Rapid and quantitative determination of hexanal in cooked muscle foods

A simple and rapid method was developed to quantify hexanaJ in cooked muscle foods. The method involves extraction of the 2,4-dinitrophenylhydrazones of carbonyls with hexane and their separation by reversed-phased high performance liquid chromatography. The method compared well with the classical thiobarbituric acid test. The method was successfully used to quantify hexana) in cooked beef and pork burgers during storage at 4 °C for up to 1 week as well as in cooked turkey burgers after diet supplementation with vitamin E. After 7 days' storage at 4 °C, the contents of hexanal increased from 0.71 to 22.50 μ.mol/kg in beef burgers, from 0.89 to 32.7S μmol / kg in pork burgers and from 1.31 to S2.16 μmol / kg in turkey burgers (20 mg vitamin E per kg feed). Supplementation of turkey feeds with 600 mg Yitamin E per kg resulted in a 24% reduction in hexanal content in cooked turkey burgers after storage for 7 days at 4 °C, compared to the control (unsupplemented) group

INSPACE CHEMICAL PROPULSION SYSTEMS AT NASA's MARSHALL SPACE FLIGHT CENTER: HERITAGE AND CAPABILITIES

NASA s Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V rocket and the Space Shuttle external tank, solid rocket boosters, and main engines. This paper highlights a lesser known but very rich side of MSFC-its heritage in the development of in-space chemical propulsion systems and its current capabilities for spacecraft propulsion system development and chemical propulsion research. The historical narrative describes the flight development activities associated with upper stage main propulsion systems such as the Saturn S-IVB as well as orbital maneuvering and reaction control systems such as the S-IVB auxiliary propulsion system, the Skylab thruster attitude control system, and many more recent activities such as Chandra, the Demonstration of Automated Rendezvous Technology (DART), X-37, the X-38 de-orbit propulsion system, the Interim Control Module, the US Propulsion Module, and multiple technology development activities. This paper also highlights MSFC s advanced chemical propulsion research capabilities, including an overview of the center s Propulsion Systems Department and ongoing activities. The authors highlight near-term and long-term technology challenges to which MSFC research and system development competencies are relevant. This paper concludes by assessing the value of the full range of aforementioned activities, strengths, and capabilities in light of NASA s exploration missions

Tablet PCs in schools: Case study report: A report for Becta by the Open University

The publication provides an analysis of twelve case studies involving schools in England that were using Tablet PCs. The analysis is complemented by brief individual reports describing aspects of how each of these schools was using Tablet PCs

Survival of the d-wave superconducting state near the edge of antiferromagnetism in the cuprate phase diagram

In the cuprate superconductor $YBa_2Cu_3O_{6+x}$, hole doping in the $CuO_2$ layers is controlled by both oxygen content and the degree of oxygen-ordering. At the composition $\rm YBa_2Cu_3O_{6.35}$, the ordering can occur at room temperature, thereby tuning the hole doping so that the superconducting critical temperature gradually rises from zero to 20 K. Here we exploit this to study the c-axis penetration depth as a function of temperature and doping. The temperature dependence shows the d-wave superconductor surviving to very low doping, with no sign of another ordered phase interfering with the nodal quasiparticles. The only apparent doping dependence is a smooth decline of superfluid density as Tc decreases.Comment: 4 pages, 3 figure

Beyond the Dipole Approximation: Angular-Distribution Effects in the 1s Photoemission from Small Molecules

Over the past two decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Recent experiments on the 1s inner shells of small molecules at relatively low photon energies (⩽ 1000 eV) show strong nondipole effects. They are significant and measurable at energies close to threshold, in conflict with a common assumption that the dipole approximation is valid for photon energies below 1 keV

Large Nondipole Effects in the Angular Distributions of K-Shell Photoelectrons from Molecular Nitrogen

Measurements of angular distributions of K-shell electrons photoejected from molecular nitrogen are reported which reveal large deviations at relatively low photon energies ( ħω≤500eV) from emission patterns anticipated from the dipole approximation to interactions between radiation and matter. A concomitant theoretical analysis incorporating the effects of electromagnetic retardation attributes the observed large nondipole behaviors in N2 to bond-length-dependent terms in the E1⊗(E2,M1) photoelectron emission amplitudes which are indicative of a potentially universal nondipole behavior in molecular photoionization

Nondipole Resonant X-ray-Raman Spectroscopy: Polarized Inelastic Scattering at the K Edge of Cl2

Experimental and theoretical studies are reported on the inelastic (Raman) scattering of wavelength-selected polarized x rays from the K edge of gas-phase chlorine molecules. The polarized emission spectra exhibit prominent nondipole features consequent of phase variations of the incident and emitted radiation over molecular dimensions, as predicted by the Kramers-Heisenberg scattering formalism. Issues pursuant to the detection of core-hole localization by resonant Raman scattering from homonuclear diatomic molecules are critically examined. [S0031-9007(97)03486-8

Teaching word recognition to children with severe learning difficulties: an exploratory comparison of teaching methods

Background: Some children with severe learning difficulties fail to begin word recognition. For these children there is a need for an effective and appropriate pedagogy. However, conflicting advice can be found regarding this derived from teaching approaches that are not based on a shared understanding of how reading develops or the skills that the non-reader needs to master. Purpose: In this research, three techniques for teaching word recognition in this context are described and compared: (1) the handle technique, (2) morphing method and (3) word alone. It also discusses whether it is appropriate for such small-scale research to influence pedagogy. Programme description: The handle technique uses an abstract mnemonic cue used to teach word recognition, and previous research indicates it is more successful than the presentation of words alone. The morphing method transforms a word into a photographic picture and a previous study suggested that it might also be more effective that presenting words alone. Sample: Six children between 11 and 13 years of age were selected. The criterion for selection was being unable to recognise any words from the British Ability Scales Reading Test. All the children attended a school for children with severe learning difficulties. Design and methods: A three-condition related design was used. The order in which the conditions were presented was counterbalanced and each child was taught 12 words, four words in each experimental condition. The children encountered each of the three methods and overall each word was taught via each method. Within conditions (teaching methods), the presentation of words was randomised. The number of words that the children could read (without cues) before each session was recorded, following the presentation of the uncued words in a random order. The difference in the number of words recognised between the three conditions was considered using a non-parametric statistical analysis. Results: The results suggest that the handle approach might be a more effective method of teaching word recognition. Conclusion: Research in this area is necessarily small in scale. However, it is ongoing and cumulative, and can give insights into potentially beneficial changes in classroom practice

Reply to Comment on ‘Nondipole Resonant X-ray-Raman Spectroscopy: Polarized Inelastic Scattering at the K Edge of Cl2,’

Mills et al. Reply: In their Comment on our Letter [1], Gel’mukhanov and Ågren [2] reiterate recent assertions [3] based on their earlier theoretical studies [4]. The primary purpose of their Comment is apparently to refute our stated conclusion that core-excited-state localization/ delocalization mechanisms are irrelevant to interpretations of reported Raman scattering experiments on homonuclear diatomic molecules