729 research outputs found
A Correlation of the Solubility of Water in Hydrocarbons as a Function of Temperature Based on the Corresponding Vapor Pressure of Pure Water
A method of estimating the solubility of water in hydrocarbons as a function of temperature is given here. Hydrocarbons, lacking strong permanent dipoles or traditional hydrogen bonding, do not strongly attract water molecules. The extreme case of a medium bereft of attractive forces is a vacuum, into which water, nonetheless, evaporates. The solubility of water in hydrocarbons at various temperatures can be correlated to the vapor pressure of water at those temperatures. A simple thermodynamic explanation of the dependence on vapor pressure is offered
Airports at Risk: The Impact of Information Sources on Security Decisions
Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport
employees in European Airports across the continent, we analyzed
how both formal and informal sources of security information affect employee's decisions to comply with the security rules and
directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions
while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels
Coffee Stirrers and Drinking Straws as Disposable Spatulas
While metal spatulas are damaged through everyday use and become discolored and corroded by chemical exposure, drinking straws are inexpensive and disposable, reducing the risk of cross contamination during laboratory experiments. Drinking straws are also useful because they come in a variety of sizes; narrow sample containers such as NMR and EPR tubes can easily be filled using small diameter coffee stirrers, while bulk material can be transferred using larger drinking straws.
Several types of drinking straws and coffee stirrers were cut at various angles and the amount of material picked up in a single scoop was massed thirty times. Standard deviations of the thirty measurements per straw indicate that approximately the same amount of material will be scooped each time by the same operator
Nicotinamide complex of silver(III) with expanded coordination number
In strongly alkaline media ([OH-] ≥ 0.12 M), nicotinamide (nica) forms a complex with square-planar Ag(OH)4- [nica] ≥ 0.05 M. The complex decomposes in seconds to nicotinamide N-oxide. The correlation of maximum absorbance of the complex with concentrations of nicotinamide and hydroxide requires that the complex is either the five-coordinate Ag(OH)4(H-1nica)2- or the six-coordinate Ag(OH)5(nica)2-. Comparison with the reactions of Ag(OH)4- with nicotinate ion (nic-) and acetamide under similar conditions indicates that nicotinamide coordinates with Ag(OH)4- by the amido group rather than the nitrogen on the pyridine ring or the amido oxygen. Kinetics of the Ag(III)- nica redox reaction are consistent with direct reaction between nicotinamide and uncoordinated Ag(OH4)-. Oxidation takes place at the pyridine ring, yielding nicotinamide N-oxide. Silver(III) is reduced to monovalent silver
Superfluid Density and Field-Induced Magnetism in Ba(Fe1-xCox)2As2 and Sr(Fe1-xCox)2As2 Measured with Muon Spin Relaxation
We report muon spin rotation (SR) measurements of single crystal
Ba(FeCo)As and Sr(FeCo)As. From
measurements of the magnetic field penetration depth we find that for
optimally- and over-doped samples, varies monotonically
with the superconducting transition temperature T. Within the
superconducting state we observe a positive shift in the muon precession
signal, likely indicating that the applied field induces an internal magnetic
field. The size of the induced field decreases with increasing doping but is
present for all Co concentrations studied.Comment: 7 pages, accepted for publication in Phys. Rev.
Glucitol-core containing gallotannins inhibit the formation of advanced glycation end-products mediated by their antioxidant potential
Glucitol-core containing gallotannins (GCGs) are polyphenols containing galloyl groups attached to a 1,5-anhydro-D-glucitol core, which is uncommon among naturally occurring plant gallotannins. GCGs have only been isolated from maple (Acer) species, including the red maple (Acer rubrum), a medicinal plant which along with the sugar maple (Acer saccharum), are the major sources of the natural sweetener, maple syrup. GCGs are reported to show antioxidant, α-glucosidase inhibitory, and antidiabetic effects, but their antiglycating potential is unknown. Herein, the inhibitory effects of five GCGs (containing 1–4 galloyls) on the formation of advanced glycation end-products (AGEs) were evaluated by MALDI-TOF mass spectroscopy, and BSA–fructose, and G.K. peptide-ribose assays. The GCGs showed superior activities compared to the synthetic antiglycating agent, aminoguanidine (IC50 15.8–151.3 vs. \u3e300 μM) at the early, middle, and late stages of glycation. Circular dichroism data revealed that the GCGs were able to protect the secondary structure of BSA protein from glycation. The GCGs did not inhibit AGE formation by the trapping of reactive carbonyl species, namely, methylglyoxal, but showed free radical scavenging activities in the DPPH assay. The free radical quenching properties of the GCGs were further confirmed by electron paramagnetic resonance spectroscopy using ginnalin A (contains 2 galloyls) as a representative GCG. In addition, this GCG chelated ferrous iron, an oxidative catalyst of AGE formation, supported a potential antioxidant mechanism of antiglycating activity for these polyphenols. Therefore, GCGs should be further investigated for their antidiabetic potential given their antioxidant, α-glucosidase inhibitory, and antiglycating properties
Highly Successful Weight Control by Formerly Obese Adolescents: A Qualitative Test of the Healthy Obsession Model
Abstract Background: the Healthy Obsession Model (HOM) suggests that successful weight controllers must develop a preoccupation with the planning and execution of target behaviors to reach and maintain healthy weights (e.g., controlled eating, consistent selfmonitoring). this model further posits that committed weight controllers will feel substantial anxiety or frustration when lapses occur, which, in turn, will motivate them to reinstate target behaviors. Methods: the present study tested the HOM by examining the perceptions and attitudes of four very successful and four relatively unsuccessful adolescent weight controllers 1 year after completing immersion treatment. We expected that successful weight controllers, more so than unsuccessful weight controllers, would report more elaborate definitions of their healthy obsessions and describe more negative reactions to potential and actual lapses. in-depth interviews were conducted using a version of the scanlan Collaborative interview Method. Results and Conclusions: Reliable coding of the interviews produced results that supported the hypothesis that highly successful weight controllers seem to nurture strong healthy obsessions, including clear definitions of healthy obsessions, heightened commitment based on the emotional impact of excess weight, and negative reactions to lapses. in addition, these adolescent weight controllers seemed motivated by some of the same factors that elite athletes identified in the sport Commitment Model (e.g., emotional and experiential Consequences; social support of Parents, Friends, and Peers; institutional influences; and Valuable Opportunities)
The Passing of Print
This paper argues that ephemera is a key instrument of cultural memory, marking the things intended to be forgotten. This important role means that when ephemera survives, whether accidentally or deliberately, it does so despite itself. These survivals, because they evoke all those other objects that have necessarily been forgotten, can be described as uncanny. The paper is divided into three main sections. The first situates ephemera within an uncanny economy of memory and forgetting. The second focuses on ephemera at a particular historical moment, the industrialization of print in the nineteenth century. This section considers the liminal place of newspapers and periodicals in this period, positioned as both provisional media for information as well as objects of record. The third section introduces a new configuration of technologies – scanners, computers, hard disks, monitors, the various connections between them – and considers the conditions under which born-digital ephemera can linger and return. Through this analysis, the paper concludes by considering digital technologies as an apparatus of memory, setting out what is required if we are not to be doubly haunted by the printed ephemera within the digital archive
Phenol Nitration Induced by an {Fe(NO)\u3csub\u3e2\u3c/sub\u3e}\u3csup\u3e10\u3c/sup\u3e Dinitrosyl Iron Complex
Cellular dinitrosyl iron complexes (DNICs) have long been considered NO carriers. Although other physiological roles of DNICs have been postulated, their chemical functionality outside of NO transfer has not been demonstrated thus far. Here we report the unprecedented dioxygen reactivity of a N-bound {Fe(NO)2}10 DNIC, [Fe(TMEDA)(NO)2] (1). In the presence of O2, 1 becomes a nitrating agent that converts 2,4,-di-tert-butylphenol to 2,4-di-tert-butyl-6-nitrophenol via formation of a putative iron-peroxynitrite [Fe(TMEDA)(NO)(ONOO)] (2) that is stable below −80 °C. Iron K-edge X-ray absorption spectroscopy on 2 supports a five-coordinated metal center with a bound peroxynitrite in a cyclic bidentate fashion. The peroxynitrite ligand of 2 readily decays at increased temperature or under illumination. These results suggest that DNICs could have multiple physiological or deleterious roles, including that of cellular nitrating agents
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