Interest in therapeutic applications of carbon monoxide release to physiological targets has led us to explore a photochemical strategy for such CO delivery. Here, we describe the photoactivated ...carbon monoxide releasing moiety (photoCORM), W(CO)(5)(TPPTS)(3-) (1), an air-stable, water-soluble tungsten(0) carbonyl complex of the trianionic ligand tris(sulphonatophenyl)phosphine. Near-UV photolysis of 1 in an aqueous buffer solution leads to the high quantum yield release of a single CO, the formation of which has been verified by three analytical methodologies. Furthermore, in aerated media, additional CO is slowly released from the W(CO)(4)(H(2)O)(TPPTS)(3-) photoproduct owing to autoxidation of the tungsten center. Thus, 1 serves as a carbon monoxide releasing moiety both in the primary photochemical reaction and in the secondary reactions of the initially formed photoproduct. The three methodologies for quantifying CO release under these physiologically relevant conditions are also described.
LepR3, found in the Brassica napus cv ‘Surpass 400’, provides race-specific resistance to the fungal pathogen Leptosphaeria maculans, which was overcome after great devastation in Australia in 2004. ...We investigated the LepR3 locus to identify the genetic basis of this resistance interaction.
We employed a map-based cloning strategy, exploiting collinearity with the Arabidopsis thaliana and Brassica rapa genomes to enrich the map and locate a candidate gene. We also investigated the interaction of LepR3 with the L. maculans avirulence gene AvrLm1 using transgenics.
LepR3 was found to encode a receptor-like protein (RLP). We also demonstrated that aviru-lence towards LepR3 is conferred by AvrLm1, which is responsible for both the Rlm1 and LepR3-dependent resistance responses in B. napus.
LepR3 is the first functional B. napus disease resistance gene to be cloned. AvrLm1's interaction with two independent resistance loci, Rlm1 and LepR3, highlights the need to consider redundant phenotypes in ‘gene-for-gene’ interactions and offers an explanation as to why LepR3 was overcome so rapidly in parts of Australia.
A conceptual design is presented of a novel energy-recovering linac (ERL) facility for the development and application of the energy recovery technique to linear electron accelerators in the ...multi-turn, large current and large energy regime. The main characteristics of the powerful energy recovery linac experiment facility (PERLE) are derived from the design of the Large Hadron electron Collider, an electron beam upgrade under study for the LHC, for which it would be the key demonstrator. PERLE is thus projected as a facility to investigate efficient, high current (HC) (>10 mA) ERL operation with three re-circulation passages through newly designed SCRF cavities, at 801.58 MHz frequency, and following deceleration over another three re-circulations. In its fully equipped configuration, PERLE provides an electron beam of approximately 1 GeV energy. A physics programme possibly associated with PERLE is sketched, consisting of high precision elastic electron-proton scattering experiments, as well as photo-nuclear reactions of unprecedented intensities with up to 30 MeV photon beam energy as may be obtained using Fabry-Perot cavities. The facility has further applications as a general technology test bed that can investigate and validate novel superconducting magnets (beam induced quench tests) and superconducting RF structures (structure tests with HC beams, beam loading and transients). Besides a chapter on operation aspects, the report contains detailed considerations on the choices for the SCRF structure, optics and lattice design, solutions for arc magnets, source and injector and on further essential components. A suitable configuration derived from the here presented design concept may next be moved forward to a technical design and possibly be built by an international collaboration which is being established.
► We describe desired properties for photochemical CO delivery to biological targets. ► We also describe analytical challenges encountered in developing photoCORMs. ► We outline previous ...investigations of photoCORMs published by us and others. ► We present a new class of photoCORMs where CO is labilized by visible light.
The potential therapeutic effects of carbon monoxide in several disease states, and new methodologies for CO delivery to specific targets is a topic of growing interest in mammalian physiology. Here we provide an overview of recent efforts in this laboratory regarding several types of carbonyl complexes of the group 6 metal and of those in other laboratories that are focused on developing photochemical techniques for such CO delivery. Photo-activated carbon monoxide releasing moieties (photoCORMs) based on manganese, iron and group 6 metals are described.
Phoma stem canker is an internationally important disease of oilseed rape (Brassica napus, canola, rapeseed), causing serious losses in Europe, Australia and North America. UK losses of euros 56M per ...season are estimated using national disease survey data and a yield loss formula. Phoma stem canker pathogen populations comprise two main species, Leptosphaeria maculans, associated with damaging stem base cankers, and Leptosphaeria biglobosa, often associated with less damaging upper stem lesions. Both major gene and quantitative trait loci mediated resistance to L. maculans have been identified in B. napus, but little is known about resistance to L. biglobosa. Leptosphaeria maculans, which has spread into areas in North America and eastern Europe where only L. biglobosa was previously identified, now poses a threat to large areas of oilseed rape production in Asia. Epidemics are initiated by air-borne ascospores; major gene resistance to initial infection by L. maculans operates in the leaf lamina of B. napus. It is not clear whether the quantitative trait loci involved in the resistance to the pathogen that can be assessed only at the end of the season operate in the leaf petioles or stems. In countries where serious phoma stem canker epidemics occur, a minimum standard for resistance to L. maculans is included in national systems for registration of cultivars. This review provides a background to a series of papers on improving strategies for managing B. napus resistance to L. maculans, which is a model system for studying genetic interactions between hemi-biotrophic pathogens and their hosts.
Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility are collaborating on the design and construction of the next Electron Ion Collider (EIC) to be built at BNL. ...The EIC is a unique high-energy, high-luminosity, polarized electron-proton/ion collider. The EIC accelerator complex needs about 10 new rf and SRF systems with frequencies spanning 24 MHz to 1773 MHz, requiring more than 60 new high-power fundamental power couplers (FPCs). These couplers will operate in either pulsed mode or continuous wave mode with peak traveling wave power ranging from 10 s to 380 kW. Here we present our design for a 1-MW broadband rf window suitable for EIC rf and SRF systems with operating frequencies up to 591 MHz. This design takes advantage of the numerous synergies between the various rf and SRF systems to make it broadly applicable. The rf window design criteria are based on the requirement for the 591-MHz electron storage ring (ESR) SRF cavities, as it will operate at both the highest traveling wave power and the highest peak power over the EICrf/SRFcomplex. The results presented will detail the FPC power requirement, rf window choices, design criteria, and multiphysics performance in the most critical application, the ESR SRF cavity, and how the rf window design applies to other EICrf/SRFsystems.
Free electron lasers: Present status and future challenges Barletta, W.A.; Bisognano, J.; Corlett, J.N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2010, Letnik:
618, Številka:
1
Journal Article
Recenzirano
With the scientific successes of the soft X-ray FLASH facility in Germany and the recent spectacular commissioning of the Linac Coherent Light Source at SLAC, free electron lasers are poised to take ...center stage as the premier source of tunable, intense, coherent photons of either ultra-short time resolution or ultra-fine spectral resolution, from the far infrared to the hard X-ray regime. This paper examines the state of the art in FEL performance and the underlying enabling technologies. It evaluates the state of readiness of the three basic machine architectures—SASE FELs, seeded FELs, and FEL oscillators—for the major X-ray science user facilities on the 5–10 years time scale and examines the challenges that lie ahead for FELs to achieve their full potential throughout the entire spectral range. In soft and hard X-rays, high longitudinal coherence, in addition to full transverse coherence, will be the key performance upgrade; ideas using laser-based or self-seeding or oscillators can be expected to be qualitatively superior to today's SASE sources. Short pulses, from femtoseconds to attoseconds, can be realistically envisioned. With high repetition rate electron sources coupled to superconducting radiofrequency linear accelerators, unprecedented average beam brightness will be possible and many users would be served simultaneously by a single accelerator complex.
Beam test of a harmonic kicker cavity Bruker, M W; Grames, J; Guo, J ...
Journal of physics. Conference series,
01/2024, Letnik:
2681, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
A harmonically resonant kicker cavity designed for beam exchange in a circulator cooler was built and successfully tested at the Upgraded Injector Test Facility (UITF) at Jefferson Lab. This ...type of cavity is being considered for the injection scheme of the Rapid Cycling Synchrotron at the Electron-Ion Collider, where the spacing of neighboring bunches demands very short kicks. Operating with five transversely deflecting modes simultaneously that resonate at 86.6 MHz and consecutive odd harmonics thereof, the prototype cavity selectively deflects 1 of 11 electron bunches while leaving the others unperturbed. An RF driver was developed to synthesize phase- and amplitude-controlled harmonic signals and combine them to drive the cavity while also separating the modes from a field-probe antenna for RF feedback and dynamic tuning. Beam deflection was measured by sweeping the cavity phase; the deflection waveform agrees with expectations, having sub-nanosecond rise and fall times. No emittance increase is observed. Harmonically resonant cavities like the one described provide a new capability for injection and extraction at circulators and rings.
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