High pressure/thermal treatment effects on the texture of beef muscle

The effects of high pressure (to 800 MPa) applied at different temperatures (20-70 degreesC) for 20 min on beef post-rigor longissimus dorsi texture were studied. Texture profile analysis showed that when heated at ambient pressure there was the expected increase in hardness with increasing temperature and when pressure was applied at room temperature there was again the expected increase in hardness with increasing pressure. Similar results to those found at ambient temperature were found when pressure was applied at 40 degreesC. However, at higher temperatures, 60 and 70 degreesC it was found that pressures of 200 MPa caused large and significant decreases in hardness. The results found for hardness were mirrored by those for gumminess and chewiness. To further understand the changes in texture observed, intact beef longissimus dorsi samples and extracted myofibrils were both subjected to differential scanning calorimetry after being subjected to the same pressure/temperature regimes. As expected collagen was reasonably inert to pressure and only at temperatures of 60-70 degreesC was it denatured/unfolded. However, myosin was relatively easily unfolded by both pressure and temperature and when pressure denatured a new and modified structure was formed of low thermal stability. Although this new structure had low thermal stability at ambient pressure it still formed in both the meat and myofibrils when pressure was applied at 60 degreesC. It seems unlikely that structurally induced changes can be a major cause of the significant loss of hardness observed when beef is treated at high temperature (60-70 degreesC) and 200 MPa and it is suggested that accelerated proteolysis under these conditions is the major cause. (C) 2004 Elsevier Ltd. All rights reserved.

Flavor characterization of sugar-added pennywort (Centella asiatica L.) juices treated with ultra-high pressure and thermal processes

The flavor characteristics of pennywort juices with added sugar treated by ultra-high pressure, pasteurization, and sterilization were investigated using solid phase microextraction combined with gas chromatography-mass spectrometry. It was found that sesquiterpene hydrocarbons comprised the major class of volatile components present and the juices had a characteristic aroma due to the presence of volatiles including beta-caryophyllene and humulene and alpha-copaene. In comparison with heated juices, HPP-treated samples could retain more volatile compounds such as linalool and geraniol similar to those present in fresh juice, whereas some volatiles such as alpha-terpinene and ketone class were apparently formed by thermal treatment. All processing operations produced juice that was not significantly different in the concentration of total volatiles. Practical Application: Pennywort juice is considered a nutraceutical drink for health benefits. Therefore, to preserve all aroma and active components in this juice, a nonthermal process such as ultra-high pressure should be a more appropriate technique for retention of its nutritive values than pasteurization and sterilization.

A differential thermal expansion approach to crystal structure determination from powder diffraction data

Differential thermal expansion over the range 90-210 K has been applied successfully to determine the crystal structure of chlorothiazide from synchrotron powder diffraction data using direct methods. Key to the success of the approach is the use of a multi-data-set Pawley refinement to extract a set of reflection intensities that is more 'single-crystal-like' than those extracted from a single data set. The improvement in reflection intensity estimates is quantified by comparison with reference single-crystal intensities. (C) 2008 International Union of Crystallography Printed in Singapore - all rights reserved

Integrated optics for nulling interferometry in the thermal infrared

Modal filtering is based on the capability of single-mode waveguides to transmit only one complex amplitude function to eliminate virtually any perturbation of the interfering wavefronts, thus making very high rejection ratios possible in a nulling interferometer. In the present paper we focus on the progress of Integrated Optics in the thermal infrared [6-20 mu m] range, one of the two candidate technologies for the fabrication of Modal Filters, together with fiber optics. In conclusion of the European Space Agency's (ESA) "Integrated Optics for Darwin" activity, etched layers of clialcogenide material deposited on chalcogenide glass substrates was selected among four candidates as the technology with the best potential to simultaneously meet the filtering efficiency, absolute and spectral transmission, and beam coupling requirements. ESA's new "Integrated Optics" activity started at mid-2007 with the purpose of improving the technology until compliant prototypes can be manufactured and validated, expectedly by the end of 2009. The present paper aims at introducing the project and the components requirements and functions. The selected materials and preliminary designs, as well as the experimental validation logic and test benches are presented. More details are provided on the progress of the main technology: vacuum deposition in the co-evaporation mode and subsequent etching of chalcogenide layers. In addition., preliminary investigations of an alternative technology based on burying a chalcogenide optical fiber core into a chalcogenide substrate are presented. Specific developments of anti-reflective solutions designed for the mitigation of Fresnel losses at the input and output surface of the components are also introduced.

An optical force-feedback microphone for sensing biophotonics related photoacoustic and photo-thermal phenomena [poster]

We discuss a novel approach to the development of an ultrasonic optical force-feedback measurement microphone suitable for observing biophotonic related photoacoustic and photothermal phenomena at high modulation frequencies and spatial resolution.

Twentieth century secular decrease in the atmospheric potential gradient

Current flowing in the global atmospheric electrical circuit (AEC) substantially decreased during the twentieth century. Fair-weather potential gradient (PG) observations in Scotland and Shetland show a previously unreported annual decline from 1920 to 1980, when the measurements ceased. A 25% reduction in PG occurred in Scotland 1920–50, with the maximum decline during the winter months. This is quantitatively explained by a decrease in cosmic rays (CR) increasing the thunderstorm-electrosphere coupling resistance, reducing the ionospheric potential VI. Independent measurements of VI also suggest a reduction of 27% from 1920–50. The secular decrease will influence fair weather atmospheric electrical parameters, including ion concentrations and aerosol electrification. Between 1920–50, the PG showed a negative correlation with global temperature, despite the positive correlation found recently between surface temperature and VI. The 1980s stabilisation in VI may arise from compensation of the continuing CR-induced decline by increases in global temperature and convective electrification.

Structures and negative thermal expansion properties of the one-dimensional cyanides, CuCN, AgCN and AuCN

The behaviour of the lattice parameters of HTCuCN (high-temperature form), AgCN and AuCN have been investigated as a function of temperature over the temperature range 90–490 K. All materials show one-dimensional negative thermal expansion (NTE) along the ––(M––CN)–– chain direction c (ac(HT-CuCN) ¼32.1 10–6 K1, ac(AgCN)¼23.910–6 K1 and ac(AuCN) ¼9.3106 K1 over the temperature range 90–490 K). The origin of this behaviour has been studied using RMC modelling of Bragg and total neutron diffraction data from AgCN and AuCN at 10 and 300 K. These analyses yield details of the local motions within the chains responsible for NTE. The low-temperature form of CuCN, LT-CuCN, has been studied using single-crystal X-ray diffraction. In this form of CuCN, wavelike distortions of the ––(Cu––CN)–– chains occur in the static structure, which are reminiscent of the motions seen in the RMC modelling of AgCN and AuCN, which are responsible for the NTE behaviour.

Thermal decomposition of potassium hexanitronickelate(II) hydrate

The thermal decomposition of the complex K-4[Ni(NO2)6]center dot H2O has been investigated over the temperature range 25-600 degrees C by a combination of infrared spectroscopy, powder X-ray diffraction, FAB-mass spectrometry and elemental analysis. The first stage of reaction is loss of water and isomerisation of one of the coordinated nitro groups to form the complex K-4 [Ni(NO2)(4) (ONO)]center dot NO2. At temperatures around 200 degrees C the remaining nitro groups within the complex isomerise to the chelating nitrite form and this process acts as a precursor to the loss of NO2 gas at temperatures above 270 degrees C. The product, which is stable up to 600 degrees C, is the complex K-4[Ni(ONO)(4)]center dot NO2, where the nickel atom is formally in the +1 oxidation state. (c) 2005 Elsevier B.V. All rights reserved.

Occupants' adaptive responses and perception of thermal environment in naturally conditioned university classrooms

A year-long field study of the thermal environment in university classrooms was conducted from March 2005 to May 2006 in Chongqing, China. This paper presents the occupants’ thermal sensation votes and discusses the occupants’ adaptive response and perception of the thermal environment in a naturally conditioned space. Comparisons between the Actual Mean Vote (AMV) and Predicted Mean Vote (PMV) have been made as well as between the Actual Percentage of Dissatisfied (APD) and Predicted Percentage of Dissatisfied (PPD). The adaptive thermal comfort zone for the naturally conditioned space for Chongqing, which has hot summer and cold winter climatic characteristics, has been proposed based on the field study results. The Chongqing adaptive comfort range is broader than that of the ASHRAE Standard 55-2004 in general, but in the extreme cold and hot months, it is narrower. The thermal conditions in classrooms in Chongqing in summer and winter are severe. Behavioural adaptation such as changing clothing, adjusting indoor air velocity, taking hot/cold drinks, etc., as well as psychological adaptation, has played a role in adapting to the thermal environment.

Physiological expression of human thermal comfort to indoor operative temperature in the non-HVAC environment

A physiological experiment was carried out in a naturally ventilated, non-HVAC indoor environment of a spacious experimental room. More than 300 healthy university students volunteered for this study. The purpose of the study was to investigate the human physiological indicators which could be used to characterise the indoor operative temperature changes in a building and their impact on human thermal comfort based on the different climatic characteristics people would experience in Chongqing, China. The study found that sensory nerve conduction velocity (SCV) could objectively provide a good indicator for assessment of the human response to changes in indoor operative temperatures in a naturally ventilated situation. The results showed that with the changes in the indoor operative temperatures, the changing trend in the nerve conduction velocity was basically the same as that of the skin temperature at the sensory nerve measuring segment (Tskin(scv)). There was good coherent consistency among the factors: indoor operative temperature, SCV and Tskin(scv) in a certain indoor operative temperature range. Through self-adaptation and self-feedback regulation, the human physiological indicators would produce certain adaptive changes to deal with the changes in indoor operative temperature. The findings of this study should provide the baseline data to inform guidelines for the development of thermal environment-related standards that could contribute to efficient use of energy in buildings in China.

Emulating AOGCM results using simple climate models

Three simple climate models (SCMs) are calibrated using simulations from atmosphere ocean general circulation models (AOGCMs). In addition to using two conventional SCMs, results from a third simpler model developed specifically for this study are obtained. An easy to implement and comprehensive iterative procedure is applied that optimises the SCM emulation of global-mean surface temperature and total ocean heat content, and, if available in the SCM, of surface temperature over land, over the ocean and in both hemispheres, and of the global-mean ocean temperature profile. The method gives best-fit estimates as well as uncertainty intervals for the different SCM parameters. For the calibration, AOGCM simulations with two different types of forcing scenarios are used: pulse forcing simulations performed with 2 AOGCMs and gradually changing forcing simulations from 15 AOGCMs obtained within the framework of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. The method is found to work well. For all possible combinations of SCMs and AOGCMs the emulation of AOGCM results could be improved. The obtained SCM parameters depend both on the AOGCM data and the type of forcing scenario. SCMs with a poor representation of the atmosphere thermal inertia are better able to emulate AOGCM results from gradually changing forcing than from pulse forcing simulations. Correct simultaneous emulation of both atmospheric temperatures and the ocean temperature profile by the SCMs strongly depends on the representation of the temperature gradient between the atmosphere and the mixed layer. Introducing climate sensitivities that are dependent on the forcing mechanism in the SCMs allows the emulation of AOGCM responses to carbon dioxide and solar insolation forcings equally well. Also, some SCM parameters are found to be very insensitive to the fitting, and the reduction of their uncertainty through the fitting procedure is only marginal, while other parameters change considerably. The very simple SCM is found to reproduce the AOGCM results as well as the other two comparably more sophisticated SCMs.

Longitudinal investigation of the faecal microbiota of healthy full-term infants using fluorescence in situ hybridization and denaturing gradient gel electrophoresis.

From birth onwards, the gastrointestinal (GI) tract of infants progressively acquires a complex range of micro-organisms. It is thought that by 2 years of age the GI microbial population has stabilized. Within the developmental period of the infant GI microbiota, weaning is considered to be most critical, as the infant switches from a milk-based diet (breast and/or formula) to a variety of food components. Longitudinal analysis of the biological succession of the infant GI/faecal microbiota is lacking. In this study, faecal samples were obtained regularly from 14 infants from 1 month to 18 months of age. Seven of the infants (including a set of twins) were exclusively breast-fed and seven were exclusively formula-fed prior to weaning, with 175 and 154 faecal samples, respectively, obtained from each group. Diversity and dynamics of the infant faecal microbiota were analysed by using fluorescence in situ hybridization and denaturing gradient gel electrophoresis. Overall, the data demonstrated large inter- and intra-individual differences in the faecal microbiological profiles during the study period. However, the infant faecal microbiota merged with time towards a climax community within and between feeding groups. Data from the twins showed the highest degree of similarity both quantitatively and qualitatively. Inter-individual variation was evident within the infant faecal microbiota and its development, even within exclusively formula-fed infants receiving the same diet. These data can be of help to future clinical trials (e.g. targeted weaning products) to organize protocols and obtain a more accurate outline of the changes and dynamics of the infant GI microbiota.

Integrated optics for nulling interferometry in the thermal infrared: progress and recent achievements

The search for Earth-like exoplanets, orbiting in the habitable zone of stars other than our Sun and showing biological activity, is one of the most exciting and challenging quests of the present time. Nulling interferometry from space, in the thermal infrared, appears as a promising candidate technique for the task of directly observing extra-solar planets. It has been studied for about 10 years by ESA and NASA in the framework of the Darwin and TPF-I missions respectively. Nevertheless, nulling interferometry in the thermal infrared remains a technological challenge at several levels. Among them, the development of the "modal filter" function is mandatory for the filtering of the wavefronts in adequacy with the objective of rejecting the central star flux to an efficiency of about 105. Modal filtering takes benefit of the capability of single-mode waveguides to transmit a single amplitude function, to eliminate virtually any perturbation of the interfering wavefronts, thus making very high rejection ratios possible. The modal filter may either be based on single-mode Integrated Optics (IO) and/or Fiber Optics. In this paper, we focus on IO, and more specifically on the progress of the on-going "Integrated Optics" activity of the European Space Agency.