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The role of dynamics in the charge density wave (CDW) phases of 1T-TaS2, especially in accessing metastable phases, is still under scrutiny. We investigated cooling rate dependence on low-temperature CDW phases in this material by scanning tunneling microscopy and x-ray diffraction. In the majority of cases, we found the typical low temperature commensurate CDW and identified no other differences between samples that were fast cooled vs slow cooled from room temperature. In rare cases (1/18 STM experiments and 1/30 XRD experiments), we found a multi-domain structure in the low temperature CDW. The domain structure and metallic behavior revealed by STM and STS measurements of this phase are in excellent agreement with the previously reported metallic mosaic CDW phase. [ABSTRACT FROM AUTHOR]

Background and Aim: The rising incidence of hepatocellular carcinoma (HCC) in Australia is related to increasing rates of metabolic‐associated fatty liver disease (MAFLD). This study aimed to prospectively characterize the metabolic profile, lifestyle, biometric features, and response to treatment of HCC patients in an Australian population. Method: Multicenter prospective cohort analysis of newly diagnosed HCC patients at six multidisciplinary team meetings over a 2‐year period. Results: Three hundred and thirteen (313) newly diagnosed HCC patients with MAFLD (n = 77), MAFLD plus other liver disease (n = 57) (the "mixed" group), and non‐MAFLD (n = 179) were included in the study. Alcohol‐associated liver disease (ALD) (43%) and MAFLD (43%) were the most common underlying liver diseases. MAFLD‐HCC patients were older (73 years vs 67 years vs 63 years), more likely to be female (40% vs 14% vs 20%), less likely to have cirrhosis (69% vs 88% vs 85%), showed higher ECOG, and were less likely to be identified by screening (29% vs 53% vs 45%). Metabolic syndrome was more prevalent in the MAFLD and mixed groups. The severity of underlying liver disease and HCC characteristics were the same across groups. While the MAFLD population self‐reported more sedentary lifestyles, reported dietary patterns were no different across the groups. Dyslipidemia was associated with tumor size, and those taking statins had a lower recurrence rate. Conclusion: Equal to ALD, MAFLD is now the most common underlying liver disease seen in HCC patients in Australia. Future HCC prevention screening and treatment strategies need to take this important group of patients into consideration. [ABSTRACT FROM AUTHOR]

Environmental conditions in estuarine systems are undergoing significant changes resulting from climate change and anthropogenic inputs. Yet, information on how changing conditions structure three-dimensional habitats of living resources is not available for many important species, nor is it known how differences in physiological tolerances between species may influence this habitat volume. Hence, the objective of this study was to apply the habitat volume (HabVol) model in a proof-of-concept exercise to (1) quantify interannual changes in the volume of potential habitat for 12 species of estuarine fish and shellfish, (2) discern which parameters—temperature, salinity, or dissolved oxygen—had the most influence on potential habitat, and (3) identify which species' habitat was most sensitive to environmental variability. Ten years of predictions from a 3D hydrodynamic and dissolved oxygen model of Chesapeake Bay was used with HabVol to estimate daily habitat volumes. Required (constrained by mortality) and optimal (related to growth) habitats were calculated for multiple life stages. The combination of physiological limitations and environmental variability had a wide range of effects that depended on a species' physiological tolerances. While salinity and dissolved oxygen were the primary constraints on required habitat volumes, salinity and temperature had the strongest constraint on optimal habitat volumes. Predictive relationships between physiological tolerances and changes in habitat volumes were identified and could be used to estimate habitat limitation in estuaries where 3D models are unavailable. Results indicate that this habitat volume modeling approach could be used to quantify essential fish habitat and project the influence of climate change and nutrient loading on living resources. [ABSTRACT FROM AUTHOR]

Background and Aims: Irreversible electroporation (IRE) is a non-thermal ablation technique for unresectable hepatocellular carcinoma (HCC) not amenable to standard thermal ablation. The aim of this study was to report our longer-term outcomes using this treatment modality. Method: We identified all patients at our institution who underwent IRE for HCC between December 2008 and October 2019 as recommended after multi-disciplinary team review. Demographic, clinical, tumour response and survival data up until 1 March, 2020 were analysed. The primary outcome was local recurrence-free survival (LRFS) in patients who had a complete response (CR). Secondary outcomes included CR rates, procedure-related complications and the incidence of death or liver transplantation. Results: A total of 23 patients (78% males, median age 65.2 years) received IRE therapy to 33 HCC lesions during the study period with the median tumour size being 2.0 cm (range 1.0–5.0 cm). Twenty-nine (87.9%) lesions were successfully ablated after one (n = 26) or two (n = 3) procedures. The median follow-up time for these lesions was 20.4 months. The median overall LRFS was 34.5 (95% CI 24.8 -) months with a 6- and 12-month LRFS of 87.9% (95% CI 75.8–100) and 83.6% (95% CI 70.2–99.7), respectively. Tumours < 2 cm had a 12-month LRFS of 100% (95% CI 100–100). Conclusion: IRE appears to be an efficacious local ablative method for early stage HCC not amenable to standard ablative techniques, with very good CR rates and longer-term LRFS, particularly for smaller lesions. Further studies comparing this technique to more widely accepted ablative methods such as radiofrequency and microwave ablation are warranted. [ABSTRACT FROM AUTHOR]

Estuaries represent the primary linkage between the terrestrial and marine carbon cycles, and estuarine processing of riverine and coastal carbon plays a disproportionately large role in the global carbon cycle relative to the small areal extent of the estuarine environments. However, knowledge of the rate of organic carbon deposition and burial in estuarine sediments is lacking at regional scales. Data on surficial total organic carbon, linear sedimentation, and bulk density of estuarine sediments were compiled and categorized via a cluster analysis in order to estimate carbon deposition within the contiguous United States (CONUS). The cluster analysis broadly grouped estuaries by geography, but exceptions to geographic clustering highlighted differences within regions. A transfer function from deposition to burial based on linear sedimentation rate was used to estimate burial efficiency, and thus the rate of carbon burial within each cluster. We estimate organic carbon deposition rates within CONUS estuarine sediments to be 161 [121–217, 95% confidence] g C/m2/yr with a burial efficiency estimated at 38 [34–42, 95% confidence] %, which yields a long‐term burial rate of 64 [44–97, 95% confidence] g C/m2/yr. Spatially integrated organic deposition and burial rates are 11.3 [8.5–15.2, 95% confidence] and 4.5 [3.1–6.8, 95% confidence] Tg C/yr, respectively. Our findings allow a more thorough understanding of coastal carbon cycling, which is critical for both management purposes as well as for the assessment of the role of estuaries in past and future climate change. Plain Language Summary: Estuaries are diverse ecosystems located at the coastal mouth of rivers or within embayments, where terrestrial and marine environments meet. Estuaries tend to be highly productive and provide many critical ecosystem services for their communities. Carbon‐based material delivered primarily by rivers or produced by aquatic organisms is deposited within the sediments of estuaries. Organisms in sediments consume some of the deposited material and respire it principally as carbon dioxide. However, a portion is buried within deeper sediments and is removed from the contemporary carbon cycle. The rate of material deposited and ultimately buried can influence the function of the estuary as well as its relation to communities and the adjacent coastal ecosystems. On longer time scales (many thousands of years), this removal can also influence the global carbon cycle. We grouped estuaries based on their physical and chemical characteristics and estimated sediment deposition and burial rates for the contiguous United States, where we found that approximately 40% of deposited material was buried within sediments. Key Points: Sedimentation processes in estuaries within the contiguous United States are estimated to deposit 11.3 [8.5–15.2, 95% confidence] Tg of carbon per yearRemineralization liberates a significant portion of deposited carbon, yielding centennial‐scale burial of 4.5 [3.1–6.8, 95% confidence] Tg carbon per yearEstuaries of the contiguous United States are classified into six clusters based on geospatial and biogeochemical characteristics using k‐means analysis [ABSTRACT FROM AUTHOR]

The carbon cycle in estuarine environments is difficult to quantify because of substantial spatiotemporal heterogeneity in the sources, exchanges, and fates of carbon. We overcame these challenges with a multidecade numerical modeling analysis of seasonal, interannual, and decadal variability in net ecosystem metabolism (NEM) and associated carbon fluxes in Chesapeake Bay. Interannual variability in NEM along the estuarine axis indicated a clear spatial dependency of NEM on riverine discharge, with elevated flows causing increasing upper bay heterotrophy and increasing lower bay autotrophy during wet years. Our 30‐year simulation suggested the Chesapeake Bay is somewhat unique among estuaries in its tendency toward net autotrophy as a consequence of its extremely high nutrient to organic matter input ratio and large size. Budgets of three different carbon pools revealed that the entire Chesapeake Bay is a CO2 source to the atmosphere and organic carbon source to the open shelf, providing quantitative export estimates for interpretation of anthropogenic perturbations to the regional carbon flux. Key Points: A clear spatial dependency of net ecosystem metabolism on river flow was observed in Chesapeake BayThe Chesapeake Bay is unique in its tendency toward net autotrophy due to its extremely high nutrient to organic matter input ratioThis study provides key quantitative export estimates for the interpretation of anthropogenic perturbations to the regional carbon flux [ABSTRACT FROM AUTHOR]

A central organizing concept in estuarine biogeochemistry is net ecosystem production (NEP). However, estimates of seasonal and interannual variability of whole-system estuarine NEP, which provide insight into how estuaries respond to climatic and anthropogenic forcing, are rare. The main objectives of this study are to (1) determine the seasonal and interannual variability in whole-system NEP of Biscayne Bay, a subtropical, shallow estuary located in southeastern Florida, USA, and (2) determine the potential driving mechanisms of NEP in this estuary. We compute monthly NEP over more than 12 years by constructing the dissolved oxygen budget for the estuary from monthly snapshot oxygen survey data (i.e., collected once per month). High-frequency observations of oxygen in similar subtropical estuaries were used to quantify the error associated with the snapshot monthly sampling. Oxygen air-water exchange and NEP closely balanced each other, with the long-term mean NEP (± 2 standard errors) equal to − 5.3 ± 0.3 mol O2 m−2 year−1, indicating net heterotrophy. Significant seasonality was found, with lowest NEP in September. At monthly time scales, NEP was significantly positively correlated with chlorophyll and total phosphorus and significantly negatively correlated with canal flow. Interannual variability in NEP was substantial, and the bay temporarily shifted from net heterotrophy to net autotrophy after the 2005 Atlantic hurricane season, probably in response to increases in nutrients from runoff and resuspension. These findings show that monthly oxygen surveys can be used to quantify whole-system estuarine NEP and that Biscayne Bay NEP is sensitive to climatic and anthropogenic forcing on seasonal and interannual timescales. [ABSTRACT FROM AUTHOR]

The study of acidification in Chesapeake Bay is challenged by the complex spatial and temporal patterns of estuarine carbonate chemistry driven by highly variable freshwater and nutrient inputs. A new module was developed within an existing coupled hydrodynamic‐biogeochemical model to understand the underlying processes controlling variations in the carbonate system. We present a validation of the model against a diversity of field observations, which demonstrated the model's ability to reproduce large‐scale carbonate chemistry dynamics of Chesapeake Bay. Analysis of model results revealed that hypoxia and acidification were observed to cooccur in midbay bottom waters and seasonal cycles in these metrics were regulated by aerobic respiration and vertical mixing. Calcium carbonate dissolution was an important buffering mechanism for pH changes in late summer, leading to stable or slightly higher pH values in this season despite persistent hypoxic conditions. Model results indicate a strong spatial gradient in air‐sea CO2 fluxes, where the heterotrophic upper bay was a strong CO2 source to atmosphere, the mid bay was a net sink with much higher rates of net photosynthesis, and the lower bay was in a balanced condition. Scenario analysis revealed that reductions in riverine nutrient loading will decrease the acid water volume (pH < 7.5) as a consequence of reduced organic matter generation and subsequent respiration, while bay‐wide dissolved inorganic carbon (DIC) increased and pH declined under scenarios of continuous anthropogenic CO2 emission. This analysis underscores the complexity of carbonate system dynamics in a productive coastal plain estuary with large salinity gradients. Key Points: A new carbonate chemistry module was developed to understand the underlying processes controlling variations in the carbonate systemModel results revealed that seasonal cycles of acidification in midbay bottom waters was regulated by aerobic respiration and vertical mixingScenario analysis revealed that reductions in riverine nutrient loading will decrease the acid water volume [ABSTRACT FROM AUTHOR]

A three‐decade time series of solute concentrations was combined with a box‐modeling system to analyze long‐term trends in the concentration, production, and transport of dissolved inorganic nitrogen species along the mainstem axis of Chesapeake Bay. Water‐ and salt‐balance calculations associated with box‐modeling provided regional, seasonal, and interannual estimates of net advective and nonadvective transport and net biogeochemical production rates for oxygen and dissolved nitrogen. The strongest decadal trends were observed for decreasing late‐summer ammonium concentrations in bottom layers from brackish to polyhaline bay regions. Contemporaneous trends of increasing late‐summer bottom‐layer dissolved oxygen (O2) concentration were consistent with the observed NH4+ patterns, suggesting that increasing dissolved O2 levels may also reflect declining bottom respiration and drive nitrogen loss via increased rates of coupled nitrification–denitrification. Significant (but weaker) trends of increasing nitrate plus nitrite (NO2+3−) concentration and net production were consistent with the notion that increased nitrification may be stimulated by increasing dissolved O2 concentrations. Sorting bottom water NH4+ and NO2+3− net production rates into two pools (before and after the year 2000) revealed that general seasonal patterns were similar, but recent NH4+ net production rates were consistently lower and NO2+3− and NO2− rates higher in summer and fall compared to earlier years, especially in the middle Bay regions. We conclude that late‐season replenishment of oxygen associated with declining nutrient loads induced a negative feedback process, whereby decreased hypoxia suppressed NH4+ recycling and created conditions favorable for additional nitrogen loss via coupled nitrification–denitrification. [ABSTRACT FROM AUTHOR]

Cu(In, Ga)Se[sub 2]/CdS/ZnO thin-film solar cells were exposed to doses up to 5×10[sup 8] rad(Si) of 50 keV x rays. Device performance consistently showed very little degradation, implying that previously observed radiation-induced performance reductions were likely the result of displacement damage. Subsequent experiments showed that cells recovered to near beginning-of-life performance with only short anneals under 50 °C. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here we construct such a budget for eastern North America using historical data, empirical models, remote sensing algorithms, and process‐based models. Considering the net fluxes of total carbon at the domain boundaries, 59 ± 12% (± 2 standard errors) of the carbon entering is from rivers and 41 ± 12% is from the atmosphere, while 80 ± 9% of the carbon leaving is exported to the open ocean and 20 ± 9% is buried. Net lateral carbon transfers between the three main ecosystem types are comparable to fluxes at the domain boundaries. Each ecosystem type contributes substantially to exchange with the atmosphere, with CO2 uptake split evenly between tidal wetlands and shelf waters, and estuarine CO2 outgassing offsetting half of the uptake. Similarly, burial is about equal in tidal wetlands and shelf waters, while estuaries play a smaller but still substantial role. The importance of tidal wetlands and estuaries in the overall budget is remarkable given that they, respectively, make up only 2.4 and 8.9% of the study domain area. This study shows that coastal carbon budgets should explicitly include tidal wetlands, estuaries, shelf waters, and the linkages between them; ignoring any of them may produce a biased picture of coastal carbon cycling. [ABSTRACT FROM AUTHOR]

Summary: Background: Non‐alcoholic fatty liver disease (NAFLD) is a significant disease burden in obesity. Liver fibrosis is an important prognostic factor in NAFLD, and detection is vital. The pathophysiological changes of obesity can alter the accuracy of non‐invasive NAFLD tests. We aimed to review current evidence for common non‐invasive tests for NAFLD‐related fibrosis in obesity. Methods: We systematically searched for studies assessing the diagnostic accuracy of 11 biomarker panels and elastography techniques for NAFLD‐related fibrosis in obesity. Meta‐analyses were performed where possible. Results: Thirty‐eight studies were identified assessing the selected tests in obese populations. Simple biomarker panels (e.g. NAFLD fibrosis score) were the most validated. Evidence showed better accuracy of complex biomarker panels (NAFLD fibrosis score: summary receiver operator characteristic [SROC] 0.795–0.813 vs. enhanced liver fibrosis: SROC 0.962); however, these were poorly validated in obesity. Elastography techniques were better studied and had high diagnostic accuracy (transient elastography: SROC 0.859; magnetic resonance elastography: SROC 0.965) but were limited by BMI‐dependent failure. Limited evidence was found to validate the accuracy of any test in exclusively obese populations. Conclusion: In obese subjects, complex biomarker panels and elastography have been reasonable to good accuracy for NAFLD‐related fibrosis; however, these methods have not been well validated. Further study in this high‐risk population is needed. [ABSTRACT FROM AUTHOR]

Submersed plants are sensitive to nutrient loading because excess algal growth creates light-limiting conditions. However, submersed plant beds can also modify nutrient cycling through feedback loops whereby algal growth is limited and plant growth is enhanced. Whereas most studies on the effect of submersed aquatic vegetation (SAV) beds on nutrient cycling concentrate on either biogeochemical or physical controlling mechanisms, we use a holistic approach that analyzes how these processes interact. We measured a suite of physical and biological processes in a large SAV bed and developed a simple, 1-dimensional reactive transport model to investigate the mechanisms underlying SAV bed effects on nutrient cycling. We observed lower water column concentrations of dissolved inorganic nitrogen and phosphorus (DIN and DIP) inside relative to outside the SAV bed during the summer. Sediment denitrification (mean N-N flux in August = 46 μmol m h) and plant nutrient assimilation (August rates =385 μmol N and 25 μmol P m h) were mechanisms of nutrient removal. We also found that the physical structure of the bed decreased advection and tidal dispersion, resulting in increased water residence time that enhanced biologically mediated nutrient loss. These processes create conditions that enable SAV to outcompete other primary producers, as water column nutrient concentrations were low enough to limit algal growth and associated light attenuation, while sediment pore water concentrations were sufficient to satisfy SAV nutrient demand. These findings suggest that interactions between physical and biological feedback processes in SAV beds can play a key role in structuring shallow aquatic ecosystems. [ABSTRACT FROM AUTHOR]

While HBV and HCV are risk factors for HCC, uncertainty exists as to whether these viral infections have prognostic significance in HCC. Thus, we compared the overall survival of patients with HBV, HCV and nonviral HCC, and evaluated whether the presence of HBV and HCV predicts patient outcomes. We conducted a multicentre study of HCC cases diagnosed at six Melbourne tertiary hospitals between Jan 2000-Dec 2014. Patient demographics, liver disease and tumour characteristics and patient outcomes were obtained from hospital databases, computer records and the Victorian Death Registry. Survival outcomes were compared between HBV, HCV and nonviral hepatitis cases and predictors of survival determined using Cox proportional hazards regression. There were 1436 new HCC cases identified including 776 due to viral hepatitis ( HBV 235, HCV 511, HBV- HCV 30) and 660 from nonviral causes. The median survival of HBV, HCV and nonviral HCC patients was 59.1, 28.4 and 20.9 months, respectively ( P<.0001). On multivariate analysis, independent risk factors for survival included HCC aetiology, gender, BCLC stage, serum AFP, total number and size of lesions, and serum creatinine and albumin. After adjusting for these and method of detection, HBV remained an independent predictor of improved overall survival when compared to both nonviral ( HR 0.60%, 95% CI 0.35-0.98; P=.03) and HCV-related HCC ( HR 0.51%, 95% CI 0.30-0.85; P=.01). In this large multicentre study, HBV is independently associated with improved overall survival compared with HCV and nonviral-related HCC. Further studies are needed to determine the underlying factor(s) responsible. [ABSTRACT FROM AUTHOR]

Purpose: To establish a preoperative decision model for accurate indication of systemic therapy in early-stage breast cancer using multiparametric MRI at 7-tesla field strength. Materials and methods: Patients eligible for breast-conserving therapy were consecutively included. Patients underwent conventional diagnostic workup and one preoperative multiparametric 7-tesla breast MRI. The postoperative (gold standard) indication for systemic therapy was established from resected tumor and lymph-node tissue, based on 10-year risk-estimates of breast cancer mortality and relapse using Adjuvant! Online. Preoperative indication was estimated using similar guidelines, but from conventional diagnostic workup. Agreement was established between preoperative and postoperative indication, and MRI-characteristics used to improve agreement. MRI-characteristics included phospomonoester/phosphodiester (PME/PDE) ratio on 31-phosphorus spectroscopy (31P-MRS), apparent diffusion coefficients on diffusion-weighted imaging, and tumor size on dynamic contrast-enhanced (DCE)-MRI. A decision model was built to estimate the postoperative indication from preoperatively available data. Results: We included 46 women (age: 43-74yrs) with 48 invasive carcinomas. Postoperatively, 20 patients (43%) had positive, and 26 patients (57%) negative indication for systemic therapy. Using conventional workup, positive preoperative indication agreed excellently with positive postoperative indication (N = 8/8; 100%). Negative preoperative indication was correct in only 26/38 (68%) patients. However, 31P-MRS score (p = 0.030) and tumor size (p = 0.002) were associated with the postoperative indication. The decision model shows that negative indication is correct in 21/22 (96%) patients when exempting tumors larger than 2.0cm on DCE-MRI or with PME>PDE ratios at 31P-MRS. Conclusions: Preoperatively, positive indication for systemic therapy is highly accurate. Negative indication is highly accurate (96%) for tumors sized ≤2,0cm on DCE-MRI and with PME≤PDE ratios on 31P-MRS. [ABSTRACT FROM AUTHOR]

The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in middepths where acids are generated as a result of H2S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO2 uptake, and CO2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary. [ABSTRACT FROM AUTHOR]

Economic valuation of ecological restoration most often encompasses only the most tangible ecosystem service benefits, thereby omitting many difficult-to-measure benefits, including those derived from enhanced reliability of ecosystem services. Because climate change is likely to impose novel ecosystem stressors, a typical approach to valuing benefits may fail to capture the contribution of ecosystem resilience to sustaining long-term benefits. Unfortunately, we generally lack predictive probabilistic models that would enable measurement and valuation of resilience. Therefore, alternative measures are needed to complement monetary values and broaden understanding of restoration benefits. We use a case study of Chesapeake Bay restoration (total maximum daily load) to show that ecosystem service benefits that are typically monetized leave critical information gaps. To address these gaps, we review evidence for ecosystem services that can be quantified or described, including changes in harmful algal bloom risks. We further propose two integrative indicators of estuarine resilience-the extent of submerged aquatic vegetation and spatial distribution of fish. Submerged aquatic vegetation extent is indicative of qualities of ecosystems that promote positive feedbacks to water quality. Broadly distributed fish populations reduce risk by promoting diverse responses to spatially heterogeneous stresses. Our synthesis and new analyses for the Chesapeake Bay suggest that resilience metrics improve understanding of restoration benefits by demonstrating how nutrient and sediment load reductions will alleviate multiple sources of stress, thereby enhancing the system's capacity to absorb or adapt to extreme events or novel stresses. [ABSTRACT FROM AUTHOR]

Estuarine ecosystem ecology is a dynamic field of study that has historically focused on a spectrum of compelling research topics, and here we present a series of perspectives on the major challenges to be overcome and key research questions to be addressed toward making progress over the coming decades. The challenges we identify include (1) maintaining and improving spatially distributed time-series datasets, (2) maximizing innovation by harnessing new technologies, (3) resuscitating experimental ecosystem research for estuaries, (4) integrating diagnostic ecological models into ecosystem research, and (5) improving basic science by linking it to applied research. We also raise a number of key research questions for the field, including (1) how does food web function respond to changing climate and nutrients, (2) what are likely trajectories of ecosystem recovery in response to restoration, (3) how does climate alter seasonality of estuarine ecosystem processes, (4) how do estuaries affect the global carbon budget and what are key feedbacks, and (5) how will tidal wetland ecosystems respond to sea level rise and climate change? Looking ahead, we envision that the field of estuarine ecosystem ecology will continue to build upon its rich tradition to address fundamental research questions with an expanded toolkit and enlightened perspective to focus basic science on the knowledge needs of society. [ABSTRACT FROM AUTHOR]

There is a growing emphasis on preserving ecological resilience, or a system's capacity to absorb or recover quickly from perturbations, particularly in vulnerable coastal regions. However, the factors that affect resilience to a given disturbance are not always clear and may be system-specific. We analyzed and synthesized time series datasets to explore how extreme events impacted a large system of submersed aquatic vegetation (SAV) in upper Chesapeake Bay and to identify and understand associated mechanisms of resilience. We found that physical removal of plants around the edge of the bed by high flows during a major flood event as well as subsequent wind-driven resuspension of newly deposited sediment and attendant light-limiting conditions were detrimental to the SAV bed. Conversely, it appears that the bed attenuated high flows sufficiently to prevent plant erosion at its inner core. The bed also attenuated wind-driven wave amplitude during seasonal peaks in plant biomass, thereby decreasing sediment resuspension and increasing water clarity. In addition, clear water appeared to 'spill over' into adjacent regions during ebb tide, improving the bed's capacity for renewal by creating more favorable growing conditions in areas where plant loss had occurred. These analyses demonstrate that positive feedback processes, whereby an SAV bed modifies its environment in ways that improve its own growth, likely serve as mechanisms of SAV resilience to flood events. Although this work focuses on a specific system, the synthetic approach used here can be applied to any system for which routine monitoring data are available. [ABSTRACT FROM AUTHOR]

Widespread use of ultrahigh-field 31P MRSI in clinical studies is hindered by the limited field of view and non-uniform radiofrequency (RF) field obtained from surface transceivers. The non-uniform RF field necessitates the use of high specific absorption rate (SAR)-demanding adiabatic RF pulses, limiting the signal-to-noise ratio (SNR) per unit of time. Here, we demonstrate the feasibility of using a body-sized volume RF coil at 7 T, which enables uniform excitation and ultrafast power calibration by pick-up probes. The performance of the body coil is examined by bench tests, and phantom and in vivo measurements in a 7-T MRI scanner. The accuracy of power calibration with pick-up probes is analyzed at a clinical 3-T MR system with a close to identical 1H body coil integrated at the MR system. Finally, we demonstrate high-quality three-dimensional 31P MRSI of the human body at 7 T within 5 min of data acquisition that includes RF power calibration. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A coupled hydrodynamic-dissolved oxygen model is developed to simulate the seasonal cycle of dissolved oxygen (DO) in Chesapeake Bay and investigate processes regulating summer hypoxia in the estuary. A budget analysis of DO in the bottom water reveals a balance between physical transport and biological consumption. In addition to the vertical diffusive flux, the longitudinal and vertical advective fluxes are important suppliers of DO to the bottom water. The longitudinal advective flux is affected not only by gravitational circulation but also by wind-driven currents. The vertical advective flux is affected by wind-driven lateral circulation and shows a strong dependence on wind speed and direction. Up-estuary winds weaken the landward bottom flow and generate a clockwise lateral circulation that exchanges DO between the deep channel and adjacent shoals, thereby reducing the longitudinal advective flux and increasing the vertical advective flux. In contrast, down-estuary winds amplify the longitudinal flux and reduce the vertical flux. During the summer, water column respiration contributes to about 74 % of the total biological consumption and sediment oxygen demand accounts for about 26 %. Sensitivity analysis model runs are conducted to analyze how changing river flows and winds affect the hypoxia prediction and oxygen budget balance. Due to the compensating changes in longitudinal and vertical fluxes, the hypoxic volume is relatively insensitive to changes in the river flow. In contrast, the timing and size of hypoxic volume changes with wind speed. Sensitivity analysis also shows that plankton oxygen production, water column respiration, and sediment oxygen demand all affect the hypoxia prediction and bottom oxygen balance. [ABSTRACT FROM AUTHOR]

Time Differential Perturbed Angular Correlations (TDPAC) studies, supported by Density Functional Theory (DFT) modelling, have shown that palladium atoms in silicon and germanium pair with vacancies. Building on these results, here we present DFT predictions and some tentative TDPAC results on palladium-defect complexes and site locations of palladium impurities in diamond and silicon carbide. For both diamond and silicon carbide, the DFT calculations predict that a split-vacancy V-PdBI-V complex is favoured, with the palladium atom on a bond-centred interstitial site having a nearest-neighbour semi-vacancy on either side. Consistent with experimental results, this configuration is also assigned to palladium complexes in silicon and germanium. For silicon carbide, the DFT modelling predicts furthermore that a palladium atom in replacing a carbon atom moves to a bond-centred interstitial site and pairs with a silicon vacancy to form a complex that is more stable than that of a palladium atom which replaces a silicon atom and then moves to a bond-centred interstitial site pairings with a carbon vacancy. These two competing alternatives differ by 8.94 eV. The favourable pairing with a silicon vacancy is also supported independently by TRIM Monte Carlo calculations, which predict that more silicon vacancies than carbon vacancies are created during heavy ion. implantation. [ABSTRACT FROM AUTHOR]

Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic carbon, and carbon burial in the sediment to estuarine water residence time and total nitrogen input across the landward boundary. Output from a data-constrained water quality model was used to estimate inputs of total nitrogen and organic carbon to the estuaries across the landward boundary, including fluvial and tidal-wetland sources. Organic carbon export from the estuaries to the continental shelf was computed by difference, assuming steady state. Uncertainties in the budget were estimated by allowing uncertainties in the supporting model relations. Collectively, U.S. East Coast estuaries are net heterotrophic, with the area-integrated NEP of −1.5 (−2.8, −1.0) Tg C yr−1 (best estimate and 95% confidence interval) and area-normalized NEP of −3.2 (−6.1, −2.3) mol C m−2 yr−1. East Coast estuaries serve as a source of organic carbon to the shelf, exporting 3.4 (2.0, 4.3) Tg C yr−1 or 7.6 (4.4, 9.5) mol C m−2 yr−1. Organic carbon inputs from fluvial and tidal-wetland sources for the region are estimated at 5.4 (4.6, 6.5) Tg C yr−1 or 12 (10, 14) mol C m−2 yr−1 and carbon burial in the open estuarine waters at 0.50 (0.33, 0.78) Tg C yr−1 or 1.1 (0.73, 1.7) mol C m−2 yr−1. Our results highlight the importance of estuarine systems in the overall coastal budget of organic carbon, suggesting that in the aggregate, U.S. East Coast estuaries assimilate (via respiration and burial) ~40% of organic carbon inputs from fluvial and tidal-wetland sources and allow ~60% to be exported to the shelf. [ABSTRACT FROM AUTHOR]

Portal hypertension is an important complication of liver disease. As a result of elevated pressures within the portal vein several complications can arise, including the development of oesophageal and gastric varices, ascites, hepatic encephalopathy as well as complications secondary to circulatory dysfunction, such as hepatorenal syndrome, portopulmonary syndrome and hepatopulmonary syndrome. This review outlines the pathogenesis and diagnosis of portal hypertension and outlines the management of these various important clinical sequelae. The management of oesophageal and gastric varices is particularly important, and both the emergency management together with prophylactic management of this condition are described. [ABSTRACT FROM AUTHOR]

Although seasonal hypoxia is a well-studied phenomenon in many coastal systems, most previous studies have only focused on variability and controls on low-oxygen water masses during warm months when hypoxia is most extensive. Surprisingly, little attention has been given to investigations of what controls the development of hypoxic water in the months leading up to seasonal oxygen minima in temperate ecosystems. Thus, we investigated aspects of winter-spring oxygen depletion using a 25-year time series (1985-2009) by computing rates of water column O depletion and the timing of hypoxia onset for bottom waters of Chesapeake Bay. On average, hypoxia (O <62.5 μM) initiated in the northernmost region of the deep, central channel in early May and extended southward over ensuing months; however, the range of hypoxia onset dates spanned >50 days (April 6 to May 31 in the upper Bay). O depletion rates were consistently highest in the upper Bay, and elevated Susquehanna River flow resulted in more rapid O depletion and earlier hypoxia onset. Winter-spring chlorophyll a concentration in the bottom water was highly correlated with interannual variability in hypoxia onset dates and water column O depletion rates in the upper and middle Bay, while stratification strength was a more significant driver in the timing of lower Bay hypoxia onset. Hypoxia started earlier in 2012 (April 6) than previously recorded, which may be related to unique climatic and biological conditions in the winter-spring of 2012, including the potential carryover of organic matter delivered to the system during a tropical storm in September 2011. In general, mid-to-late summer hypoxic volumes were not correlated to winter-spring O depletion rates and onset, suggesting that the maintenance of summer hypoxia is controlled more by summer algal production and physical forcing than winter-spring processes. This study provides a novel synthesis of O depletion rates and hypoxia onset dates for Chesapeake Bay, revealing controls on the phenology of hypoxia development in this estuary. [ABSTRACT FROM AUTHOR]

Here, we show that the sensitivity of 31P MRSI of 31P spins J-coupled to protons can be increased by almost a factor of three when compared with an optimal direct detection free induction decay. By direct detection integrated with multi-echo polarization transfer (DIMEPT), multiple signals from polarization transfer and direct detection can be acquired in one repetition time, with minimal mutual interference, provided that the number of refocusing pulses in the multi-echo polarization transfer part is even. The DIMEPT sequence was implemented on a 7-T body scanner and tested on a phantom and on the breasts of five healthy volunteers. The in vivo signal-to-noise ratio (SNR) enhancement for the J-coupled phosphomonoesters was 270% when compared with an Ernst angle pulse-acquire sequence. However, the phosphodiester signals, presumably mainly mobile phospholipids, had T2 values that were too short to be enhanced. Uncoupled 31P spins, with sufficiently long T2 values, such as inorganic phosphate, were SNR enhanced by a factor of 1.9 relative to an Ernst-angle excitation pulse-acquire sequence by multi-echo direct detection. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Phosphorus metabolite ratios are potential biomarkers in breast cancer diagnosis and treatment monitoring. Our purpose was to investigate the metabolite ratios phosphomonoester to phosphodiester, phosphoethanolamine (PE) to glycerophosphoethanolamine (GPE), and phosphocholine (PC) to glycerophosphocholine (GPC) in glandular breast tissue, and the potential effect of the menstrual cycle, using P magnetic resonance spectroscopy (MRS) at 7T. Seven women with regular menstrual cycles each underwent four examinations using a 3D P multi-echo magnetic resonance spectroscopic imaging sequence. Peak integrals were assessed using IDL and JMRUI software. First, T2 relaxation times were calculated using multi-echo data pooled across subjects and time points. Subsequent, metabolite ratios were calculated for each phase of the menstrual cycle using the calculated T2 values to account for when combining the free induction decay and all five echoes. The metabolite ratios were calculated both on group level and individually. T2 decay fits resulted in a T2 relaxation time for PE of 154 ms (95 % CI 144-164), for PC of 173 ms (95 % CI 148-205), for Pi of 188 ms (95 % CI 182-193), for GPE of 48 ms (95 % CI 44-53), and for GPC of 23 ms (95 % CI 21-26). The metabolite ratios analyzed on group level showed negligible variation throughout the menstrual cycle. Individual results did show an apparent intra-individual variation; however, not significant due to the measurements' uncertainty. To conclude, phospholipids in glandular tissue as measured with P MRS at 7 T are not significantly affected by the menstrual cycle. [ABSTRACT FROM AUTHOR]

In Australia prior to 1992, many patients with bleeding disorders were exposed to hepatitis C through blood products. However, the incidence, complications and response to treatment of chronic hepatitis C ( CHC) in this population are poorly characterized. The aim of this study was to examine the prevalence of CHC and response to treatment in an Australian bleeding disorders population. Demographic data, virological data and liver disease status from these 700 patients with inherited bleeding disorders were analysed. Of these 700 patients, 424 (61%) had been tested for CHC infection and 219 (52%) were hepatitis C antibody positive, with the prevalence approaching 100% in patients with severe bleeding disorders. Of 219 patients, 73 (33%) had received treatment for their infection with a response rate of 33/73 (45%) across all genotypes. Of 219 patients, 34 (16%) had spontaneous viral clearance. When measured with transient elastography, 44/98 (45%) patients with CHC had significant liver fibrosis and 15/98 (15%) had liver cirrhosis. Of 130 patients, 38 (29%) with CHC infection had no evidence of follow-up with an appropriate clinician in the past 2 years. This study demonstrates that testing for CHC in this population is incomplete and treatment rates are low. Given the substantial morbidity and mortality associated with CHC and new therapeutic options becoming available, it seems important to reengage patients to diagnose, offer treatment and monitor this infection. [ABSTRACT FROM AUTHOR]

An adiabatic multi-echo spectroscopic imaging (AMESING) sequence, used for 31P MRSI, with spherical k-space sampling and compensated phase-encoding gradients, was implemented on a whole-body 7-T MR system. One free induction decay (FID) and up to five symmetric echoes can be acquired with this sequence. In tissues with low T2* and high T2, this can theoretically lead to a potential maximum signal-to-noise ratio (SNR) increase of almost a factor of three, compared with a conventional FID acquisition with Ernst-angle excitation. However, with T2 values being, in practice, ≤400 ms, a maximum enhancement of approximately two compared with low flip Ernst-angle excitation should be feasible. The multi-echo sequence enables the determination of localized T2 values, and was validated with 31P three-dimensional MRSI on the calf muscle and breast of a healthy volunteer, and subsequently applied in a patient with breast cancer. The T2 values of phosphocreatine, phosphodiesters (PDE) and inorganic phosphate in calf muscle were 193 ± 5 ms, 375 ± 44 ms and 96 ± 10 ms, respectively, and the apparent T2 value of γ-ATP was 25 ± 6 ms. A T2 value of 136 ± 15 ms for inorganic phosphate was measured in glandular breast tissue of a healthy volunteer. The T2 values of phosphomonoesters (PME) and PDE in breast cancer tissue (ductulolobular carcinoma) ranged between 170 and 210 ms, and the PME to PDE ratios were calculated to be phosphoethanolamine/glycerophosphoethanolamine = 2.7, phosphocholine/glycerophosphocholine = 1.8 and PME/PDE = 2.3. Considering the relatively short T2* values of the metabolites in breast tissue at 7 T, the echo spacing can be short without compromising spectral resolution, whilst maximizing the sensitivity. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The risk of bleeding in patients with hereditary bleeding disorders ( HBD) undergoing gastro-intestinal ( GI) endoscopic procedures is unknown but guidelines generally recommend correction of factor deficiency. Investigate the safety of oral tranexamic acid ( TA) without prophylactic factor replacement to prevent bleeding complications in patients with HBD undergoing elective GI endoscopic procedures. A prospective single-arm pilot study testing the feasibility of using TA, without prophylactic factor replacement or desmopressin preprocedure, for prevention of bleeding complications following elective standard risk (<1% risk of bleeding) endoscopic procedures in patients with HBD. Baseline factor levels, haemoglobin and iron studies ( IS) were measured preprocedure. Primary outcome of bleeding ( NCI CTCAE v3.0 Bleeding Scale) was undertaken by patient review and repeat Hb, IS on day 21. Twenty-eight patients underwent 32 GI endoscopic procedures from September 2010 until June 2012. The median age was 53 years (range 24-75 years) and disease types included mild haemophilia A/B ( n = 12), severe haemophilia A/B ( n = 9), von Willebrand disease ( n = 5), FXI deficiency ( n = 1) and FVII deficiency ( n = 1). Procedures performed included 11 gastroscopies, 12 colonoscopies, 8 gastroscopies and colonoscopies and 1 flexible sigmoidoscopy. Fourteen standard risk procedures and two high risk procedures were performed. Two patients experienced Grade 1 bleeding and one patient experienced Grade 2 bleeding. This study suggests that TA without prophylactic factor replacement may be a safe approach for mild and moderate HBD patients undergoing standard risk endoscopic procedures, particularly where no biopsy is performed. These findings should be confirmed in a larger study. [ABSTRACT FROM AUTHOR]

Background Chronic hepatitis B ( HBV) and cirrhosis are major risk factors for hepatocellular carcinoma ( HCC). The proportion and characteristics of cases with cirrhosis are not well documented. Aim Our aim was to compare demographic, viral and tumour characteristics of HBV-associated HCC in an Australian cohort, in patients with and without cirrhosis. Methods Existing HCC databases at six Melbourne teaching hospitals were reviewed for cases associated with HBV. Patient demographics, HBV viral characteristics, presence of cirrhosis, serum alpha-fetoprotein and tumour size were assessed. Mode of diagnosis was recorded through surveillance or symptoms, and treatment was either palliative, percutaneous or surgical. Results We identified 197 cases of HBV-related HCC. The mean age was 57.9 ± 12.9 years; 83% were male, and 55.3% and 35.3% were of Asian and European descent respectively. Of 168 patient with available data, 146 (87%) had cirrhosis versus 22 (13%) without. Patients with cirrhosis tended to be older (median 60 vs 52 years, P = 0.078). Asian patients were more likely to have HCC without cirrhosis than Europeans (17% vs 6%, P = 0.04). There were no other differences identified between cirrhotic and non-cirrhotic patients. Thirty-four per cent of patients had tumours greater than 5 cm at diagnosis, and 47% were diagnosed after presenting with symptoms. Twelve patients with HBV-HCC were outside current screening guidelines. Conclusion Most patients in Melbourne with HBV-associated HCC have cirrhosis. HCC characteristics in non-cirrhotic and cirrhotic patients were similar. The large number of patients detected through symptoms and with large tumours reinforces the need for vigilance in screening. [ABSTRACT FROM AUTHOR]

Aim To evaluate trends in survival of patients with hepatocellular carcinoma ( HCC) at The Alfred over a 15-year period from 1995-2009 Methods A retrospective cohort study of patients with HCC comparing epidemiology, clinical presentation, treatment parameters and overall survival of those diagnosed between 1995-2001 and 2002-2009. Overall survival of patients with primary liver cancer. Results The study population consisted of 215 patients; 110 diagnosed between 1995-2001 (Cohort A) and 105 between 2002-2009 (Cohort B). Overall survival increased significantly between 1995-2010 ( P = 0.016); median survival was 365 days in Cohort A compared with 665 in Cohort B. The improvement in survival was associated with an increase in the proportion of cases detected at an asymptomatic stage ( P = 0.012), a decline in the severity of liver disease at diagnosis ( P = 0.002) and increased utilisation of loco-regional therapy ( P = 0.001) over the same period. Survival of patients detected through screening was significantly higher than those detected through non-screening methods (1309 vs 233 days, P < 0.001). Conclusions The survival of patients with HCC managed at a tertiary referral centre has improved over the period 1995-2009. This improvement may relate to the increased detection of the disease at an asymptomatic stage (e.g. through screening) as well as increased utilisation of effective loco-regional therapies for HCC. [ABSTRACT FROM AUTHOR]

The sensitivity of 31P MRS can be increased using higher magnetic fields, but also by using 1H to 31P polarization transfer techniques where the sensitivity is determined by the polarization of the proton spins and thus the signal-to-noise per unit time is unaffected by the slow T1 relaxation properties of the 31P spins. This implies that 31P spins can be manipulated during the T1 relaxation of the 1H spins without affecting the signal-to-noise of the 1H to 31P polarization transferred spins. It is shown here that by combining 1H to 31P polarization transfer with a direct 31P detection sequence in one repetition time, one can gain more signal-to-noise per unit of time as compared to a polarization transfer sequence alone. Proof of principle was demonstrated by phantom measurements and additionally the method was applied to the human calf muscle and to the human breast in vivo at 7T. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

During the last two decades, there has been growing interest in the integration of existing ideas and data to produce new synthetic models and hypotheses leading to discovery and advancement in estuarine and coastal science. This essay offers an integrated definition of what is meant by synthesis research and discusses its importance for exploiting the rapid expansion of information availability and for addressing increasingly complex environmental problems. Approaches and methods that have been used in published synthetic coastal research are explored and a list of essential steps is developed to provide a foundation for conducting synthetic research. Five categories of methods used widely in coastal synthesis studies are identified: (1) comparative cross-system analysis, (2) analysis of time series data, (3) balance of cross-boundary fluxes, (4) system-specific simulation modeling, and (5) general systems simulation modeling. In addition, diverse examples are used to illustrate how these methods have been applied in previous studies. We discuss the urgent need for developing curricula for classroom and experiential teaching of synthesis in coastal science to undergraduate and graduate students, and we consider the societal importance of synthetic research to support coastal resource management and policy development. Finally, we briefly discuss the crucial challenges for future growth and development of synthetic approaches to estuarine and coastal research. [ABSTRACT FROM AUTHOR]

Measurements of the production and consumption of organic material have been a focus of aquatic science for more than 80 years. Over the last century, a variety of approaches have been developed and employed for measuring rates of gross primary production (P), respiration (R), and net ecosystem production (P = P − R) within aquatic ecosystems. Here, we reconsider the range of approaches and applications for ecosystem metabolism measurements, and suggest ways by which such studies can continue to contribute to aquatic ecology. This paper reviews past and contemporary studies of aquatic ecosystem-level metabolism to identify their role in understanding and managing aquatic systems. We identify four broad research objectives that have motivated ecosystem metabolism studies: (1) quantifying magnitude and variability of metabolic rates for cross-system comparison, (2) estimating organic matter transfer between adjacent systems or subsystems, (3) measuring ecosystem-scale responses to perturbation, both natural and anthropogenic, and (4) quantifying and calibrating models of biogeochemical processes and trophic networks. The magnitudes of whole-system gross primary production, respiration and net ecosystem production rates vary among aquatic environments and are partly constrained by the chosen methodology. We argue that measurements of ecosystem metabolism should be a vital component of routine monitoring at larger scales in the aquatic environment using existing flexible, precise, and durable sensor technologies. Current and future aquatic ecosystem studies will benefit from application of new methods for metabolism measurements, which facilitate integration of process measurements and calibration of models for addressing fundamental questions involving ecosystem-scale processes. [ABSTRACT FROM AUTHOR]

A previously observed shift in the relationship between Chesapeake Bay hypoxia and nitrogen loading has pressing implications on the efficacy of nutrient management. Detailed temporal analyses of long-term hypoxia, nitrogen loads, and stratification were conducted to reveal different within-summer trends and understand more clearly the relative role of physical conditions. Evaluation of a 60-year record of hypoxic volumes demonstrated significant increases in early summer hypoxia, but a slight decrease in late summer hypoxia. The early summer hypoxia trend is related to an increase in Bay stratification strength during June from 1985 to 2009, while the late summer hypoxia trend matches the recently decreasing nitrogen loads. Additional results show how the duration of summertime hypoxia is significantly related to nitrogen loading, and how large-scale climatic forces may be responsible for the early summer increases. Thus, despite intra-summer differences in primary controls on hypoxia, continuing nutrient reduction remains critically important for achieving improvements in Bay water quality. [ABSTRACT FROM AUTHOR]

This study describes the influence of submersed plant beds on spatial distributions of key water quality variables. An on-board flow-through water sampling system was used to investigate patterns in turbidity, chlorophyll- a, temperature, dissolved oxygen, and pH across a robust stand of the submersed plant Stuckenia pectinata. Spatially interpolated maps show that water quality conditions were significantly altered within this plant bed, especially during months of peak biomass, and that reduction of suspended particles focused at the bed's edge. Comparison with a suite of submersed plant beds indicated that patterns were related to canopy height, shoot density, and cross-shore bed width. Wide and dense stands with tall canopies showed reduced turbidity and increased light penetration, while smaller sparser beds often showed elevated within-bed turbidity. These results suggest that bed effects on water quality conditions vary seasonally with plant canopy architecture and bed size, providing tentative guidelines for restoring self-sustaining beds. [ABSTRACT FROM AUTHOR]