Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling

Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH₄ mixing ratios measured by the different platforms. To address uncertainty about where CH₄ emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH₄ emission areas. We found small differences between the CH₄ mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH₄ fluxes. The CH₄ flux during the campaign was small, with an upper limit of 2.5 nmol m^-2 s^-1 in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH₄ fluxes from the Svalbard continental platform below 0.2 Tg yr^-1. All estimates are in the lower range of values previously reported.

Measurements of δ13C in CH4 and using particle dispersion modeling to characterize sources of Arctic methane within an air mass

A stratified air mass enriched in methane (CH4) was sampled at ~600 m to ~2000 m altitude, between the north coast of Norway and Svalbard as part of the Methane in the Arctic: Measurements and Modelling campaign on board the UK's BAe-146-301 Atmospheric Research Aircraft. The approach used here, which combines interpretation of multiple tracers with transport modeling, enables better understanding of the emission sources that contribute to the background mixing ratios of CH4 in the Arctic. Importantly, it allows constraints to be placed on the location and isotopic bulk signature of the emission source(s). Measurements of δ13C in CH4 in whole air samples taken while traversing the air mass identified that the source(s) had a strongly depleted bulk δ13C CH4 isotopic signature of -70 (±2.1)‰. Combined Numerical Atmospheric-dispersion Modeling Environment and inventory analysis indicates that the air mass was recently in the planetary boundary layer over northwest Russia and the Barents Sea, with the likely dominant source of methane being from wetlands in that region.

MEGAPOLI: concept of multi-scale modelling of megacity impact on air quality and climate

Abstract. The EU FP7 Project MEGAPOLI: "Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation" (http://megapoli.info) brings together leading European research groups, state-of-the-art scientific tools and key players from non-European countries to investigate the interactions among megacities, air quality and climate. MEGAPOLI bridges the spatial and temporal scales that connect local emissions, air quality and weather with global atmospheric chemistry and climate. The suggested concept of multi-scale integrated modelling of megacity impact on air quality and climate and vice versa is discussed in the paper. It requires considering different spatial and temporal dimensions: time scales from seconds and hours (to understand the interaction mechanisms) up to years and decades (to consider the climate effects); spatial resolutions: with model down- and up-scaling from street- to global-scale; and two-way interactions between meteorological and chemical processes.

The global atmospheric environment for the next generation

Air quality, ecosystem exposure to nitrogen deposition, and climate change are intimately coupled problems: we assess changes in the global atmospheric environment between 2000 and 2030 using 26 state-of-the-art global atmospheric chemistry models and three different emissions scenarios. The first (CLE) scenario reflects implementation of current air quality legislation around the world, while the second (MFR) represents a more optimistic case in which all currently feasible technologies are applied to achieve maximum emission reductions. We contrast these scenarios with the more pessimistic IPCC SRES A2 scenario. Ensemble simulations for the year 2000 are consistent among models and show a reasonable agreement with surface ozone, wet deposition, and NO2 satellite observations. Large parts of the world are currently exposed to high ozone concentrations and high deposition of nitrogen to ecosystems. By 2030, global surface ozone is calculated to increase globally by 1.5 +/- 1.2 ppb (CLE) and 4.3 +/- 2.2 ppb (A2), using the ensemble mean model results and associated +/-1 sigma standard deviations. Only the progressive MFR scenario will reduce ozone, by -2.3 +/- 1.1 ppb. Climate change is expected to modify surface ozone by -0.8 +/- 0.6 ppb, with larger decreases over sea than over land. Radiative forcing by ozone increases by 63 +/- 15 and 155 +/- 37 mW m(-2) for CLE and A2, respectively, and decreases by -45 +/- 15 mW m(-2) for MFR. We compute that at present 10.1% of the global natural terrestrial ecosystems are exposed to nitrogen deposition above a critical load of 1 g N m(-2) yr(-1). These percentages increase by 2030 to 15.8% (CLE), 10.5% (MFR), and 25% (A2). This study shows the importance of enforcing current worldwide air quality legislation and the major benefits of going further. Nonattainment of these air quality policy objectives, such as expressed by the SRES-A2 scenario, would further degrade the global atmospheric environment.

Characteristics and scaling of tungsten-wire-array z -pinch implosion dynamics at 20 MA

We present observations for 20-MA wire-array z pinches of an extended wire ablation period of 57%+/-3% of the stagnation time of the array and non-thin-shell implosion trajectories. These experiments were performed with 20-mm-diam wire arrays used for the double- z -pinch inertial confinement fusion experiments [M. E. Cuneo, Phys. Rev. Lett. 88, 215004 (2002)] on the Z accelerator [R. B. Spielman, Phys. Plasmas 5, 2105 (1998)]. This array has the smallest wire-wire gaps typically used at 20 MA (209 microm ). The extended ablation period for this array indicates that two-dimensional (r-z) thin-shell implosion models that implicitly assume wire ablation and wire-to-wire merger into a shell on a rapid time scale compared to wire acceleration are fundamentally incorrect or incomplete for high-wire-number, massive (>2 mg/cm) , single, tungsten wire arrays. In contrast to earlier work where the wire array accelerated from its initial position at approximately 80% of the stagnation time, our results show that very late acceleration is not a universal aspect of wire array implosions. We also varied the ablation period between 46%+/-2% and 71%+/-3% of the stagnation time, for the first time, by scaling the array diameter between 40 mm (at a wire-wire gap of 524 mum ) and 12 mm (at a wire-wire gap of 209 microm ), at a constant stagnation time of 100+/-6 ns . The deviation of the wire-array trajectory from that of a thin shell scales inversely with the ablation rate per unit mass: f(m) proportional[dm(ablate)/dt]/m(array). The convergence ratio of the effective position of the current at peak x-ray power is approximately 3.6+/-0.6:1 , much less than the > or = 10:1 typically inferred from x-ray pinhole camera measurements of the brightest emitting regions on axis, at peak x-ray power. The trailing mass at the array edge early in the implosion appears to produce wings on the pinch mass profile at stagnation that reduces the rate of compression of the pinch. The observation of precursor pinch formation, trailing mass, and trailing current indicates that all the mass and current do not assemble simultaneously on axis. Precursor and trailing implosions appear to impact the efficiency of the conversion of current (driver energy) to x rays. An instability with the character of an m = 0 sausage grows rapidly on axis at stagnation, during the rise time of pinch power. Just after peak power, a mild m = 1 kink instability of the pinch occurs which is correlated with the higher compression ratio of the pinch after peak power and the decrease of the power pulse. Understanding these three-dimensional, discrete-wire implosion characteristics is critical in order to efficiently scale wire arrays to higher currents and powers for fusion applications.

Assessing the effect of fatty acids on prostate carcinogenesis in humans: does self-reported dietary intake rank prostatic exposure correctly?

BACKGROUND

Dietary fatty acids may influence prostate carcinogenesis. Although the standard for assessing dietary effects in humans is the semiquantitative food-frequency questionnaire, the extent to which self-reported intake correctly ranks prostatic exposure is unknown.

OBJECTIVE

The objective was to examine the correlation between reported intakes of different fatty acids and their concentrations in prostate tissue.

DESIGN

This was a cross-sectional study of 52 men undergoing surgical resection of the prostate gland. Usual dietary intake of saturated, total unsaturated, oleic, and linoleic fatty acids over the previous year was estimated with use of a 122-item version of the Health Habits and History Questionnaire. Concentrations in prostate tissue were measured directly by use of gas chromatography in healthy tissue collected at the time of surgery and were expressed as a percentage of total fatty acids. Correlations with 4 measures of dietary intake [g/d, g/d adjusted for total daily energy intake, % of total fat (as g/d), and % of total energy] were evaluated by Spearman's rank-order correlation coefficients.

RESULTS

Linoleic acid concentrations in prostate tissue were significantly correlated with dietary intake expressed as g/d adjusted for total energy [r = 0.29 (95% CI: 0.03, 0.49), P = 0.04], % of total fat [r = 0.36 (0.14, 0.550), P = 0.008], and % of total energy [r = 0.28 (0.04, 0.49), P = 0.042], but not as g/d. Although mean concentrations of saturated, total unsaturated, and oleic fatty acids in prostate tissue resembled mean intakes for the group, prostatic concentrations did not correlate with individual intakes.

CONCLUSION

Self-reported intake of fatty acids is a satisfactory marker of prostatic exposure at the group level, but, with the exception of linoleic acid, does not correctly rank individuals with respect to intensity of exposure.

Prostatic levels of fatty acids and the histopathology of localized prostate cancer

PURPOSE

The consumption of various fatty acids has been associated with advanced stage and fatal prostate cancer. While numerous mechanisms have been postulated, to our knowledge there physiological data linking exposure and prognosis in humans are lacking. We examined prostatic levels of individual fatty acids in relation to the prevalence of histopathological characteristics associated with invasiveness and the risk of progression in 49 men undergoing radical prostatectomy for localized prostate cancer.

MATERIALS AND METHODS

Fatty acids were measured using capillary gas chromatography in fresh nonmalignant prostate tissue collected at surgery. Markers of invasiveness and increased risk of progression (Gleason sum 7 or greater, perineural invasion, anatomical or surgical margin involvement, extracapsular extension, seminal vesical involvement and stage T3 tumor) were evaluated separately. Each marker was dichotomized into a yes (case) and no (control) level with patients grouped accordingly. Mean concentrations were compared using the Wilcoxon rank sum test.

RESULTS

The percent of total prostatic polyunsaturated fat and polyunsaturated-to-saturated fat ratios were significantly lower in the presence of perineural invasion, seminal vesical involvement and stage T3 tumor (p = 0.02 to 0.049). alpha-Linolenic acid was significantly lower when tumor extended to an anatomical or surgical margin (p = 0.008). The omega-3 and omega-3-to-omega-6 fatty acid ratios were 1.5 to 3.3-fold lower in cases than in controls, reaching borderline significance in nearly all comparisons (p = 0.052 to 0.097). Saturated and monounsaturated fatty acids were not associated with the traits examined.

CONCLUSIONS

These data suggest that polyunsaturated fatty acids and perhaps essential fatty acids in particular help to regulate prostate carcinogenesis in humans.

The heart-brain connection

We have long known that patients with vascular disease in one system are at risk for vascular disease in other systems. Beyond this, we are recognizing the increased risk for cardiovascular patients to develop stroke not only as the result of arrhythmia, but also at the time of cardiovascular events or procedures. This presents clinical challenges to nurses with either neurological or cardiovascular expertise, requiring development of new awareness, clinical and critical thinking skills, and collaboration with their colleagues in other specialties. Three case studies illustrate patient presentations ranging from the subtle to the obvious. Pathophysiology of stroke is reviewed. Leading-edge management strategies and supporting literature highlight the benefits of prompt identification and management of the stroke patient. The Stroke Watch Action Team (SWAT) has proved to be an effective means of expediting patient identification and access to effective stroke treatment.

Prostatic levels of tocopherols, carotenoids, and retinol in relation to plasma levels and self-reported usual dietary intake

This study evaluated how prostatic levels of antioxidants relate to plasma levels and self-reported usual dietary intake. Definition of these relations may aid in interpreting studies of antioxidant exposure and prostate cancer risk. Between July 1996 and April 1997, plasma and prostatic tissue levels of tocopherols, carotenoids, and retinol were measured in 47 men undergoing radical prostatectomy or transurethral prostatectomy at Loyola University Medical Center, Maywood, Illinois, and an affiliate hospital. Dietary intake was measured by using a 122-item version of the Block Health Habits and History Questionnaire, and correlations were assessed with Pearson's coefficients. Prostatic levels of tocopherols and carotenoids (but not retinol) were significantly correlated with plasma levels (r= 0.31-0.56, p < 0.05-0.0001); the strongest correlations were associated with lycopene, beta-carotene, and gamma-tocopherol (0.56, 0.54, and 0.52, respectively; p < 0.0001). Relative concentrations of tocopherols and carotenoids in prostate tissue were proportionate to those in plasma. No correlation between prostatic levels and reported dietary intake was observed (r = -0.09 to 0.16, p < not significant). Adjustment for energy intake, body mass index, and serum lipids did not impact these relations. These results suggest that plasma levels of tocopherols and carotenoids better reflect prostatic exposure than self-reported usual dietary intake.

Calcium release and influx colocalize to the endoplasmic reticulum

Intracellular Ca2+ is released from intracellular stores in the endoplasmic reticulum (ER) in response to the second messenger inositol (1,4,5) trisphosphate (InsP3) [1,2]. Then, a poorly understood cellular mechanism, termed capacitative Ca2+ entry, is activated [3,4]; this permits Ca2+ to enter cells through Ca(2+)-selective Ca(2+)-release-activated ion channels [5,6] as well as through less selective store-operated channels [7]. The level of stored Ca2+ is sensed by Ca(2+)-permeant channels in the plasma membrane, but the identity of these channels, and the link between them and Ca2+ stores, remain unknown. It has been argued that either a diffusible second messenger (Ca2+ influx factor; CIF) [8] or a physical link [9,10] connects the ER Ca(2+)-release channel and store-operated channels; strong evidence for either mechanism is lacking, however [7,10]. Petersen and Berridge [11] showed that activation of the lysophosphatidic acid receptor in a restricted region of the oocyte membrane results in stimulation of Ca2+ influx only in that region, and concluded that a diffusible messenger was unlikely. To investigate the relationship between ER stores and Ca2+ influx, we used centrifugation to redistribute into specific layers the organelles inside intact Xenopus laevis oocytes, and used laser scanning confocal microscopy with the two-photon technique to 'uncage' InsP3 while recording intracellular Ca2+ concentration. Ca2+ release was localized to the stratified ER layer and Ca2+ entry to regions of the membrane directly adjacent to this layer. We conclude that Ca2+ depletion and entry colocalize to the ER and that the mechanism linking Ca2+ stores to Ca2+ entry is similarly locally constrained.

Conformational states of the nuclear pore complex induced by depletion of nuclear Ca2+ stores

The nuclear pore complex (NPC) is essential for the transit of molecules between the cytoplasm and nucleoplasm of a cell and until recently was thought to allow intermediate-sized molecules (relative molecular mass of approximately 10,000) to diffuse freely across the nuclear envelope. However, the depletion of calcium from the nuclear envelope of Xenopus laevis oocytes was shown to regulate the passage of intermediate-sized molecules. Two distinct conformational states of the NPC were observed by field emission scanning electron microscopy and atomic force microscopy. A central plug occluded the NPC channel after nuclear calcium stores had been depleted and free diffusion of intermediate-sized molecules had been blocked. Thus, the NPC conformation appears to gate molecular movement across the nuclear envelope.

Limited efficacy of preoperative computed tomographic scanning for the evaluation of lymph node metastasis in patients before radical prostatectomy

OBJECTIVES

To evaluate the efficacy of preoperative computed tomographic (CT) scanning in patients with presumed localized prostatectomy prior to radical retropubic prostatectomy.

METHODS

A retrospective study of 173 consecutive patients believed to be candidates for radical retropubic prostatectomy who underwent preoperative CT scanning regardless of preoperative prostate-specific antigen (PSA) value, clinical stage, or Gleason grade was undertaken. All patients underwent radical retropubic prostatectomy with bilateral pelvic lymph node dissection or aspiration needle biopsy of abnormal nodes on CT scanning.

RESULTS

One hundred sixty-five of 173 patients (95.4%) were believed to have normal CT scans preoperatively. Of these 165 patients, 156 (94.5%) were found to have negative lymph nodes confirmed histologically at the time of lymphadenectomy. Nine patients (5.5%) were found to have lymph node metastases confirmed histologically, despite a negative CT scan. Computed tomographic scanning understaged 9 of 12 (75%) patients with proven metastases. Incidental abdominal pathology of clinical significance was documented in 4 patients (2.3%), including 2 with renal cell cancers, 1 with colon cancer, and 1 with a large (8 cm) abdominal aortic aneurysm. Prostate-specific antigen levels in patients with metastatic lymph nodes ranged from 0.7 to 130 ng/mL (Hybritech Tandem assay), with a mean level of 42 ng/mL. Although 9 of 33 patients (27.3%) with PSA levels greater than 25 ng/mL had node metastases, only 3 of these 33 patients (9.1%) were correctly diagnosed by CT scanning.

CONCLUSIONS

Although additional numbers of patients with high PSA levels need to be evaluated, we could not find any justification for routine preoperative CT scanning in patients with a PSA of less than 25 ng/mL. These results suggest that significant savings can be realized by abandoning the practice of routine CT scanning for lymph node metastasis in all patients with newly diagnosed prostate cancer.

Characterization of postcardiac transplant lymphomas. Histology, immunophenotyping, immunohistochemistry, and gene rearrangement

OBJECTIVE

Between 2% and 9% of cardiac transplant recipients develop posttransplant lymphoproliferative disease, which includes lymphomas. These are usually aggressive Epstein-Barr virus-associated B-cell proliferations similar to those seen in other immunodeficiency states. A retrospective pathologic study of the tumor tissue from 21 cardiac transplant recipients with posttransplant lymphoproliferative disease was undertaken.

DESIGN

Tumor histology, immunohistochemistry, immunophenotyping, and DNA analysis for clonal gene rearrangement and the presence of Epstein-Barr virus DNA were performed.

PATIENTS

The mean patient age was 53.4 +/- 10.2 years (range 33-67 years); 33% of the patients were alive at the time of study.

RESULTS

Histologically, the samples comprised one Burkitt's lymphoma, three diffuse mixed lymphomas, eight diffuse large-cell lymphomas, and nine immunoblastic lymphomas. Thirteen (93%) of 14 samples were infiltrated by small reactive T cells; five of the lymphomas qualified as T-cell rich. Of 14 cases studied, 12 had clonal immunoglobulin gene rearrangements, 1 had oligoclonal bands, and 1 exhibited only a germline pattern. The B cells were CD10+, CD19+, and CD20+, and the reactive T cells were CD2+, CD3+, CD5+, CD7+, CD8+, and CD57+ by immunophenotyping.

CONCLUSIONS

In this patient series, morphologically aggressive lymphomas and disseminated disease occurred early as well as late after transplantation. Most of the tumors showed a reactive T-cell component, which may represent a host attempt at controlling the B-cell proliferation.

Neutrophil recruitment after remote scald injury

Thermal injury is one trigger for pulmonary neutrophil recruitment. This article describes the time course of neutrophil recruitment after scald injury. Mice aged 8 to 10 weeks were anesthetized and subjected to 15% topical scald injury. Animals were put to death at 6 hours, 24 hours, 3 days, and 7 days after injury, and the pulmonary tissue harvested for staining with hematoxylin and eosin and neutrophil esterase. Cell counts for neutrophil accumulation were obtained. Control animals were handled in a comparable manner apart from the scald injury. Animals killed at 6 hours demonstrated significant neutrophil recruitment relative to the control. This difference had resolved at 24 hours. Animals killed at 3 and 7 days again demonstrated neutrophil accumulation despite normal behavior and absence of weight change from the control. Quantitative cultures of burn wounds failed to disclose infection. Scald injury was associated with significant pulmonary neutrophil recruitment that resolved at 24 hours. The presence of an untreated wound was associated with neutrophil recruitment beyond 24 hours despite outward normal behavior.

Herpes zoster ophthalmicus and the orbital apex syndrome

Herpes zoster ophthalmicus (HZO) commonly causes isolated ophthalmoplegic syndromes. Visual loss caused by optic neuritis secondary to HZO can be reversible or irreversible. HZO rarely presents as an orbital apex syndrome, when an association with meningo-encephalitis has been reported. We report a case of orbital apex syndrome secondary to HZO treated with systemic steroids and acyclovir. Our patient suffered no systemic complications and displayed a rapid resolution of optic neuropathy. We discuss this case in the light of previous reports and explore the possible pathogenic mechanisms involved.

Binding of monomeric and aggregated immunoglobulin to enzymes. A source of artefact in antibody assays

Pepsinogen has previously been shown to bind non-specifically to immune complexes and aggregated immunoglobulins. We demonstrate here using a solid-phase immunoassay that immunoglobulins aggregated by heat or glutaraldehyde bind non-specifically to several different enzymes. Some of these, including pepsinogen (marketed as pepsin), hyaluronidase and trypsin, are used in the breakdown of tissues or biochemical preparations during the preparation of antigens. Contamination of impure antigens by enzyme is likely to lead to products which bind non-specifically to immune complexes. This can cause misidentification of complexes as antibodies. We recommend that all tests for specific antibody involving the use of antigens prepared by these or other enzymes should include a control with aggregated immunoglobulin substituted for the test serum.

A critical assessment of criteria used in the taxonomy of the genus Rhizopus

Scanning electron microscopy (SEM) and cultural physiology data have been used to assess their taxonomic applicability in delimiting species of the genus Rhizopus. SEM of the sporangiospores of a variety of isolates indicates that there is a continuum of patterns ranging from almost featureless surfaces to verruculose and deeply ridged or striated topologies. The degree of interspecific diversity was sufficient to reduce the diagnostic usefulness of this feature for interspecies delineation. Cultural characteristics, radial growth rate, sporulation pattern, and growth and viability at raised temperatures were also too variable for use in taxonomic studies.