Coping with complexity in home hemodialysis: a fresh perspective on time as a medium of Distributed Cognition

The existing literature on Distributed Cognition (DCog) mostly presents the temporal distribution of cognition in terms of system evolution that happens over time. In this paper, we illustrate how cognition can also be distributed through time in more immediate ways, through four principles we developed while studying how renal patients cope with the complexity of home hemodialysis. These principles are temporal assignments to tasks to aid prospective remembering; temporal arrangement of tasks to help deal with anticipated problems; temporal distribution of a task plan to avoid omission of steps; and temporal re-arrangement of tasks to reduce peak complexity. Like the physical environment, the time continuum is an external medium that can support distributed cognitive processes, serving as a representation for task reminders and allowing actors to organize the order, duration, and spacing of tasks to reduce complexity in cognitive work. These principles can highlight problems and opportunities in the design of socio-technical systems, by explicitly considering time as another medium that can be used to support DCog in short-term activity.     

Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation,characterization and simulated use in an in vitro vessel model

Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer.     

Secondary effects of catalytic diesel particulate filters: conversion of PAHs versus formation of nitro-PAHs

Diesel particulate filters (DPFs) are a promising technology to detoxify diesel exhaust. However, the secondary combustion of diesel soot and associated compounds may also induce the formation of new pollutants. Diesel soot is rated as carcinogenic to humans and also acts as a carrier for a variety of genotoxic compounds such as certain polycyclic aromatic hydrocarbons (PAHs) or nitrated PAHs (nitro-PAHs). Furthermore, diesel exhaust contains considerable amounts of nitric oxide (NO), which can be converted to more powerful nitrating species like nitrogen dioxide (NO2), nitric acid (HNO3), and others. This mix of compounds may support nitration reactions in DPFs. Herein we report effects of two cordierite-based, monolithic, wall-flow DPFs on emissions of genotoxic PAHs and nitro-PAHs and compare these findings with those of a reporter gene bioassay sensitive to aryl hydrocarbons (AHs). Soot combustion was either catalyzed with an iron- or a copper/iron-based fuel additive (fuel-borne catalysts). A heavy duty diesel engine, operated according to the 8-stage ISO 8178/4 C1 cycle, was used as test platform. Emissions of all investigated 4- to 6-ring PAHs were reduced by about 40-90%, including those rated as carcinogenic. Emissions of 1- and 2-nitronaphthalene increased by about 20-100%. Among the 3-ring nitro-PAHs, emissions of 3-nitrophenanthrene decreased by about 30%, whereas 9-nitrophenanthrene and 9-nitroanthracene were found only after DPFs. In case of 4-ring nitro-PAHs, emissions of 3-nitrofluoranthene, 1-nitropyrene, and 4-nitropyrene decreased by about 40-60% with DPFs. Total AH-receptor (AHR) agonist concentrations of diesel exhaust were lowered by 80-90%, when using the iron- and copper-based DPFs. The tested PAHs accounted for < 1% of the total AHR-mediated response, indicating that considerable amounts of other aryl hydrocarbons must be present in filtered and unfiltered exhaust. We conclude that both DPFs detoxified diesel exhaust with respect to total aryl hydrocarbons, including the investigated carcinogenic PAHs, but we also noticed a secondary formation of selected nitro-PAHs. Nitration reactions were found to be stereoselective with a preferential substitution of hydrogen atoms at peri-positions. The stereoisomers obtained are related to combustion chemistry, but differ from those formed upon atmospheric nitration of PAHs.     

Phytostanols and phytosterols distributions in corn kernel

Recently, industry has focused attention on plant matrices rich in phytosterols and phytostanols for their ability to reduce serum cholesterol levels. Therefore, the objective of this study was to examine the phytosterols and phytostanols contents of different fractions (endosperm, pericarp, germ) of corn kernel. The germ fraction contained more oil (24.2–30.7%) than endosperm and pericarp fractions (0.4–1.2%). Endosperm oil had the highest levels of phytostanols and 4,4-dimethylsterols, while pericarp oil had the greatest amounts of 4-desmethylsterols and 4-monomethylsterols. In the oil extracted from three corn kernel fractions sitostanol was the predominant phytostanols (77–87%), followed by campestanol (13–23%). The high percentages of 24–methylencycloartanol and cycloartenol were detected in the endosperm and pericarp parts, respectively. Citrostadienol was detected in corn germ oil as the main component of the 4-monomethylsterols fraction. In different parts of corn kernel, β-sitosterol (62–69%) was the major 4-desmethylsterol, followed by campesterol (11–18%) and stigmasterol (5–13%).     

Constitutive Analysis of the Flow Curve Behavior of an Intermetallic b-solidifying γ-TiAl-based Alloy and Microstructural Characterization of the Deformed State

In the present study, the high-temperature deformation behavior of a cast and subsequently hot-isostatic pressed (HIPed) b-solidifying γ-TiAl-based alloy with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at.%), termed TNM alloy, is investigated. Isothermal compression tests on cylindrical specimens are carried out on a Gleeble 3500 simulator in order to investigate the dynamic recrystallization processes in the three-phase field region (α/α₂+b/b₀+γ?phase field) of the TNM alloy. The deformed microstructure along with the dynamically recrystallized grain size during hot deformation is examined by scanning electron microscopy (SEM). Two phenomenological-type constitutive models are presented and compared to experimental flow stress data.     

Response of catecholamines to manual teat stimulation or machine-milking of Lacaune and Friesen dairy ewes

Increased sympathetic activity, including peripheral release of catecholamines, has been hypothesized to inhibit the milk ejection reflex by blocking the release of oxytocin, by blocking the effect of oxytocin at the mammary gland, or both. We attempted to relate differences in milking characteristics of Lacaune and East Friesen ewes to the degree of sympathetic arousal, responses of catecholamines and oxytocin to machine-milking and to manual teat stimulation followed by milking. Peripheral concentrations of epinephrine, 67 +/- 6 pg/ml for Lacaunes and 57 +/- 5 pg/ml for Friesens, were essentially constant. Peripheral concentrations of norepinephrine averaged 682 +/- 68 pg/ml for Lacaunes and 250 +/- 54 pg/ml for Friesens. Elevated norepinephrine concentrations during the pretreatment period were associated with the inhibition of oxytocin responses. When norepinephrine concentrations during the pretreatment period exceeded 300 pg/ml for Friescens, or were rising and exceeded 700 pg/ml at initiation of the experimental period for Lacaunes, oxytocin release was inhibited. Results from this study clearly showed that basal concentrations of norepinephrine vary with breed of ewes and provided the first direct evidence that increased sympathetic activity can result in central inhibition of the milk ejection reflex.     

Design and Synthesis of α-Diketones. The Cyclobutane-1,2-dione Chromophore: Synthesis,Dienophilic Reactivity and Electronic Properties of Cyclobutenedione and Polycyclic Cyclobutanediones [1]

A new synthesis of cyclobutenedione (1) is described. It is found that the tricyclic cyclobutanedione 3 splits into 1 and cyclopentadiene if subjected to flash pyrolysis conditions. The dienophilic reactivity of 1 allows the construction of various polycyclic cyclobutanediones, such as 3–5 and 12–14. Other new polycyclic diones, like 9–11, 15 and 16 are prepared by means of the acyloin condensation. The low stereoselectivity of 1 with cyclopentadiene is compared with the selectivity of other cyclobutenes, and the results are placed in the context of secondary interactions and steric hindrance. The unusual colour properties of these diones, from colourless 1 to blue 6 are investigated by means of photoelectron spectroscopic measurements and semi-empirical calculations (MNDO, HAM/3, CNDO/S-CI).