A description and the measured performance of three coaxial beam-rotating antenna prototypes

Many high-power microwave (HPM) sources utilize an azimuthally symmetric output mode, like the TM/sub 01/ circular waveguide or the coaxial TEM modes. If radiated directly, these modes produce a doughnut-shaped radiation pattern, with a boresight . Mode-conversion techniques for transforming the azimuthally symmetric mode to one with a more desirable radiated pattern are possible, but mode conversion is typically undesirable, due to inefficiencies and due to increases in system size and weight. Antenna designs have been explored that will radiate the azimuthally symmetric mode directly, but those considered to date tend to exhibit low gain, and do not radiate a boresight peak (along the longitudinal axis of the source). This article describes the measured performance of three prototype antennas, all of the coaxial beam-rotating antenna (COBRA) class. These accept directly an azimuthally symmetric mode, and radiate a high-gain, circularly polarized beam with a boresight peak. The antennas achieve this capability by varying the electrical length of a path from a focal point to the aperture plane as a function of the azimuthal angle of the aperture. A brief overview of the general theory of COBRA operation is first presented. Next, measured data, characteristic of the input impedance and far-field patterns of three COBRA prototypes, are given. The architectures of COBRA prototypes reviewed in this article include those utilizing (1) a single, stepped paraboloidal reflector; (2) a dual reflector; and (3) a dual reflector with a coaxial feed.     

Live cell calcium imaging at the single ion hit facility of GSI

To study the fast intracellular calcium response after ion irradiation in living mammalian cells, a live cell calcium imaging set-up was constructed at the targeted cell irradiation facility at GSI. This work introduces the live cell calcium imaging system, shows its performance, an example of the ratio-metric calcium measurement and its application to on-line study calcium response to targeted ion irradiation in human cells.     

Cloning,Expression and Purification of Cindoxin,an Unusual Fmn‐Containing Cytochrome P450 Redox Partner

Cytochromes P450 (P450s) belong to a superfamily of haemoproteins that catalyse a remarkable variety of oxidative transformations. P450 catalysis generally requires that cognate redox proteins transfer electrons, derived ultimately from NAD(P)H, to the P450 for oxygen activation. P450_cin (CYP176A1) is a bacterial P450 that is postulated to allow Citrobacter braakii to live on cineole as its sole carbon source by initiating cineole biodegradation. Here we report the cloning, expression, purification and characterisation of one of its postulated redox partners, cindoxin (Cdx), which has strong similarity to the FMN domain of cytochrome P450 reductase. Cindoxin reductase (CdR), which displays strong similarity to NADPH‐dependent ferredoxin reductases, was unable to be expressed in a functional form. Mass spectrometric and HPLC analyses confirmed that the flavin cofactor of cindoxin was FMN. Redox potentiometric titrations were performed with cindoxin within the range 6<pH<8; this enabled the quinone/semiquinone (E₁) and semiquinone/hydroquinone (E₂) redox potentials to be determined. Our results show that cindoxin might be somewhat different to other flavodoxins that interact with P450s, in which generally only one couple is important. Both redox states of cindoxin could be catalytically relevant. A catalytically active system was reconstituted in vitro with E. coli flavodoxin reductase (Fpr) acting as the terminal redox partner in the absence of CdR. Our results show that Cdx and Fpr support regio‐ and stereoselective P450_cin‐catalysed cineole oxidation to (1R)‐6β‐hydroxycineole with turnover rates up to 1500 min^?1. This system is tightly coupled with 80 % of NADPH reducing equivalents funnelled into substrate oxidation.     

"Treating traumatized OEF/OIF veterans: How does trauma treament affect the clinician?": Correction to Voss Horrell et al. (2011).

Reports an error in "Treating traumatized OEF/OIF veterans: How does trauma treatment affect the clinician" by Sarah C. Voss Horrell, Dana R. Holohan, Lea M. Didion and G. Todd Vance (Professional Psychology: Research and Practice, 2011[Feb], Vol 42[1], 79-86). The word “While” was erroneously inserted in the first sentence of the “Clinician Factors” section. The corrected sentence is provided in the erratum. (The following abstract of the original article appeared in record 2011-04544-011.) The authors of this article describe the rewards and challenges for clinicians treating veterans who have served in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). Issues of vicarious trauma, secondary traumatic stress, compassion fatigue, and burnout are defined and reviewed, as are compassion satisfaction and posttraumatic growth. Patient, clinician, and organizational characteristics that are likely to affect clinicians working with this clinical population are discussed. Patient factors that may increase strain on clinicians are discussed such as age, likelihood of redeployment, comorbid conditions, attendance issues, and elevated risk for suicide and aggression. Clinician factors, such as theoretical orientation, training, supervision, military affiliation, personal trauma history, spirituality, social support, and self-care, are also discussed as possible risk and protective factors for vicarious trauma and burnout. Organizational influences, such as caseload size and diversity, clinician control and autonomy, use of evidence-based practices, availability of resources, rural isolation, and the philosophy of the clinic, are further discussed. Recommendations for ameliorating risks are discussed relative to each area and include allowing clinicians to plan their own appointments so as to balance their caseload of OEF/OIF veterans, attending to self-care practices, and having a supportive team with thorough training in evidence-based practices. Future empirical research is needed on risk and resiliency factors for clinicians working with traumatized OEF/OIF veterans given that this population is likely to grow. (PsycINFO Database Record (c) 2011 APA, all rights reserved)