Application of electron multiplying CCD technology in space instrumentation

Electron multiplying CCD (EMCCD) technology has found important initial applications in low light surveillance and photon starved scientific instrumentation. This paper discusses the attributes of the EMCCD which make it useful for certain space instruments, particularly those which are photon starved, and explores likely risks from the radiation expected in such instruments

Low noise charge injection in the CCD22

The inclusion of a charge injection structure on a charge coupled device (CCD) allows for the mitigation of charge transfer loss which can be caused by radiation induced charge trapping defects. Any traps present in the pixels of the CCD are filled by the injected charge as it is swept through the device and consequently, the charge transfer efficiency is improved in subsequently acquired images. To date, a number of different types of CCD have been manufactured featuring a variety of charge injection techniques. The e2v Technologies CCD22, used in the EPIC MOS focal plane instruments of XMM-Newton, is one such device and is the subject of this paper. A detailed understanding of charge injection operation and the use of charge injection to mitigate charge transfer losses resulting from radiation damage to CCDs will benefit a number of space projects planned for the future, including the ESA GAIA and X-ray Evolving Universe Spectrometry (XEUS) missions.The charge injection structure and mode of operation of the CCD22 are presented, followed by a detailed analysis of the uniformity and repeatability of the charge injection amplitude across the columns of the device. The effects of proton irradiation on the charge injection characteristics are also presented, in particular the effect of radiation induced bright pixels on the injected charge level

Synaptic tagging and capture : differential role of distinct calcium/calmodulin kinases in protein synthesis-dependent long-term potentiation

Weakly tetanized synapses in area CA1 of the hippocampus that ordinarily display long-term potentiation lasting ~3 h (called early-LTP) will maintain a longer-lasting change in efficacy (late-LTP) if the weak tetanization occurs shortly before or after strong tetanization of an independent, but convergent, set of synapses in CA1. The synaptic tagging and capture hypothesis explains this heterosynaptic influence on persistence in terms of a distinction between local mechanisms of synaptic tagging and cell-wide mechanisms responsible for the synthesis, distribution, and capture of plasticity-related proteins (PRPs). We now present evidence that distinct CaM kinase (CaMK) pathways serve a dissociable role in these mechanisms. Using a hippocampal brain-slice preparation that permits stable long-term recordings in vitro for >10 h and using hippocampal cultures to validate the differential drug effects on distinct CaMK pathways, we show that tag setting is blocked by the CaMK inhibitor KN-93 (2-[N-(2-hydroxyethyl)]-N-(4-methoxybenzenesulfonyl)amino-N-(4-chlorocinnamyl)-N-methylbenzylamine) that, at low concentration, is more selective for CaMKII. In contrast, the CaMK kinase inhibitor STO-609 [7H-benzimidazo(2,1-a)benz(de)isoquinoline-7-one-3-carboxylic acid] specifically limits the synthesis and/or availability of PRPs. Analytically powerful three-pathway protocols using sequential strong and weak tetanization in varying orders and test stimulation over long periods of time after LTP induction enable a pharmacological dissociation of these distinct roles of the CaMK pathways in late-LTP and so provide a novel framework for the molecular mechanisms by which synaptic potentiation, and possibly memories, become stabilized

Characterization of a Novel Clade of Transporters in Phytophthora

The oomycete Phytophthora parasitica has a worldwide distribution and is an economically important pathogen of more than 100 species4. RNA-seq analysis showed that one gene, PPTG_16698 has the 5th highest level of expression of all transport proteins in the zoospore stage, and is highly conserved throughout Phytophthora species. This project attempts to characterize the important biological role that PPTG_16698 plays in P. parasitica and other oomycetes. Three strategies have been implemented to accomplish this goal: growth analysis by heterologous expression in yeast, metabolite analysis in yeast, and construction of a GFP fusion protein to enable localization of the gene in oomycete hyphae by confocal microscopy. Confocal microscopy is expected to confirm the vacuolar localization of this gene. If this gene is localized to a vacuolar membrane, then heterologous expression in yeast should result in differential accumulation of metabolites mobilized by this transporter. In preliminary growth assays, expression of this gene did not inhibit the growth of yeast. Therefore, expression of the gene does not result in sequestering of a growth-limiting metabolite. To determine whether expression of the transporter results in the accumulation of polyamines, which are organic compounds necessary for growth in eukaryotes, polyamine levels will be measured by dansylation of amines and separation by HPLC. Other metabolites will be assayed by liquid chromatography mass spectroscopy analysis

The Effect of Sleep Quality and Being Physically Active on Developing Mental Toughness

Mental toughness (MT) has been increasingly associated with successful performance in several stressful and competitive environments (e.g. the military, business, academics, medicine, sports). Being physically active (PA) may compromise sleep quality (SQ). Research has reported conflicting associations regarding PA and MT. Regarding SQ and MT, a bidirectional association has been reported. However, research has not yet focused on the combined effects of PA and SQ on MT. PURPOSE: To characterize the association and the effects of PA and SQ on MT. The authors hypothesized that: (a) PA and SQ are negatively associated; (b) PA and MT are positively associated; (c) SQ and MT are negatively associated; and (d) the interaction effect of PA and SQ on MT will be buffering. METHODS: Sixty-two participants (age 25.4 6.0 SD) completed inventories related to SQ (Pittsburgh Sleep Quality Index) and MT (Mental Toughness Index). PA data were collected according to American College of Sports Medicine guidelines. Main and interaction effects of the responses were analyzed using factorial ANOVA. Significance was set at p \u3c 0.05. All analyses were performed using SPSS. RESULTS: PA was positively correlated with SQ (r = .009, p =.473) and with MT (r = .246, p = .027). SQ was negatively correlated with MT (r = -.470, p = .000). PA (F1,58 = 10.939, p = .002, η2 = .159) and QS (F1,58 = 23.051, p = .000, η2 = .284) had a main effect on MT. The interaction of PA and QS had a buffering moderating effect on MT (F1,58 = 12.394, p = .001, η2 = .176). CONCLUSION: Evidence was found for all but the first hypothesis. PA-participants tending to be mentally tougher than the non-PA ones. Poor sleepers, on average, were mentally tougher than the good sleepers. The buffering effect indicates that the non-PA individuals with poor quality of sleep are the mentally toughest ones, followed by PA individuals with poor quality of sleep. Non-PA individuals with good quality of sleep present the lowest MT levels. In regards to developing mental toughness the authors suggest that: a) PA should be prescribed to good quality of sleepers and b) in poor quality sleepers focus should be placed on sleep before PA. Such findings may be useful to exercise and health-related practitioners when prescribing PA in a wide variety of individuals that report sleep quality issues in relation to MT capacities

Handgrip Strength and VO2max Trends in Police Cadets: A Case Study

Among other components of physical fitness, performance on tactical tasks depends on cardiorespiratory endurance (CE) and muscular strength (MS). Police academies’ curriculum aim to increase cadets’ CE and MS, with males outscoring females in both tests. Curricula should assist cadets to adopt and adhere to a physically-active lifestyle while in the academy and upon graduation, for both health-related benefits and success in their tactical tasks. PURPOSE: To explore both CE-MS and sex trends between a four-year curriculum. METHODS: Retrospective data of 98 males and 79 females analyzed. Besides the senior year, cadets receive physical education classes. This serves as the foundation for adopting and adhering to physically-active lifestyle during their senior and postgraduation years by applying different training methods on their own. As part of their yearly evaluation, cadets completed a 12-min Cooper and a handgrip strength test. Estimated VO2max and absolute bilateral handgrip strength (HS) used as dependent variables. A multivariate analysis of variance (MANOVA) 4X2 for academic years and sex performed using SPSSÓ. RESULTS: Using Pillai’s trace, there was a significant effect of academic years, V=.09, F6,338=2.6, p=.02, η2 =.04 and sex, V=.80, F2,168=344.4,

The two homologous chaperonin 60 proteins of Mycobacterium tuberculosis have distinct effects on monocyte differentiation into osteoclasts.

Mycobacterium tuberculosis produces two homologous chaperonin (Cpn)60 proteins, Cpn60.1 and Cpn60.2 (Hsp65). Both proteins stimulate human and murine monocyte cytokine synthesis but, unlike Cpn60 proteins from other microbial species, fail to stimulate the breakdown of cultured murine bone. Here, we have examined the mechanism of action of these proteins on bone remodelling and osteoclastogenesis, induced in vitro in murine calvarial explants and the murine monocyte cell line RAW264.7. Additionally, we have determined their effect on bone remodelling in vivo in an animal model of arthritis. Recombinant Cpn60.1 but not Cpn60.2 inhibited bone breakdown both in vitro, in murine calvaria and in vivo, in experimental arthritis. Analysis of the mechanism of action of Cpn60.1 suggests that this protein works by directly blocking the synthesis of the key osteoclast transcription factor, nuclear factor of activated T cells c1. The detection of circulating immunoreactive intact Cpn60.1 in a small number of patients with tuberculosis but not in healthy controls further suggests that the skeleton may be affected in patients with tuberculosis. Taken together, these findings reveal that M. tuberculosis Cpn60.1 is a potent and novel inhibitor of osteoclastogenesis both in vitro and in vivo and a potential cure for bone-resorptive diseases like osteoporosis