To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Cereals are of major importance in human and animal nutrition, and the mycotoxin content is of great health and economic concern for the food sector and consumers. In Europe, Fusarium graminearum (FG) is the prevalent Fusarium species leading to Fusarium head blight on small grain cereals and contamination of grains by its main mycotoxin deoxynivalenol (DON). The present study assessed the costs of preventive agronomic measures to reduce the risk of DON contamination in wheat besides the use of fungicides. The abatement costs were calculated by linking actual data on wheat production costs and profits with assessments of DON contents based on results of the forecast model FusaProg for the period 2005–2011. Analysis revealed that ploughing was a relatively efficient measure to reduce DON risk compared with modifying crop rotation or growing a more FG-resistant wheat variety. Given a threshold value of 1·25 mg DON/kg wheat, a reduction of 0·1 mg DON was related to additional production costs of at least 2·5%. These economic findings are of relevance for farmers and policy makers in order to define sustainable production systems enabling both a high level of food safety and reducing the use of plant protection products.
This chapter reviews the current knowledge of the molecular mechanisms controlling embryonic lung development in animal models from the initial specification of a small number of respiratory progenitor cells in the ventral foregut endoderm through the formation of the mature adult lung with regionally specialized epithelial, interstitial, and vascular compartments. In the second half of this chapter we introduce induced pluripotent stem cells (iPSCs) as a compelling new platform to study human lung biology at developmental time-points previously inaccessible to researchers. iPSCs offer the potential to generate functional lung tissue in vitro by translating the knowledge gained from studying respiratory system development in different animal models where many of the signaling pathways or airway branching mechanisms are evolutionarily conserved. There are many exciting possible applications of iPSC-derived lung tissue, including the ability to model human lung disease, screen novel drug therapies, and ultimately generate functional, transplantable lung cells or 3-D tissues for those suffering from one of the many forms of end-stage lung disease.
The effect of a nanometer confinement on the molecular dynamics of poly(methyl phenyl siloxane) (PMPS) was studied by dielectric spectroscopy (DS), temperature modulated DSC (TMDSC) and neutron scattering (NS). DS and TMDSC experiments show that for PMPS in 7.5 nm pores the molecular dynamics is faster than in the bulk which originates from an inherent length scale of the underlying molecular motions. At a pore size of 5 nm the temperature dependence of the relaxation times changes from a Vogel / Fulcher / Tammann like behavior to an Arrhenius one. At the same pore size Δcp vanishes. These results give strong evidence that the glass transition has to be characterized by an inherent length scale of the relevant molecular motions. Quasielastic neutron scattering experiments reveal a strong change even in the microscopic dynamic.
The technique for ultra rapid opioid detoxification is designed to shorten the detoxification period by precipitating withdrawal by the administration of opioid antagonists such as naloxone or naltrexone. This procedure is performed under deep sedation or general anaesthesia to ensure that the patient does not consciously experience the acute withdrawal phase. This strategy has aroused controversy regarding the risk of sedation or anaesthesia in this situation. In the present study, ultra rapid opioid detoxification was carried out in 12 opiate-addicted patients by infusion of naloxone 4 mg for a period of 5 h using controlled ventilation during general anaesthesia, induced and maintained with midazolam, propofol and atracurium. Invasive cardiovascular and respiratory monitoring was performed, and withdrawal signs were evaluated using a graduated scale. Anaesthesia was maintained for another hour after the completion of the naloxone infusion. The validity of this anaesthesia protocol was confirmed by the relative lack of change in the patients’ haemodynamic values associated with mild signs of withdrawal.
The mechanism causing the CuPtB-type ordering of InGaP grown lattice matched to GaAs was investigated by in-situ reflectance anisotropy spectroscopy (RAS/RDS). Experiments were performed during InGaP growth in metal-organic vapour phase epitaxy (MOVPE). From the experiments it can be concluded that bulk ordering only occurs when InGaP growth is performed under phosphorus-rich (2×1)-like surface conditions. Bulk ordering completely disappears under growth conditions which cause a less-phosphorus-rich (2×4)-like surface dimer configuration.
Epitaxial InP(100)-films were prepared with TBP (tertiarybutylphosphine) and TMIn (trimethylindium) as precursors in a commercial MOCVD reactor. During growth, the V-III-ratio and TBP partial pressure were varied between 50 and 1 and possible changes of the surface structure monitored with the corresponding RAS (reflectance anisotropy spectroscopy) signal based on a correlation established with corresponding LEED measurements. Bulk properties of these films were investigated ex-situ with photoluminescence at 2 K, showing no noticeable difference between the samples. The MOCVD apparatus was modified to facilitate transfer of the sample from the MOCVD environment to UIHV in less than 20 seconds (to the 10−9 mbar range). After transfer, the same RA spectrum was recovered also in the critical case of the P-rich, as-grown surface. A corresponding Auger electron spectrum (AES) did not show any trace of contamination. Furthermore, the surface structure was investigated with LEED and STM. The LEED picture shows a clear (2×l)-pattern with a weak twofold symmetry along the  direction, STM pictures revealed a disordered surface terminated by P-dimers
Surface science analysis can be utilized for improving the preparation of hetero-interfaces. Epitaxial InP(100)-films were prepared with TBP (tertiarybutylphosphine) and TMin (trimethylindium) as precursors in a commercial MOCVD apparatus. With a new type of transfer system the sample is shifted from the MOCVD apparatus to a UHV chamber within 20 s. A description of the new transfer system is given. RAS (reflection anisotropy spectroscopy) is carried out in the MOCVD and UHV environments. It shows whether the InP(100) surface corresponds to the (2×1) or (2×4) reconstruction or whether it is oxidized. For the first time contamination-free transfer of the (2×1) reconstructed, P-rich InP(100) surface is achieved.
A critical element of decision making is the timing of choices political actors make; often when a decision is made is as critical as the decision itself. We posit a dynamic model of strategic position announcement based on signaling theories of legislative politics. We suggest that members who receive clear signals from constituents, interest groups, and policy leaders will announce their positions earlier. Those with conflicting signals will seek more information, delaying their announcement. We test several expectations by examining data on when members of the House of Representatives announced their positions on the North American Free Trade Agreement. We also contrast the timing model with a vote model, and find that there are meaningful differences between the factors influencing the timing of position announcements and vote choice. Our research allows analysts to interpret the process leading up to the House action and the end state of that process.
A low dose rate evaluation of several scintillators and wavelength shifters of interest to the CEBAF program was performed with a 60Co line source to a total dose of 160 Gray at a rate of 0.5 Gy/hr in a slowly flowing oxygen atmosphere. The samples included the following: (1) a 2 meter piece of Bicron BC412 scintillator being extensively used in the CEBAF Large Acceptance Spectrometer, (2) a 1 meter long piece of green scintillator doped with a uniquely fast green fluor (G2), (3) wavelength shifting fiber dopedalso with G2, and (4) grooved acrylic-based scintillator that is readout with the WLS fiber. The data indicates that the BC412 shows no loss in intrinsic light output, but does have an attenuation loss amounting to 10% at 1 meter and 16% at 2 meters. The fast green scintillator (and fibers) showed no damage. When read out by WLS fibers, the acrylic scintillator displayed a loss in intrinsic light output, but no change in attenuation.
Reflectance anisotropy spectroscopy (RAS) is presented as real time analytical tool for metalorganic vapourphase epitaxy (MOVPE) of III-V-semiconductors. This optical method derives its surface sensitivity from the anisotropy of surface structures. It is shown that it is possible to monitor with RAS the oxide desorption from the substrate and that the substrate surface conditions thereafter, still in the pregrowth stage, can be correlated with certain reconstructions of the (001)-surfaces of InP and GaAs. The latter is possible through simultaneous RAS and RHEED measurements during MBE (molecular beam epitaxy) or MOMBE (metalorganic molecular beam epitaxy). Characteristic spectral features are also observed for other binary or ternary III-V-semiconductors. Time resolved measurements during growth give monolayer resolution for the growth rate in the case of GaAs. In the study of heterointerface growth exchange reactions between As and P together with their corresponding reaction time constants can be monitored and conclusions for the epitaxial growth procedure can be drawn.
Real time observations of the YBa2Cu3O7-δ (123) melting process by high temperature XRD and optical microscopy reveal a reaction sequence which does not correspond well with the literature. CO2 gas, present in the air, reacts with 123 to produce the Y2CU2O5 phase. This reaction begins well below 800°C and persists up to 970°C when BaCuO2 begins to form. The previously unreported BaCuO2 reaction occurs in either air or oxygen and this phase grows at the expense of the 123 until both rapidly disappear at 1050°C with the appearance of Y2B2CuO5 (211), Formation of Y2O3 from the 211 melt occurs more slowly, beginning at 1150°C. Dynamic 00ℓ orientation has been observed at 950°C upon cooling from the melt. The orientationa) growth is believed to be a surface tension dependent, liquid assisted sintering reaction.
Email your librarian or administrator to recommend adding this to your organisation's collection.