (VSEP) for Filtration

A previous EPRI study evaluated potential treatment methods for the removal of iron from BWR waste streams. Of the methods investigated, high shear filtration using the vibratory shear-enhanced process (VSEP) showed the most promise to effectively and economically remove high iron concentrations from backwash receiving tank waste. A VSEP filter uses oscillatory vibration to create high shear at the surface of the filter membrane. This high shear force significantly improves the filter's resistance to fouling thereby enabling high throughputs with very little secondary waste generation. With a VSEP filter, the waste feed stream is split into two effluents- a permeate stream with little or no suspended solids and a concentrate stream with a suspended solids concentration much higher than that of the feed stream. To evaluate the feasibility of using a VSEP concept for processing typical high iron containing BWR radwaste, a surrogate feedstream containing up to 1,700 ppm iron oxide (as Fe2O3) was used. This surrogate waste simulates radioactive waste found at Exelon's Limerick and Peach Bottom (powdered resin condensate) plants, and in Hope Creek's (deep bed condensate) radwaste systems. Testing was done using a series L (laboratory scale) VSEP unit at the manufacturer's and contractor's laboratories. These tests successfully demonstrated the VSEP capability for producing highly concentrated waste streams with totally ''recyclable'' permeate (e.g., greater than 95% recovery)

Il diritto del Duce. Giustizia e repressione nell’Italia fascista

Attraverso l'analisi dei protagonisti istituzionali, dei codici, degli organismi giudiziari, delle logiche e delle pratiche politico-giuridiche, il volume delinea il processo di torsione in chiave repressiva che gli organi di giustizia hanno subito durante il ventennio all'interno di un quadro di asserita legalità, evidenziando altresì l'influsso che i 'discorsi della giustizia' hanno avuto sulle forme giuridiche, politiche, istituzionali del fascismo

Synthetic high-density lipoprotein nanoparticles for the treatment of Niemann–Pick diseases

Abstract Background Niemann–Pick disease type C is a fatal and progressive neurodegenerative disorder characterized by the accumulation of unesterified cholesterol in late endosomes and lysosomes. We sought to develop new therapeutics for this disorder by harnessing the body’s endogenous cholesterol scavenging particle, high-density lipoprotein (HDL). Methods Here we design, optimize, and define the mechanism of action of synthetic HDL (sHDL) nanoparticles. Results We demonstrate a dose-dependent rescue of cholesterol storage that is sensitive to sHDL lipid and peptide composition, enabling the identification of compounds with a range of therapeutic potency. Peripheral administration of sHDL to Npc1 I1061T homozygous mice mobilizes cholesterol, reduces serum bilirubin, reduces liver macrophage size, and corrects body weight deficits. Additionally, a single intraventricular injection into adult Npc1 I1061T brains significantly reduces cholesterol storage in Purkinje neurons. Since endogenous HDL is also a carrier of sphingomyelin, we tested the same sHDL formulation in the sphingomyelin storage disease Niemann–Pick type A. Utilizing stimulated Raman scattering microscopy to detect endogenous unlabeled lipids, we show significant rescue of Niemann–Pick type A lipid storage. Conclusions Together, our data establish that sHDL nanoparticles are a potential new therapeutic avenue for Niemann–Pick diseases.https://deepblue.lib.umich.edu/bitstream/2027.42/152143/1/12916_2019_Article_1423.pd