Design and Performance Simulations of the Bunch Compressor for the APS LEUTL FEL

A magnetic bunch compressor has been designed and is being commissioned for the APS linac to provide higher peak current for the LEUTL FEL. Of primary concern is control of emittance growth due to coherent synchrotron radiation (CSR). In addition, tolerances must be carefully evaluated in order to choose the most stable operating conditions and ensure that the system can meet operational goals. The computer code ELEGANT was used to design the bunch compressor, set tolerances, and simulate likely performance. This 6-D code includes a fast, simple simulation of CSR effects as well as longitudinal and transverse wakefields. It also is believed to be unique in allowing optimization of actual tracking results, such as bunch length, energy spread, and emittance. Automated setup and analysis of matching and tolerance simulations allowed consideration of numerous configurations without excessive effort. This permitted choosing configurations that reduce sensitivity to errors. Simulations indicate that emittance growth should be tolerable for up to 600 A peak current, for which the normalized emittance will increase from 5 to about 6.8 pi-um. The simulations also provide predictions of emittance variation with chicance parameters, which we hope to verify experimentally. * Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.Comment: LINAC2000 THB16 3 pages 3 figure

A Highly Flexible Bunch Compressor for the APS LEUTL FEL

The LEUTL FEL at the APS has achieved gain at 530 nm with peak beam current \~100 A. In an effort to push to 120 nm and beyond, we have designed and are commissioning a bunch compressor to increase the peak current to 600 A or more. The bunch compressor uses a four-dipole chicane at an energy of 100 to 210 MeV. To provide options for control of emittance growth due to coherent synchrotron radiation (CSR), the chicane has variable R56. The central pair of dipoles is movable, accommodating variable R56 with less concern about emittance dilution from nonuniformity of the dipole field. The symmetry of the chicane is also variable via longitudinal motion of the final dipole, which is predicted to have an effect on emittance growth. Following the chicane, a three-screen emittance measurement system should permit resolution of the difference in emittance growth between various chicane configurations. A vertical bending magnet analysis line is present to permit imaging of correlations between transverse and energy coordinates. This paper reviews the features and expected performance of the chicane. A companion paper discusses the physics design in detail. Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.Comment: LINAC2000 THC05 3 pages 1 figur

Use of Coherent Transition Radiation to Set Up the APS RF Thermionic Gun to Produce High-Brightness Beams for SASE FEL Experiments

We describe use of the Advanced Photon Source (APS) rf thermionic gun, alpha magnet beamline, and linac to produce a stable high-brightness beam in excess of 100 amperes peak current with normalized emittance of 10 pi mm-mrad. To obtain peak currents greater than 100 amperes, the rf gun system must be tuned to produce a FWHM bunch length on the order of 350 fs. Bunch lengths this short are measured using coherent transition radiation (CTR) produced when the rf gun beam, accelerated to 40 MeV, strikes a metal foil. The CTR is detected using a Golay detector attached to one arm of a Michelson interferometer. The alpha magnet current and gun rf phase are adjusted so as to maximize the CTR signal at the Golay detector, which corresponds to the minimum bunch length. The interferometer is used to measure the autocorrelation of the CTR radiation. The minimum phase approximation is used to derive the bunch profile from the autocorrelation. The high-brightness beam is accelerated to 217 MeV and used to produce SASE in five APS undulators installed in the Low- Energy Undulator Test Line (LEUTL) experiment hall. Initial optical measurements showed a gain length of 1.3 m at 530 nm. * Work supported by U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.Comment: LINAC2000 MOB17 3 pages 8 figure

Introducing Toxicology into the Biochemistry Curricula: Using Cytochrome c (Cytc) Functionalities as a Model

The electron transport chain (ETC) is a keystone topic of all biochemistry courses at the undergraduate level. Many ETC components, especially cytochrome c (Cytc), are also important to the field of toxicology. Unfortunately, many primarily undergraduate institutions (PUIs) are unable to offer dedicated toxicology courses and laboratories due to faculty expertise and/or enrollment requirements. In an effort to provide chemistry and biology undergraduates with toxicology perspective and experience, I have integrated Cytc toxicology, and its role in apoptosis, into my Biochemistry I and II curriculum. This approach fulfills two goals: 1) integration of toxicology concepts into the biochemistry curriculum and 2) validation of fundamental biochemistry principles through demonstration of “real world” relevance in the field of toxicology. These concepts include Cytc “leakage” to the cytosol, activation of the apoptotic signaling cascade, Cytc/membrane interactions, the modulation of apoptosis by Cytc phosphorylation, and chemical/environmental toxicants that activate this function of Cytc. I conclude with a discussion of student assessment in relation to this methodology. Overall, these materials provide biochemistry instructors with a primer to introduce toxicology concepts in the greater biochemistry curricula or a means for toxicology faculty to validate key biochemistry principles within their classroom

‘Fixed-axis’ magnetic orientation by an amphibian: non-shoreward-directed compass orientation, misdirected homing or positioning a magnetite-based map detector in a consistent alignment relative to the magnetic field?

Experiments were carried out to investigate the earlier prediction that prolonged exposure to long-wavelength (>500 nm) light would eliminate homing orientation by male Eastern red-spotted newts Notophthalmus viridescens. As in previous experiments, controls held in outdoor tanks under natural lighting conditions and tested in a visually uniform indoor arena under full-spectrum light were homeward oriented. As predicted, however, newts held under long-wavelength light and tested under either full-spectrum or long-wavelength light (>500 nm) failed to show consistent homeward orientation. The newts also did not orient with respect to the shore directions in the outdoor tanks in which they were held prior to testing. Unexpectedly, however, the newts exhibited bimodal orientation along a more-or-less `fixed' north-northeast—south-southwest magnetic axis. The orientation exhibited by newts tested under full-spectrum light was indistinguishable from that of newts tested under long-wavelength light, although these two wavelength conditions have previously been shown to differentially affect both shoreward compass orientation and homing orientation. To investigate the possibility that the `fixed-axis' response of the newts was mediated by a magnetoreception mechanism involving single-domain particles of magnetite, natural remanent magnetism (NRM) was measured from a subset of the newts. The distribution of NRM alignments with respect to the head—body axis of the newts was indistinguishable from random. Furthermore, there was no consistent relationship between the NRM of individual newts and their directional response in the overall sample. However, under full-spectrum, but not long-wavelength, light, the alignment of the NRM when the newts reached the 20 cm radius criterion circle in the indoor testing arena (estimated by adding the NRM alignment measured from each newt to its magnetic bearing) was non-randomly distributed. These findings are consistent with the earlier suggestion that homing newts use the light-dependent magnetic compass to align a magnetite-based `map detector' when obtaining the precise measurements necessary to derive map information from the magnetic field. However, aligning the putative map detector does not explain the fixed-axis response of newts tested under long-wavelength light. Preliminary evidence suggests that, in the absence of reliable directional information from the magnetic compass (caused by the 90° rotation of the response of the magnetic compass under long-wavelength light), newts may resort to a systematic sampling strategy to identify alignment(s) of the map detector that yields reliable magnetic field measurements

Trends in beliefs about the harmfulness and use of stop-smoking medications and smokeless tobacco products among cigarettes smokers: Findings from the ITC four-country survey

BACKGROUND: Evidence shows that smokers are generally misinformed about the relative harmfulness of nicotine, and smokeless forms of nicotine delivery in relation to smoked tobacco. This study explores changing trends in the beliefs about the harmfulness and use of stop smoking medications and smokeless tobacco in adult smokers in four countries where public education and access to alternative forms of nicotine is varied (Canada, the US, the UK and Australia). METHODS: Data are from seven waves of the ITC-4 country study conducted between 2002 and 2009 with adult smokers from Canada, the US, the UK and Australia. For the purposes of this study, data were collected from 21,207 current smokers. Using generalised estimating equations to control for multiple response sets, multivariate models were tested to look for main effects of country, and trends across time, controlling for demographic variables. RESULTS: Knowledge remained low in all countries, although UK smokers tended to be better informed. There was a small but significant improvement across time in the UK, but mixed effects in the other three countries. At the final wave, between 37.5% (US) and 61.4% (UK) reported that NRT is a lot less harmful than cigarettes. In Canada and the US, where smokeless tobacco is marketed, only around one in six believed some smokeless tobacco products could be less harmful than cigarettes. CONCLUSIONS: Many smokers continue to be misinformed about the relative safety of nicotine and alternatives to smoked tobacco, especially in the US and Canada. Concerted efforts to educate UK smokers have probably improved their knowledge. Further research is required to assess whether misinformation deters smokers from appropriate use of alternative forms of nicotine

Impact of the New Malaysian Cigarette Pack Warnings on Smokers’ Awareness of Health Risks and Interest in Quitting Smoking

The objective of this research was to compare the response of adult smokers in Malaysia to newly proposed pictorial cigarette warnings against the current text-only warnings. The study population included 140 adult male smokers who were enrolled in a randomized trial to view either the new pictorial warnings (intervention) or the old text-only warnings (control). Participants completed pre-exposure and post-exposure questionnaires that assessed their awareness of the health risks of smoking, response to the package warnings, and interest in quitting smoking. Exposure to the pictorial warnings resulted in increased awareness of the risks of smoking, stronger behavioral response to the warnings and increased interest in quitting smoking. The new warnings in Malaysia will increase smokers’ knowledge of the adverse health effects of smoking and have a positive effect on interest in quitting

RF Design of Normal Conducting Deflecting Structures for the Advanced Photon Source

Use of normal conducting deflecting structures for production of short x-ray pulses is now under consideration at Argonne's Advanced Photon Source (APS). The structures have to produce up to 4 MV maximum deflection per pair of structures with a 1 kHz repetition rate. At the same time, the structures should not cause deterioration of beam properties in the APS ring. Following these requirements, we proposed 2815 MHz standing wave deflecting structures with heavy wakefield damping. In this paper we discuss design considerations and present our current design

Trends in Roll-Your-Own Smoking: Findings from the ITC Four-Country Survey (2002–2008)

Objective. To establish the trends in prevalence, and correlates, of roll-your-own (RYO) use in Canada, USA, UK and Australia, 2002–2008. Methods. Participants were 19,456 cigarette smokers interviewed during the longitudinal International Tobacco Control (ITC) Four-Country Survey in Canada, USA, UK, and Australia. Results. “Predominant” RYO use (i.e., >50% of cigarettes smoked) increased significantly in the UK and USA as a proportion of all cigarette use (both P < .001) and in all countries as a proportion of any RYO use (all P < .010). Younger, financially stressed smokers are disproportionately contributing to “some” use (i.e., ≤50% of cigarettes smoked). Relative cost was the major reason given for using RYO, and predominant RYO use is consistently and significantly associated with low income. Conclusions. RYO market trends reflect the price advantages accruing to RYO (a product of favourable taxation regimes in some jurisdictions reinforced by the enhanced control over the amount of tobacco used), especially following the impact of the Global Financial Crisis; the availability of competing low-cost alternatives to RYO; accessibility of duty-free RYO tobacco; and tobacco industry niche marketing strategies. If policy makers want to ensure that the RYO option does not inhibit the fight to end the tobacco epidemic, especially amongst the disadvantaged, they need to reduce the price advantage, target additional health messages at (young) RYO users, and challenge niche marketing of RYO by the industry

Regulatory mechanisms mediated by peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in skin cancer

Considerable progress has been made during the past twenty years towards elucidating the role of peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in skin cancer. In 1999, the original notion that PPARβ/δ was involved with epithelial cell function was postulated based on a correlation between PPARβ/δ expression and the induction of mRNAs encoding proteins that mediate terminal differentiation in keratinocytes. Subsequent studies definitively revealed that PPARβ/δ could induce terminal differentiation and inhibit proliferation of keratinocytes. Molecular mechanisms have since been discovered to explain how this nuclear receptor can be targeted for preventing and treating skin cancer. This includes the regulation of terminal differentiation, mitotic signaling, endoplasmic reticulum stress, and cellular senescence. Interestingly, the effects of activating PPARβ/δ can preferentially target keratinocytes with genetic mutations associated with skin cancer. This review provides the history and current understanding of how PPARβ/δ can be targeted for both non-melanoma skin cancer and melanoma, and postulates how future approaches that modulate PPARβ/δ signaling may be developed for the prevention and treatment of these diseases