Intracellular pH regulation in isolated trout gill mitochondrion-rich (MR) cell subtypes: Evidence for Na\u3csup\u3e+\u3c/sup\u3e/H\u3csup\u3e+\u3c/sup\u3e activity

We have studied intracellular pH (pHi) recovery in isolated trout gill mitochondrion-rich (MR) cells following acidification by the NH4Cl pre-pulse technique. Within a mixed MR cell population, one cell type displayed Na+-independent pHi recovery while the other cell type lacked a Na+-independent pHi recovery. Cells displaying Na+ independent recovery exhibited a significantly higher buffering capacity compared to cells lacking Na+-independent pHi recovery. Cells displaying Na+ independent recovery were identified as PNA+ (peanut lectin agluttinin binding) MR cells while those unable to recover were identified as PNA- (non-peanut lectin agluttinin binding) MR cells. Therefore, recovery from acidification in the absence of Na+ provides a direct functional marker for PNA+ and PNA- MR cells. Re-addition of Na+ to acidified cells resulted in a transient pHi recovery in both cell types. This event was abolished by amiloride (500 μM) but it was insensitive to phenamil (50 μM). The phorbol ester PMA (1 μM) potentiated the Na+ induced pHi recovery suggesting that activation by PKC is required for continuous Na+/H+ exchanger activity in trout gill MR cells. This study is the first functional description of pHi recovery in lectin-identified trout gill MR cells and provides insight into a putative cellular signaling mechanism that may control pHi regulation in the gill epithelium. © 2009 Elsevier Inc. All rights reserved

NGC7538 IRS1 - an ionized jet powered by accretion

Analysis of high spatial resolution VLA images shows that the free-free emission from NGC7538 IRS1 is dominated by a collimated ionized wind. We have re-analyzed high angular resolution VLA archive data from 6 cm to 7 mm, and measured separately the flux density from the compact bipolar core and the extended (1.5" - 3") lobes. We find that the flux density of the core is proportional to the frequency to the power of alpha, with alpha being about 0.7. The frequency dependence of the total flux density is slightly steeper with alpha = 0.8. A massive optically thick hypercompact core with a steep density gradient can explain this frequency dependence, but it cannot explain the extremely broad recombination line velocities observed in this source. Neither can it explain why the core is bipolar rather than spherical, nor the observed decrease of 4% in the flux density in less than 10 years. An ionized wind modulated by accretion is expected to vary, because the accretion flow from the surrounding cloud will vary over time. BIMA and CARMA continuum observations at 3 mm show that the free-free emission still dominates at 3 mm. HCO+ J = 1 - 0 observations combined with FCRAO single dish data show a clear inverse P Cygni profile towards IRS1. These observations confirm that IRS1 is heavily accreting with an accretion rate of about 2 times 10(-4) solar masses per year.Comment: Accepted for Astrophysical Journal Letter

The importance of data issues when comparing cystic fibrosis registry outcomes between countries : are annual review FEV1 in the UK only collected when subjects are well?

Rationale, aims and objective Cross‐country comparisons of cystic fibrosis (CF) outcomes can potentially identify variation in care but are dependent on data quality. An important assumption is that the UK annual review FEV1 is only collected during periods of clinical stability. If this assumption does not hold, results of FEV1 comparisons may be biased in favour of registries with encounter‐based FEV1. We aimed to test the assumption that CF annual reviews in the UK are only performed during periods of clinical stability. Method Prospective encounter‐based data collected in Sheffield (n = 174) was used to establish whether annual review FEV1 were always collected during periods of clinical stability and to determine the group‐level discrepancy between annual review vs best FEV1. We then went on to quantify the group‐level discrepancy between annual review and best annual FEV1 readings within the UK registry (n = 2995) to determine if the differences observed in Sheffield also apply to the wider UK data. Results Sheffield results showed a group‐level discrepancy between best and annual review FEV1 of −2.5% (95% CI −3.95% to −1.2%) for annual reviews performed during periods of clinical stability (n = 50). The group‐level discrepancy is larger at −8.0% (95% CI −11.2% to −4.9%) among annual reviews performed during periods of clinical instability (n = 13). Therefore, the magnitude of this group‐level discrepancy is a surrogate for the proportion of clinically stable annual reviews—smaller discrepancy indicates a higher proportion of clinically stable annual reviews and vice versa. The overall group‐level discrepancy in the UK registry (−5.6%, 95% CI −5.9 to −5.4%) was similar to Sheffield (−6.1%, 95% CI −7.1 to −5.1%). Around 20% of the clinician reviewed, annual reviews in Sheffield were performed during periods of clinically instability. Conclusions Annual review FEV1 underestimates lung health of adults with CF in the UK and may bias cross‐country comparisons

The Formaldehyde Masers in Sgr B2: Very Long Baseline Array and Very Large Array Observations

Observations of two of the formaldehyde (H2CO) masers (A and D) in Sgr B2 using the VLBA+Y27 (resolution ~0.01") and the VLA (resolution ~9") are presented. The VLBA observations show compact sources (<10 milliarcseconds, <80 AU) with brightness temperatures >10^8 K. The maser sources are partially resolved in the VLBA observations. The flux densities in the VLBA observations are about 1/2 those of the VLA; and, the linewidths are about 2/3 of the VLA values. The applicability of a core-halo model for the emission distribution is demonstrated. Comparison with earlier H2CO absorption observations and with ammonia (NH3) observations suggests that H2CO masers form in shocked gas. Comparison of the integrated flux densities in current VLA observations with those in previous observations indicates that (1) most of the masers have varied in the past 20 years, and (2) intensity variations are typically less than a factor of two compared to the 20-year mean. No significant linear or circular polarization is detected with either instrument.Comment: 20 pages, 3 figures, 5 tables, accepted to Ap

Large scale evaluation of photovoltaic technologies in different climates

Photovoltaic systems are typically optimised for performance or cost. In order to evaluate the wider parameter space and extensive measurement campaign has been designed that will provide guidance on future system designs. Four near-identical, grid-connected 200kW PV systems are being installed onto IKEA home furnishings stores in four countries with different climatic classification. The systems are integrated with comprehensive weather and power monitoring systems. This paper reports on the design, installation and scientific objectives of the project

Inter-continental optimisation of photovoltaic technologies in large arrays

Photovoltaic systems are typically optimised for performance or cost. In order to evaluate the wider parameter space an extensive measurement campaign has been designed that will provide guidance on future system designs. Four near-identical, grid-connected 200kWP PV systems are being installed onto IKEA home furnishings stores in four countries with different climatic classifications. The systems are integrated with comprehensive weather and power monitoring systems. This paper introduces the project and presents initial results

Gas phase thermometry of hot turbulent jets using laser induced phosphorescence

This article is made available through the Brunel Open Access Publishing Fund. Copyright @ 2013 OSAThe temperature distributions of heated turbulent jets of air were determined using two dimensional (planar) laser induced phosphorescence. The jets were heated to specific temperature increments, ranging from 300 – 850 K and several Reynolds numbers were investigated at each temperature. The spectral ratio technique was used in conjunction with thermographic phosphors BAM and YAG:Dy, individually. Single shot and time averaged results are presented as two dimensional stacked images of turbulent jets. YAG:Dy did not produce a high enough signal for single shot measurements. The results allowed for a direct comparison between BAM and YAG:Dy, revealing that BAM is more suitable for relatively lower temperature, fast and turbulent regimes and that YAG:Dy is more suited to relatively higher temperature, steady flow situations

Large scale evaluation of photovoltaic technologies in different climates

Most solar photovoltaic (PV) optimisation work to date has tended to take a reductionist approach, focusing on how individual parameters affect energy performance of systems. The impact of design choices on financial payback have been researched separately, thereby overlooking potentially significant interactions. This paper presents a project taking a more holistic approach to the problem of system optimisation. It is unique in taking a systems engineering approach to solar PV research, and recognises the needs of designers and specifiers in analysing the effect of design choices on financial payback. Four near-identical, grid-connected 200kW PV systems are being installed onto large commercial rooftops in urban areas, with comprehensive monitoring systems, therefore high quality data will be used to validate any models used. This paper reports on the initial set-up and the design of the scientific analysis

Large scale PV system monitoring - modules technology intercomparison

This paper presents an initial analysis of a large scale PV system monitoring campaign. Ongoing project aims to be a detailed inter-comparison of different modules technologies installed in a different types of climates, identifying optimal configurations in different climatic zones. Detailed description of created plants and developed monitoring facilities was shown. Appropriate performance indicators are discussed and applied to the measurements of two sites. The resulting performance analysis of different modules technologies, is presented and discussed. Differences between crystalline and thin film technologies were marked, with thin film technologies not performing as well as expected. This is most likely due to installation issues and will be rectified in the near future.. Further investigations will be undertaken and reported in close future